Quest 1 & 2

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Question 1

Decision making is a function relegated to department officers of rank who are empowered with the authority to make decisions that affect many other emergency response personnel. Discuss the concepts and importance of CRM and The 2&7 Tool as both are applied to the fire service. Include details of each element of both managerial decision making applications.

Your response should be at least 200 words in length. You are required to use at least your textbook as source material for your response. All sources used, including the textbook, must be referenced; paraphrased and quoted material must have accompanying citations.

19 points

Question 2

Hazardous material incidents require keen observation and a cautious approach, as many hazardous materials may not be properly identified or known to emergency responders. Incident management is critical in order to reduce injury and loss of life. Discuss the appropriate methodology for approaching a hazardous material incident. Include details of managerial responsibility and personnel safety, including proper protective clothing.

Your response should be at least 200 words in length. You are required to use at least your textbook as source material for your response. All sources used, including the textbook, must be referenced; paraphrased and quoted material must have accompanying citations.

19 points

 
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Make A SOAP Note: Assessing Ear, Nose, And Throat

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Make a SOAP Note: Assessing Ear, Nose, and Throat

Most ear, nose, and throat conditions that arise in non-critical care settings are minor in nature. However, subtle symptoms can sometimes escalate into life-threatening conditions that require prompt assessment and treatment. Nurses conducting assessments of the ears, nose, and throat must be able to identify the small differences between life-threatening conditions and benign ones. For instance, if a patient with a sore throat and a runny nose also has inflamed lymph nodes, the inflammation is probably due to the pathogen causing the sore throat rather than a case of throat cancer. With this knowledge and a sufficient patient health history, a nurse would not need to escalate the assessment to a biopsy or an MRI of the lymph nodes, but would probably perform a simple strep test.

In this Discussion, you consider case studies of abnormal findings from patients in a clinical setting. You determine what history should be collected from the patients, what physical exams and diagnostic tests should be conducted, and formulate a differential diagnosis with several possible conditions.

Note: By Day 1 of this week, your instructor will have assigned you to one of the following case studies to review for this Discussion. Also, your Discussion post should be in the SOAP Note format, rather than the traditional narrative style Discussion posting format. Refer to Chapter 2 of the Sullivan text and the Comprehensive SOAP Template in the Week 4 Learning Resources for guidance. Remember that not all comprehensive SOAP data are included in every patient case.

Case 1: Nose Focused Exam

Richard is a 50-year-old male with nasal congestion, sneezing, rhinorrhea, and postnasal drainage. Richard has struggled with an itchy nose, eyes, palate, and ears for 5 days. As you check his ears and throat for redness and inflammation, you notice him touch his fingers to the bridge of his nose to press and rub there. He says he’s taken Mucinex OTC the past two nights to help him breathe while he sleeps. When you ask if the Mucinex has helped at all, he sneers slightly and gestures that the improvement is only minimal. Richard is alert and oriented. He has pale, boggy nasal mucosa with clear thin secretions and enlarged nasal turbinates, which obstruct airway flow but his lungs are clear. His tonsils are not enlarged but his throat is mildly erythematous.

Case 2: Focused Throat Exam

Lily is a 20-year-old student at the local community college. When some of her friends and classmates told her about an outbreak of flu-like symptoms sweeping her campus over the past two weeks, Lily figured she shouldn’t take her three-day sore throat lightly. Your clinic has treated a few cases similar to Lily’s. All the patients reported decreased appetite, headaches, and pain with swallowing. As Lily recounts these symptoms to you, you notice that she has a runny nose and a slight hoarseness in her voice but doesn’t sound congested.

Case 3: Focused Ear Exam

Martha brings her 11-year old grandson, James, to your clinic to have his right ear checked. He has complained to her about a mild earache for the past two days. His grandmother believes that he feels warm but did not verify this with a thermometer. James states that the pain was worse while he was falling asleep and that it was harder for him to hear. When you begin basic assessments, you notice that James has a prominent tan. When you ask him how he’s been spending his summer, James responds that he’s been spending a lot of time in the pool.

To prepare:

With regard to the case study you were assigned:

·         Review this week’s Learning Resources and consider the insights they provide.

·         Consider what history would be necessary to collect from the patient.

·         Consider what physical exams and diagnostic tests would be appropriate to gather more information about the patient’s condition. How would the results be used to make a diagnosis?

·         Identify at least 10 possible conditions that may be considered in a differential diagnosis for the patient.

Note: Before you submit your initial post, replace the subject line (“Week 5 Discussion”) with “Review of Case Study ___,” identifying the number of the case study you were assigned.

Address the following in the SOAP Note:

1.     A description of the health history you would need to collect from the patient in the case study to which you were assigned.

2.     Explain what physical exams and diagnostic tests would be appropriate and how the results would be used to make a diagnosis.

3.      List five different possible conditions for the patient’s differential diagnosis and justify why you selected each.

REFERENCES:

Readings

·         Ball, J. W., Dains, J. E., Flynn, J. A., Solomon, B. S., & Stewart, R. W. (2015). Seidel’s guide to physical examination (8th ed.). St. Louis, MO: Elsevier Mosby.

o    Chapter 10, “Head and Neck” (pp. 184-203)

This chapter reviews the anatomy and physiology of the head and neck. The authors also describe the procedures for conducting a physical examination of the head and neck.

o    Chapter 11, “Eyes” (pp. 204-230)

In this chapter, the authors describe the anatomy and function of the eyes. In addition, the authors explain the steps involved in conducting a physical examination of the eyes.

o    Chapter 12, “Ears, Nose, and Throat” (pp. 231-259)

The authors of this chapter detail the proper procedures for conducting a physical exam of the ears, nose, and throat. The chapter also provides pictures and descriptions of common abnormalities in the ears, nose, and throat.

·         Dains, J. E., Baumann, L. C., & Scheibel, P. (2016). Advanced health assessment and clinical diagnosis in primary care (5th ed.). St. Louis, MO: Elsevier Mosby.

o    Chapter 15, “Earache” (pp. 174–183)

This chapter covers the main questions that need to be asked about the patient’s condition prior to the physical examination, as well as how these questions lead to a focused physical examination.

o    Chapter 21, “Hoarseness” (pp. 248-255)

This chapter focuses on the most common causes of hoarseness. It provides strategies for evaluating the patient both through questions and through physical exams.

o    Chapter 25, “Nasal Symptoms and Sinus Congestion” (pp.301-309)

In this chapter, the authors highlight the key questions to ask about the patients symptoms, the key parts of the physical examination, and potential laboratory work that might be needed to provide an accurate diagnosis of nasal and sinus conditions.

o    Chapter 30, “Red Eye” (pp. 357-368)

The focus of this chapter is on how to determine the cause of red eyes in a patient, including key symptoms to consider and possible diagnoses.

o    Chapter 32, “Sore Throat” (pp. 381-389)

A sore throat is one most common concerns patients describe. This chapter includes questions to ask when taking the patient’s history, things to look for while conducting the physical exam, and possible causes for the sore throat.

o    Chapter 38, “Vision Loss” (pp. 446-457)

This chapter highlights the causes of vision loss and how the causes of the condition can be diagnosed.

·         Sullivan, D. D. (2012). Guide to clinical documentation (2nd ed.). Philadelphia, PA: F. A. Davis.

o    Chapter 5, “SOAP Notes” (pp. 91–118)

Note: Download the seven documents (Adult Examination Checklists and Physical Exam Summaries) below, and use them as you practice conducting assessments of the head, neck, eyes, ears, nose, and throat.

·         Seidel, H. M., Ball, J. W., Dains, J. E., Flynn, J. A., Solomon, B. S., & Stewart, R. W. (2011). Adult examination checklist: Guide for head, face, and neck. In Mosby’s guide to physical examination (7th ed.). St. Louis, MO: Elsevier Mosby.

This Adult Examination Checklist: Guide for Head, Face, and Neck was published as a companion to Seidel’s guide to physical examination (8th ed.), by Ball, J. W., Dains, J. E., & Flynn, J. A. Copyright Elsevier (2015). Fromhttps://evolve.elsevier.com/

·         Seidel, H. M., Ball, J. W., Dains, J. E., Flynn, J. A., Solomon, B. S., & Stewart, R. W. (2011). Adult examination checklist: Guide for eye assessment. In Mosby’s guide to physical examination (7th ed.). St. Louis, MO: Elsevier Mosby.

This Adult Examination Checklist: Guide for Eye Assessment was published as a companion to Seidel’s guide to physical examination (8th ed.), by Ball, J. W., Dains, J. E., & Flynn, J. A. Copyright Elsevier (2015). Fromhttps://evolve.elsevier.com/

·         Seidel, H. M., Ball, J. W., Dains, J. E., Flynn, J. A., Solomon, B. S., & Stewart, R. W. (2011). Adult examination checklist: Guide for ear assessment. In Mosby’s guide to physical examination (7th ed.). St. Louis, MO: Elsevier Mosby.

This Adult Examination Checklist: Guide for Ear Assessment was published as a companion to Seidel’s guide to physical examination (8th ed.), by Ball, J. W., Dains, J. E., & Flynn, J. A. Copyright Elsevier (2015). Fromhttps://evolve.elsevier.com/

·         Seidel, H. M., Ball, J. W., Dains, J. E., Flynn, J. A., Solomon, B. S., & Stewart, R. W. (2011). Adult examination checklist: Guide for nose, paranasal sinuses, mouth, oropharynx. In Mosby’s guide to physical examination (7th ed.). St. Louis, MO: Elsevier Mosby.

This Adult Examination Checklist: Guide for Nose, Paranasal Sinuses, Mouth, Oropharynx was published as a companion toSeidel’s guide to physical examination (8th ed.), by Ball, J. W., Dains, J. E., & Flynn, J. A. Copyright Elsevier (2015). From https://evolve.elsevier.com/

·         Seidel, H. M., Ball, J. W., Dains, J. E., Flynn, J. A., Solomon, B. S., & Stewart, R. W. (2011). Physical exam summary: Ears, nose, and throat. In Mosby’s guide to physical examination (7th ed.). St. Louis, MO: Elsevier Mosby.

This Ears, Nose, and Throat Physical Exam Summary was published as a companion to Seidel’s guide to physical examination(8th ed.), by Ball, J. W., Dains, J. E., & Flynn, J. A. Copyright Elsevier (2015). Fromhttps://evolve.elsevier.com

·         Seidel, H. M., Ball, J. W., Dains, J. E., Flynn, J. A., Solomon, B. S., & Stewart, R. W. (2011). Physical exam summary: Eyes. In Mosby’s guide to physical examination (7th ed.). St. Louis, MO: Elsevier Mosby.

This Eyes Physical Exam Summary was published as a companion to Seidel’s guide to physical examination (8th ed.), by Ball, J. W., Dains, J. E., & Flynn, J. A. Copyright Elsevier (2015). From https://evolve.elsevier.com/

·         Seidel, H. M., Ball, J. W., Dains, J. E., Flynn, J. A., Solomon, B. S., & Stewart, R. W. (2011). Physical exam summary: Head, face, and neck. In Mosby’s guide to physical examination (7th ed.). St. Louis, MO: Elsevier Mosby.

This Head and Neck Physical Exam Summary was published as a companion to Seidel’s guide to physical examination (8th ed.), by Ball, J. W., Dains, J. E., & Flynn, J. A. Copyright Elsevier (2015). Fromhttps://evolve.elsevier.com/

·         Browning, S. (2009). Ear, nose, and throat problems. General Practice Update, 2(9), 9–13.

Retrieved from the Walden Library databases.

This article contains a question and answer session on ear, nose, and throat problems. The article reviews specific topics, such as when to use eardrops and new post-nasal drip treatments, and the referral of persisting cough cases by general practitioners.

·         Lloyd, A., & Pinto, G. L. (2009). Common eye problems. Clinician Reviews, 19(11), 24–29.

Retrieved from the Walden Library databases.

The authors of this article describe different eye problems, their symptoms, and recommended treatments. The authors also emphasize the need to conduct an eye exam and take an ocular history.

·         Otolaryngology Houston. (2014). Imaging of maxillary sinusitis (X-ray, CT, and MRI). Retrieved fromhttp://www.ghorayeb.com/ImagingMaxillarySinusitis.html

This website provides medical images of sinusitis, including X-rays, CT scans, and MRIs (magnetic resonance imaging).

Media

Online media for Seidel’s Guide to Physical Examination

It is highly recommended that you access and view the resources included with the course text, Seidel’s Guide to Physical Examination. Focus on the videos and animations in Chapters 10, 11, and 12 that relate to the assessment of the head, neck, eyes, ears, nose, and throat. Refer to Week 4 Learning Resources area for access instructions on https://evolve.elsevier.com/.

Optional Resources

·         LeBlond, R. F., Brown, D. D., & DeGowin, R. L. (2009). DeGowin’s diagnostic examination (9th ed.). New York, NY: McGraw Hill Medical.

o    Chapter 7, “The Head and Neck” (pp. 178–301)

This chapter describes head and neck examinations that can be made with general clinical resources. Also, the authors detail syndromes of common head and neck conditions.

 
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Informative Speech Outline-Instructions And Sample Attached

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Topic Selection

This assignment requires you to research a job field that you already work in or that you may wish to enter someday to show how someone can use it as a platform for promoting something God values in the world. See the Alban text pp. 405–480 for descriptions of several job fields you may wish to consider for the purpose of this project.  list of things God values in the world.

Speech Goals: Because this is an informative speech—a speech in which you merely report information from credible sources without expressing your personal opinion—your goal in this presentation is simply to use information from appropriately credited expert sources in 2 ways:

(1)  To describe this occupation to your audience; and,

(2)  To show through documented examples or expert quotations how people can use this occupation as a platform for advancing something that God values according to the list of things God values that appears in the Alban text, pp. 73–76.

Among the many occupation-related points you could communicate to your audience in this informative speech are the nature of the work, the training or credentials required, employment-related trends, future outlook there, pay scale, etc. See the “Profiles” section on the WebCOM site for examples of people from a variety of occupational fields who have used job skills/situations as platforms for promoting something God values in the world.

Other Topic Criteria: Your topic must satisfy not only the preceding criteria, but also the topic selection criteria set forth in the Alban text and the Liberty University Online Honor Code. In addition, your topic must comply with the following:

· Topic Appropriateness: Avoid any topic that leads you to portray legally or ethically questionable texts or behaviors in a favorable light. This includes but is not limited to theses that advance sexually promiscuous activity, the use of illegal substances, or other behaviors that Liberty University’s statement of values prohibits. Questions about the appropriateness of topics, sources, etc. should be directed to your instructor early in the speech-planning process.

· Topic Originality: Your speech topics MUST be researched, selected, and delivered primarily for this course and not primarily for, or in conjunction with, a presentation for a church group, a Sunday School class, a social group, or any other small group. You may not give a speech that serves a double purpose.

· Topic Grading Criteria: You must choose a topic that enables you to construct the speech in a way that satisfies the specific requirements of the Speeches Grading Rubric, which lists the criteria that your instructor will use when grading your presentation.

Research, Organization, and Outlining

Basic Requirements: For your informative speech, you are required to:

(1) Research credible sources for information about your topic.

(2) Form a main idea for your speech based on your research.

(3) Express this main idea as a complete thought in a single declarative thesis statement sentence.

(4) Choose the information from your research that most powerfully delivers the type of information that this thesis statement requires.

(5) Present this information in a logically sequenced outline of properly documented main points, sub-points, and perhaps even sub-sub-points, using the Informative Speech Outline Template document as your formatting guide. Your outline in its final form will serve as the blueprint that you mentally must follow while extemporaneously delivering the speech to your audience.

· Research Requirements: For your informative speech, you are required to use 3 expert sources. You must use and clearly cite examples, illustrations, statistics, quotations from experts, etc. from at least 3 expert sources in this project. An expert source is a person, group of persons, or organization with documentable expertise in the area it addresses. Information from such sources typically derives from personal interviews with credentialed experts or from documentable print and/or electronic publications

· The Bible as an Expert Source: While you may of course use the Bible as a source when related to your topic, it must be in addition to the 3 required sources.

· Non-Expert Sources: Never use information from anonymous or questionable sources such as Wikipedia or any printed source authored by someone whose credentials for addressing the topic are not clearly established.

· Liberty University Database Source Options: It behooves you to consult the Liberty University Library’s research portal for access to many potentially useful, credible databases.

Organization and Outlining Requirements

Topical Sequencing Required: You must use the Topical organizational pattern for addressing your topic (see the Alban text page 221–222 for more about this).

The Draft and the Final Outlines: The speech outline process involves 2 submissions. If you post the optional draft version of your outline by the Module/Week 3 deadline for it, your instructor will post constructive feedback that you should heed and assimilate as you compose the final outline for submission a week later. The draft outline (if you do it) and the final outline must be submitted as Microsoft Word documents via the designated Blackboard submission links.

Use the Outline Template: You must use the Informative Speech Outline Template document as a guide for constructing your speech outline. Retain the given formatting. Provide information for each category—an audience description, organizational pattern, purpose statement, etc. Include clearly distinguished introduction, body, and conclusion sections.

Outline Parts:

· The introduction must be listed in this order: your attention-getter, motive-for-listening, credibility statement, purpose statement, and preview statement.

· The body must include 2–5 main points, each with supportive subpoints, and perhaps even sub-subpoints. These will consist mainly of documented examples, illustrations, statistics, quotations from experts, etc. that you have derived from the 3 or more expert sources that this project requires.

· The conclusion must include a summary statement and a concluding element that refocuses the audience’s attention on the main point.

· The Works Cited (MLA), Reference page (APA), or Bibliography (Turabian) must properly credit your sources and must do so in the format prescribed by the respective format used.

Document Your Sources Properly:

 
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Please I Need This By Tomorrow At 1pm….

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Physical Science multiple choice test….

I have attached the pictures to certain questions at the bottom…. labeled question 3….

1.  Use the equation:

frequency=wavespeed/wavelength

and the wavelength you found in #3 to calculate the frequency of this photon (remember the speed of light is 3E8 m/s):

  • 7.6E14 Hz
  • 6.0E14 Hz
  • 4.6E14 Hz

2. Use the energy equation from this week’s notes, your answer from #5, and Plank’s constant (6.63E-34) to find the approximate energy of this photon:

  • 4.8E-19 Joules
  • 3.0E-19 Joules
  • 3.0E-17 Joules
  • 1.21 Gigawatt

3. A glass tube is filled with hydrogen gas.  An electric current is passed through the tube, and the tube begins to glow a pinkish/purple color (this is how fluorescent bulbs and neon signs produce light). If you were to pass this pink light through a prism to separate the individual light frequencies, you would see that this pink light is composed of four distinct colors: violet, green, blue, and red.  Notice the similarity between image (b) above and image (b) from question #3.

Which is the best description of why this occurs?

  • A. 
  • B. 
  • C. 

4. The lights used by Mark Watley (played by Matt Damon) during the film The Martian seem to be Metal Halide lamps.  Metal Halide lamps are filled with vaporized mercury and metal-halogen compounds.  When an electric current is passed through the lamp, the tube begins to glow a bright white/blue color. If you were to pass this light through a prism to separate the individual light frequencies, you would see a rainbow just as you would if using natural sunlight because of the complexity of the metal halide gas and the vast amount of possible electron transitions.

(The study of light in this way is known as spectroscopy and allows astronomers to know exactly what atoms compose distant stars, simply by looking at the light they emit.  The spectral lines an atom produces uniquely identifies that atom just like a fingerprint uniquely identifies a person.

The momentum equation and energy equation that we have used above can be combined to give the following equation: (c=E/p)

where again p is the phonon momentum, E is the photon energy and c is the speed of light.  When you divide the photon energy found in #6 by the photon momentum found in #4, do you get the speed of light?

(If not, check your work for questions #4 through #6).

  • Yes
  • No

5. All visible light (light that our eyes can detect) has wavelength between 400-700 nanometers. Wavelengths just smaller than 400 nm are Ultraviolet light. Wavelengths just larger than 700 nanometers are infrared light. What type of light is the Balmer series light that we have consider so far?

  • Visible
  • Ultraviolet
  • Infrared

6. The solar panels used by Mark function because of the photoelectric effect. Light shines on the cells causing electrons to be ejected from the metal, which produces an electric current. At night on Mars, no light will fall on the solar cells and no electric current will be generated. According to your notes, what type of light is typically needed to cause the photoelectric effect?

  • Visible
  • Ultraviolet
  • Infrared

7. If we were to illuminate them only with light from the Balmer transition considered above, would the solar panels produce a current?

  • Yes
  • No

8. Starting with only the Balmer series light (visible light), how could we ensure that the solar panels generate a current that Mark can use for his power station? (It may help to look at the electromagnetic spectrum from week 3):

  • By gradually increasing the brightness (amount) of light that we shine on it.
  • By gradually increasing the frequency of the light we shine on it.
  • By gradually increasing the wavelength of the light that we shine on it.

9. Imagine you are riding on a yacht in the ocean and traveling at 20 mph.  You then hit a golf ball at 100 mph from the deck of the yacht.  You see the ball move away from you at 100mph, while a person standing on a near by beach would observe your golf ball traveling at 120 mph (20 mph + 100 mph).

Now imagine you are aboard the Hermes spacecraft traveling at 0.1c (1/10 the speed of light) past Mars and shine a laser from the front of the ship. You would see the light traveling at c (the speed of light) away from your ship.  According to Einstein’s special relativity, how fast will a person on Mars observe the light to be traveling?

  • 0.1c (1/10 the speed of light)
  • c (the speed of light)
  • 1.1c (c+0.1c)

10. Note: The following questions are unrelated to the Balmer series or The Martian.  Please refer to your course notes.

A Sun-sized star will spend most of its lifetime as a:

  • White Dwarf
  • Red Giant
  • Protostar
  • Main-Sequence Star

11. Our Sun will eventually:

  • explode in a supernova.
  • become a white dwarf star.
  • become a black hole.

12. A main sequence star does not expand or contract due to the balance between the internal heat pushing outward and the weight of the material pressing inward due to gravity.  This state of maintaining a constant size is known as:

  • hydrostatic equilibrium
  • thermal equilibrium
  • dynamic equilibrium

13. Neutron stars are:

  • Low density star remnants with many neutrons, which mass is less than the mass of the Sun.
  • Incredibly small remnants of super massive stars where the gravitational collapse is stop by neutron degeneracy.
  • Incredibly big and massive star remnants which expelled all its neutrons in a supernova explosion.

14. Black holes are:

  • Star remnants from super massive stars which gravitational collapse can not be halt by electron or neutron degeneracy and gravity is so strong in their vicinity that not even light can escape.
  • Regions of the universe with space empty of matter or radiation that becomes so dark that forbids us from investigating it.
  • Regions of space where matters is not sufficiently hot to radiate in the visible spectrum.

15. Which of the following states that all matter tends to “warp” space in its vicinity and that objects react to this warping by changing their paths?

  • Newton’s Universal Law of Gravitation
  • Einstein’s General Relativity
  • Einstein’s Special Relativity
  • Newton’s First Law of Motion

16.  Wave-particle duality tells us that wave and particle models apply to all objects whatever the size, so why don’t we observe wave properties in macroscopic objects?

  • Because their particle properties forbid us from observing their wave properties.
  • Because their wavelength is extremely long (undetectable).
  • Because their wavelength is extremely short (undetectable).
 
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Consequences Of The Fall And Contemporary Response

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Consequences of the Fall and Contemporary Response

In this assignment, you will identify the consequences of the fall of humanity that leads to human suffering, and describe how a Christian organization fights back for creational purpose.

One of the central components of every worldview is the topic of human nature. The topic of human nature asks questions about human value, human flourishing, and human purpose. Within the Christian worldview, the issue of sin and the consequences of the fall factor prominently into the topic of human nature.

In the “Consequences of the Fall and Contemporary Response” three-part document, you will explore the topic of human nature from the perspective of the Christian worldview. The first part of the assignment involves examining the immediate implications of the fall. The second and third parts of the assignment address how the effects of the fall are still evident in the world today.

For Part Two and Part Three, you will select an organization from the “Christian Organizations That Address a Consequence of the Fall” list provided in the topic study materials.

While GCU style is not required for the body of this assignment, solid academic writing is expected, and documentation of sources should be presented using APA documentation guidelines, which can be found in the GCU Style Guide, located in the Student Success Center.

This assignment uses a rubric. Please review the rubric prior to beginning the assignment to become familiar with the expectations for successful completion.

You are required to submit this assignment to LopesWrite. Refer to the LopesWrite Technical Support articles for assistance.

Reminder: This is a templated document so the LopesWrite score will be higher due to the directions and questions.

 
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CSTU 101 QUIZ 5

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Question 1 

  1. Which country dispersed the Ten      Tribes of Israel in 722BC?

Rome

Babylonians

Egyptians

Assyrians

3 points

Question 2 

  1. If the early Christians had      worshiped Jesus and Caesar, they would have gone unharmed, but they      rejected all forms of __________________.

Pantheism

Atheism

Syncretism

Agnosticism

3 points

Question 3 

  1. Old Testament prophet of faith,      who preached on abiding trust in the providence of God around 740–700 BC.

Amos

Isaiah

Daniel

Malachi

3 points

Question 4 

  1. Who was the Latin-speaking      Christian who mastered Greek and Hebrew, and produced a translation of the      whole Bible known as the Vulgate?

Ambrose

Jerome

Augustine

Aristotle

3 points

Question 5 

  1. Who wrote The Wealth of Nations?

Luther

Calvin

Smith

Zwingli

3 points

Question 6 

  1. One event not depicted in the      catacombs was:

The good Shepard

Jonah

Moses parting the   Red Sea

The crucifixion

3 points

Question 7 

  1. This Scripture used by modern      Christianity is remarkably consistent. It was written over a period of      1,500 years, by at least ______ different writers and yet remains true to      one theme and has a unified viewpoint on both philosophy and facts.

50

40

60

20

3 points

Question 8 

  1. During the time of Nero, there was      the first recorded persecution of Christians that took place after a      terrible destruction in the city of Rome in what year?

50 AD

70 AD

64 AD

30 AD

3 points

Question 9 

  1. In the Sarcophagus of Junius      Bassus, which two figures are standing on either side of Jesus?

Peter and Paul

Moses and Elijah

James and John

Peter and John

3 points

Question 10 

  1. His interpretation of history      quickly replaced those of classical thinkers and has remained influential      to the present day.  Lived (354-430).

Arian

Donatus

Augustine

Phillip

3 points

Question 11 

  1. What would be a chief mark      describing the Roman Empire, even after Constantine.

Excitement

Apathy

Focused

Motivated

3 points

Question 12 

  1. Who was the Bishop in (339-397)      who successfully challenged and limited imperial authority over the      church?

Constantine

Augustine

Ambrose

Jerome

3 points

Question 13 

  1. The rise of Rome caused a shift      from the Greek view of the individual as the ultimate reality to one in      which reality was the

State

City

3 points

Question 14 

  1. Meeting in small groups in private      homes, early Christians conducted simple services centered on      the____________: the consecrated bread and wine commemorating Christ’s      sacrifice on the cross.

Oran

Eucharist

Penance

Chrismation

3 points

Question 15 

  1. Constantine played an influential      role in the proclamation of the _____________, which decreed tolerance for      Christianity in the empire.

Edict of Rome

Edict of   Constantine

Edict of Milan

Proclamation of   Peace

3 points

Question 16 

  1. According to your textbook, what      was the basic strength of the Jews? It gave them a will to resist and to      survive.

High Priest

The people

Their religion

The location of   their land

3 points

Question 17 

  1. Early Christian art was more      _________ and less materialistic, than Roman art because it was hard to      depict topics like the Trinity or Salvation.

Pragmatic

Symbolic

Realistic

Imperialistic

3 points

Question 18 

  1. The Torah consists of the      first five books of the Bible called the Pentateuch,      which is also known as

Books of David

Books of Abraham

Books of Moses

Both a and b

3 points

Question 19 

  1. What word could be used in      association with Christian Coptic Art?

Exact

Nimbus

Modern

Classical

3 points

Question 20 

  1. Approximately what year did      Constantine declare Christianity a legal religion of Rome?

285 AD

452 AD

313 AD

230 AD

3 points

Question 21 

  1. The prohibition of graven images      separated Judaism from all other religions, which represented their gods      in a variety of ways.

True

False

2 points

Question 22 

  1. In the early Christian church,      when a person became a Christian and accepted baptism, he was welcomed      into the Roman Culture because of his strong moral character.

True

False

2 points

Question 23 

  1. For centuries the Romans had      constructed basilicas that served as meeting halls, mercantile centers,      and halls of justice. The basilica was a prototype of the large, dignified      structure Christians needed for worship services.

True

False

2 points

Question 24 

  1. Life in the later years of the      Roman Empire was marked by increasing optimism about the future.

True

False

2 points

Question 25 

  1. As we learned in the presentation      “Introduction to Rome and Christianity,” the National Gallery of      Art Museum resembles the Parthenon in Greece.

True

False

2 points

Question 26 

  1. By the 5th century the      Bishop of Rome was calling himself the Pope (Lat., papa, “father”)      Christ’s vicar on earth.

True

False

2 points

Question 27 

  1. Christianity was not equalitarian      and certain restrictions were put on slaves and Greeks.

True

False

2 points

Question 28 

  1. The New Testament is silent on the      philosophies of the Roman world.

True

False

2 points

Question 29 

  1. Pompeii was one of the only      provinces of Rome that did not get caught up in all of the sexual      representation.

True

False

2 points

Question 30 

  1. Paul’s prologue on the Logos has      been very beneficial to the growth of Christianity?

True

False

 
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Anthropology Life And Producing Variation

/in /by

Genetics: Reproducing Life and Producing Variation

CLARK SPENCER LARSEN

E S S E N T I A L S O F PHYSICAL ANTHROPOLOGY SECOND EDITION

CHAPTER

3

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Copyright ©2013 W.W. Norton, Inc.

Genetics: Reproducing Life and Producing Variation

  • Questions addressed in this chapter:
  • What is the genetic code?
  • What does the genetic code (DNA) do?
  • How does understanding genes help us understand variation?

The last chapter ended with a brief introduction to DNA. But, what is DNA? What is it made of? And how can a small molecule like DNA ‘code’ for all of the traits in a living organism? We will address these and other questions in this chapter. Ultimately, what we are doing in this chapter is understanding how the genetic code (DNA) results in variation, because it is this variation that natural selection can act upon and lead to evolutionary changes. We will start by looking at the fundamental unit of all life on Earth: the cell. Inside each cell, the DNA code is structured into packages known as chromosomes. We will see how the DNA molecule can copy itself so that each cell in an organism’s body contains the same DNA information. We will then look at how DNA codes for proteins, which all living organisms are made of. Finally, we will look at a concrete example of how DNA impacts our lives by examining human blood types. Though we have to dive into the microscopic world, do not lose sight of the big picture: DNA is a code for making proteins, and we are made of proteins. If the DNA slightly changes (through mutation, which we met in the last chapter), the protein changes, and thus the organism can change.

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Copyright ©2013 W.W. Norton, Inc.

The Cell: Prokaryotes

  • Prokaryotes
  • 3.5 billion years old
  • Single-celled bacteria
  • No nucleus or organelles

All living organisms are made of cells; they are the basic units of life. There are many, many organisms that are made of just one cell, and many (including you) that are made of trillions of cells. All of life can be divided into two big categories, depending on the kind of cell they have. The first kind are organisms called prokaryotes. Prokaryotes are single-celled bacteria without nuclei or any special structures called organelles. They often have structures shown here in this image, like a cell wall, an outer membrane, a cytoplasm within which the DNA resides, and they often have locomotor structures like a flagellum. On this slide is a microscopic image of a prokaryotic cell that we have all heard of: Escherichia coli (E. coli), which lives in the guts of many mammals, including humans. Though prokaryotic cells live within us, and have been instrumental factors in driving human evolution, we will turn now to the cells we are made of: eukaryotic cells.

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Copyright ©2013 W.W. Norton, Inc.

The Cell: Eukaryotes

    • Eukaryotes
    • 1.2 billion years ago.
    • Some single-celled; all multicellular organisms (including humans)
    • DNA contained in a nucleus
    • Organelles

 

All animals, plants, fungi, and many single-celled organisms called protists are made of eukaryotic cells. These cells have a nucleus that contains DNA, and often have membrane-bound parts of the cell called organelles. These include chloroplasts (found in plants) and mitochondria, which help produce the molecular energy that powers cellular processes. Notice in this image that the eukaryotic cell is a bit more complicated than a prokaryotic cell. The microscopic image here is of kidney cells, which clearly have a nucleus, a membrane keeping the components of the cell contained, and a fluid within the cell called a cytoplasm.

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Copyright ©2013 W.W. Norton, Inc.

The Cell: Somatic Cells and Gametes

  • Somatic cells
  • Body cells
  • Full DNA (humans: 46 chromosomes)
  • Mitosis
  • Gametes
  • Eggs (ova) and sperm
  • Half DNA (humans; 23 chromosomes)
  • Meiosis

There are two types of eukaryotic cells in all animals and plants: somatic cells and gametes. Somatic cells, also called body cells, are found all over the body. Shown in the above image are the somatic cells found in the (clockwise from top left) brain, blood, bone, and skin. Somatic cells all contain a complete copy of the organism’s DNA. For example, in humans, somatic cells have all of the DNA packed in 46 chromosomes. Somatic cells also replicate through a process called mitosis, which we will learn about in just a moment. At the bottom right is an image of the other kind of eukaryotic cells: gametes. The large round cell is called an egg, or an ova. The small wiggly structures surrounding the egg are sperm. These are gametes. They contain only half of the organism’s DNA (23 chromosomes in humans) and replicate through a process known as meiosis.

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Copyright ©2013 W.W. Norton, Inc.

Chromosomes

  • DNA packaged in chromosomes
  • Chromosome number varies by species
  • Number of chromosomes does not correlate with complexity

Since we just mentioned chromosomes, it is worth examining chromosome number in a bit more detail. Humans have 46 chromosomes in our somatic cells. 23 of these came from our mother, and 23 from our father, for a grand total of 46. But, this number, 46, is not special at all. Other apes, like chimpanzees, have 48 chromosomes. Some primates have fewer chromosomes, like the colobus monkey which has 44. Some organisms we would consider to be less complex than us have fewer chromosomes, like the house fly with 12 or the salamander with 24. But, plenty of organisms have more than we have, like the potato with 48, the camel with 70, or algae, which has 148 chromosomes. Classifying organisms by the number of chromosomes they have would be like organizing books in a library based on the number of pages they have, or by the color of its jacket cover. It wouldn’t make sense. What matters are not the number of chromosomes an organism has, but the similarity in DNA that is packaged in the chromosomes. For instance, humans and chimpanzees share about 98% of their DNA. This is remarkable, and, in some ways, indicates how important 2% of a difference can be.

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Copyright ©2013 W.W. Norton, Inc.

DNA: The Blueprint of Life

• DNA

Genes

Chromosomes

Genome

• Nuclear DNA:

homoplasmic

• Mitochondrial DNA:

heteroplasmic

Most likely, you have all heard of DNA, and have probably heard that it is the “blueprint,” or “recipe,” or “code” for life? But, how does this work? It helps first to understand the structure of DNA, and to understand how it is packaged in your cells. It is estimated that there is six feet worth of DNA in every cell in your body. Six feet!? If cells are microscopic, how can this be? As shown in this image, the DNA molecule is wound up into compact structures that we have already encountered: chromosomes. Sections of that DNA specifically code for a specific protein in the body: These are called genes. The genome is all of the genes put together in all of the chromosomes. The DNA that is in the nucleus of our cells is called homoplasmic, meaning it is more or less the exact same in every cell in our body. But, the nucleus is not the only place in a cell that contains DNA. An organelle called the mitochondria also contains DNA. Mitochondrial DNA (mtDNA) is much, much smaller; it only contains 37 genes. And these genes are only inherited from your mother, meaning they can be used to trace one’s maternal lineage (called a matriline). Unlike nuclear DNA, mitochondrial DNA can differ from cell to cell, making it heteroplasmic.

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Copyright ©2013 W.W. Norton, Inc.

DNA: The Blueprint of Life

  • DNA structure
  • Sugar
  • Phosphate
  • Nucleotide base
  • Adenine (A)
  • Thymine (T)
  • Guanine (G)
  • Cytosine (C)
  • A with T
  • C with G
  • CAAAT
  • GTTTA

We are finally ready to discuss what DNA actually is. It is a molecule; in fact, a very simple one. DNA is made of three things: a type of sugar, a phosphate group, and a nucleotide base pair. The sugar and phosphate form the backbone of the long DNA molecule and these do not vary along the chain. What varies along the chain are the nucleotide base pairs. These bases can be one of four types: adenine (A), thymine (T), guanine (G) and cytosine (C). You can think of DNA as a ladder with the sugar and phosphates forming the uprights, and the bases forming the rungs. The rungs are made of two base pairs that cling together using hydrogen bonds. Critical to understanding DNA is the fact that the base pairs do not randomly cling to each other. Instead, A only clings to T, and C only clings to G. These are called complementary bases. What this means is, if you know one side of the DNA chain, you know the other. If a DNA sequence is CAAAT, the other side MUST be GTTTA. Though any two humans may have over 99% of their DNA base pair order identical, there are, of course, differences. Differences in these single nucleotide regions are called SNPs (pronounced “snips” and short for single nucleotide polymorphisms). These are some of the areas of the genome that can be used to solve crimes using DNA evidence since they can vary from one individual to another.

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Copyright ©2013 W.W. Norton, Inc.

The DNA Molecule: Replicating the Code

The very structure of DNA explains how it is so easily, and so accurately, replicated. When a cell is going to divide, it copies its entire genome. Remember those nucleotide base pairs? Well, there are 3 billion of them to copy each time a cell divides. And cells divide all the time. It happened when you went from a single fertilized zygote to two cells, to four, eight, sixteen and onwards until you were several trillion cells worth of newborn baby. It continues to happen as old cells divide to form replacement cells. Each time, the DNA faithfully replicates. DNA replicates so easily and accurately because of those As, Gs, Cs, and Ts we discussed a moment ago. A double stranded DNA molecule is unwound by enzymes, and the hydrogen bonds connecting the complementary base pairs are broken. What results are two template strands that have so-called sticky ends. Free floating nucleotide base pairs in the nucleus of the cell (which are acquired through the foods we eat- which have their own DNA), bind to the template strands following the rule of base pairs: A goes with T and C goes with G. In this case CTAT is separated from GATA. These sticky ends become templates to form two new strands that are identical to one another. Again, it is the very structure of DNA that explains how copies of it can be made. We often say that the replication process produces identical copies of DNA, but that is not entirely true. Copying mistakes can occasionally occur- yet another source for genetic variation.

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Copyright ©2013 W.W. Norton, Inc.

Chromosome Types

  • Homologous pairs
  • Autosomes (22 pairs)
  • Sex chromosomes (1 pair)
  • X and Y
  • Male determines sex
  • Karyotype

Before we get into the nuts and bolts of mitosis, let’s consider those chromosomes one last time. In order to make sure that each copy of the full sequence of DNA gets into each cell, the chromosomes must pair up and replicate. 23 of these chromosomes were inherited from the mother, and 23 from the father and each chromosome number (1 to 23) are different in their length and the genes they contain. These chromosomes pair up into matching, or homologous pairings, in the somatic cells. Though these chromosome pairs (shown in the top image) may look identical, they may very well contain different versions of a gene (known as alleles), since one chromosome was inherited from the mother and the other from the father. 22 of the 23 homologous pairs of chromosomes are what are referred to as autosomes. The other pair determines the sex of the individual and are appropriately named the sex chromosomes X and Y. Females have two X chromosomes, one inherited from their mother and one from their father. Males have an X and a Y—the X from their mother and the Y from their father. Because females have two X chromosomes, they can only contribute an X in the egg cell they produce. Because the male has both an X and a Y, there is a 50-50 chance that a sperm will contain an X or a Y. It is therefore true that the male “determines” the sex of a child by either contributing an X (and therefore producing a female) or a Y (and therefore producing a male), though of course this is not a conscious decision the sperm cells make. One way to visualize the homologous chromosomes is to produce what is called a karyotype—this is shown in the bottom right of the slide. Notice the 22 homologous pairs of autosomes numbered according to their size, and last the sex chromosomes. Based on what you see here, is this karyotype from a female or a male?

LET THE STUDENTS THINK ABOUT THIS AND THEN DISCUSS (THIS IS A FEMALE KARYOTYPE SINCE THERE ARE TWO X CHROMOSOMES)

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Copyright ©2013 W.W. Norton, Inc.

Mitosis

You started as a single fertilized egg, called a zygote. It had 46 chromosomes. Cells with this full set of chromosomes (46) are called diploid. As we’ll soon see, cells with half the number of chromosomes (23) are called haploid. These are the egg and sperm cells, and there is a very obvious reason that they have half the number of chromosomes, which we’ll encounter in just a moment. But, back to that zygote. During embryological development, this little zygote divided to form 2, 4, 8, 16, 32, 64, and eventually trillions of cells. These cells soon form tissues and organs in a process known as embryological development. If the DNA divided as the cells do, your chromosomes would go from 46 to 23 to 11.5 to 5.75. Of course, this did not happen. Instead, every cell contains 46 chromosomes. This occurs because, as we already discussed, DNA can replicate itself and does so before each cell division so that the cell goes from 46 chromosome to 92 before dividing into two cells, each with 46 chromosomes. The process by which this occurs is called mitosis.

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Copyright ©2013 W.W. Norton, Inc.

Mitosis

As shown in this figure, mitosis starts with a single diploid cell that has 23 pairs or homologous chromosomes (or 46 chromosomes). These chromosomes duplicate by unwinding their DNA and attaching free nucleotide bases to the template strands in the manner already discussed. After chromosome duplication, the cells technically have 92 chromosomes, which all line up in the middle of the cells so that one full set is on one side and another full set is on the other side of the cell midline. The cell pulls apart into two daughter cells, each with identical DNA. The microscopic image is of skin cells dividing into two daughter cells. Each of these cells has 23 pairs of homologous chromosomes (or 46 total).

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Meiosis

  • Haploid—23 chromosomes (no pairs)
  • Recombination via crossing-over
  • Haplotypes

Translocations and nondisjunctions

If an egg cell had 46 chromosomes and a sperm had 46 chromosomes, the resulting zygote would have 92 chromosomes. This simply would not work. So, gametes have to divide up the DNA a bit differently than somatic cells do. Instead of having a full copy of the organism’s DNA, gametes are haploid, meaning they only contain one chromosome from each pair of chromosomes. This one can be inherited from the mother or the one inherited from the father. With 23 chromosomes, the number of different combinations is exceptionally high, meaning that each egg and each sperm cell contains a unique combination of genes from the organisms’ mother and father. The process by which this occurs is called meiosis. Meiosis starts the same way as mitosis. The DNA replicates and the homologous chromosomes pair up. The cells then divide into two identical daughter cells, just as happens in mitosis. However, unlike mitosis, the cells then divide again, resulting in four daughter cells each with 23 chromosomes, but no pairs. Right before that final cell division, the homologous chromosomes can recombine their chromosomes in a process called crossing-over. A chunk of chromosome 2 from the mother’s line can switch with a chunk of chromosome 2 from the father’s line. So, not only are the 23 chromosomes in the gametes a random assortment of chromosomes from the mother and from the father, but within each chromosome there will be a combination of genes from the individual’s mother and father. Genes that are close together on a chromosome therefore tend to move together and cluster together. These clusters of genes are called haplotypes, which can be used to assess the history of genetic lineages. If chunks of DNA are exchanged on non-homologous chromosomes (called translocations) diseases such as leukemia can result. If the chromosomes fail to divide, the resulting gametes can have too few or too many chromosomes. Too few can result in a monosomy, and too many, a trisomy. Down syndrome is an example of a trisomy, in which there are three rather than two copies of chromosome 21.

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Copyright ©2013 W.W. Norton, Inc.

Law of Independent Assortment

We’ve obviously been learning about genetics. But, in the last chapter, we learned about Mendel and his genetics experiments on pea plants. What do the two have to do with each other? This is a very important slide that demonstrates how these concepts are linked to one another. Here is another Punnett square in which two pea plants with identical genotypes and phenotypes are crossed. Each plant has yellow seeds in a green pod, and each plant is heterozygous. Remember that this means that both plants have each allele for pod color and seed color, but that the dominant allele is expressed. Breeding identical plants together like this, most would expect that the offspring should be identical to their parents, but genetics does not work that way. During meiosis, the top pea plant will produce a gamete with either big G or little g combined with either big Y or little y. Each has an equal chance of being produced resulting in four possible combinations of genes in the gametes: GY, Gy, gY, and gy. The same applies for the plant on the left of the Punnett square. Now, when these gametes are combined together in all possible ways to produce zygotes, the resulting baby plants will have the genotypes shown on the Punnett square, and a 9:3:3:1 ratio of phenotypes. Nine will have green pods and yellow seeds like the parents, three will have green pods and green seeds, three will have yellow pods and yellow seeds, and one will have yellow pods and green seeds (the exact OPPOSITE of what the parents had!). Notice that having one particular color of pea pod had nothing to do with the color of the seed. This is known as the law of independent assortment. Notice also that the rules of genetics and the process of meiosis produces plentiful variation—the raw material for natural selection to act on.

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Copyright ©2013 W.W. Norton, Inc.

Law of Independent Assortment

But, those are pea plants. What about humans? Here is an example that applies more to you and I. Suppose the gene for hair color is on the small chromosome and the gene for eye color is on the large chromosome. The blue allele on the small chromosome represents blond hair and on the large chromosome represents blue eyes. The red allele on the small chromosome represents brown hair and on the large chromosome brown eyes. Both parents are heterozygous and, we’ll say for argument sake, brown eyes and hair are dominant, meaning that both parents have brown hair and brown eyes. The parent on the left, we’ll call a female, produces four eggs through meiosis. Because of the law of independent assortment, the alleles for hair and eye color are independent from one another, producing two eggs that pass on the alleles for brown hair and brown eyes and two eggs with the alleles for blond hair and blue eyes. Just as likely is what happens with the male. He produces four sperm cells, two with brown eyes and blond hair and two with blue eyes and brown hair. Choose one egg and one sperm and combine them together. What do you get? Now choose another? Notice that there will be a mixture of these features. Some of the offspring will have blond hair and brown eyes; some will have brown hair and blue eyes. Keep in mind that these combinations were not present in the parents.

Some of you may be saying that hair color and eye color are NOT independent; that they do seem to be present together (brown with brown; blond with blue). You are of course right. One of the reasons for this is that some of the genes that code for these traits are in fact on the same chromosome. The bottom image shows how genes close to one another on the same chromosome will not follow the law of independent assortment and will instead by linked to one another. This is called linkage.

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Copyright ©2013 W.W. Norton, Inc.

DNA and Protein Synthesis

But, how does DNA cause a seed to be yellow or hair to be brown? When we talk about DNA as a code, what do we actually mean? Besides replicating itself, the other critically important thing DNA does is to code for proteins. Proteins are what bodies are made of. There are seven types of proteins described here. Some, called enzymes, help with chemical reactions, such as the protein lactase that helps break down the lactose sugar in milk. Others are structural proteins, like the keratin that makes up our hair and nails, or the collagen that helps make up bone—these are shown in this image to the right. There are gas transport proteins like hemoglobin, which transports oxygen throughout the body. Antibodies, which help fight diseases, are proteins. Hormones like insulin, which helps regulate the metabolism of sugar and fats in the body are proteins. Muscles are comprised of the mechanical proteins actin and myosin. Finally, protein can be of the nutrient-form, like ovalbumin, which is found in egg whites. Proteins are critical for the normal functioning of an organism. So, how does DNA code for these proteins? First, it is important to recognize that proteins are made of amino acids. There are 20 different kinds of amino acids; 12 of these humans can manufacture; the other 8 have to be eaten and are therefore called essential amino acids. These 20 different amino acids can combine together into chains of various lengths and different properties. These properties are what makes a protein like keratin different from a protein like hemoglobin.

Copyright ©2013 W.W. Norton, Inc.

Transcription and Translation

  • Transcription
  • DNA transcribed into mRNA in the nucleus of the cell
  • Translation
  • mRNA translated into amino acid chain at the ribosomes

Protein synthesis, or the process by which a DNA code is turned into a chain of amino acids, occurs in cells. First the DNA code is read by enzymes, producing a molecule called messenger RNA. This process, in which messenger RNA is created from a DNA code is called transcription. The messenger RNA then leaves the nucleus of the cell and enters the cytoplasm. It binds to ribosomes, which are organelles that facilitate the translation of messenger RNA into a chain of amino acids, which ultimately form a protein. Let’s look in more detail how this actually happens.

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Copyright ©2013 W.W. Norton, Inc.

Transcription

Just like during DNA replication, the DNA is unwound, or unzipped, by enzymes. However, unlike replication, only one of the strands of DNA is used during transcription. Also, unlike replication, only a specific section of the DNA is unwound; this region is called a gene. The unwound DNA strand serves as a template for making a single-stranded molecule of messenger RNA. RNA is very similar to DNA, but instead of using A, G, C, and T as base pairs, RNA uses A, G, C, and U. U stands for Uracil and it binds to adenine (A), just like thymine (T) does in DNA. As is shown here, if the gene has the sequence TACTC, the messenger RNA molecule will be AUGAG and so on. Once the gene is fully transcribed, the messenger RNA molecule leaves the nucleus and finds ribosomes in the cytoplasm of the cell.

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Copyright ©2013 W.W. Norton, Inc.

Translation

Once messenger RNA binds to a ribosome, translation of the code into amino acids can begin. This process occurs in threes. Three nucleotides, called a codon, are read by the ribosome. These are “read” by matching a complementary anticodon to the codon. For instance, if the messenger RNA codon is AUG, then the anticodon has to be UAC since those are the three nucleotides that are complementary to the codon. Importantly, these anticodons are attached to a specific amino acid, in this case methionine, in a structure called a transfer RNA (tRNA). The next three nucleotides in the codon are AGU, which match with the anticodon UCA, which is attached to the amino acid serine. This goes on and one, in groups of three, until the last codon (UAG) , which is the stop sequence. The amino acid chain is then released into the cytoplasm. The amino acid chain folds into a three-dimensional structure, or bonds with other 3-D proteins, which give these proteins their specific properties. What we have described here happens in only a small percentage of the human genome. In fact, only about 5% of the total genome is composed of structural genes that code for proteins, or regulatory genes that turn genes on and off. We will turn to these genes next.

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Copyright ©2013 W.W. Norton, Inc.

Regulatory Genes

  • On/off switches for genes
  • Marfan syndrome
  • Chicken teeth
  • Human hair
  • Lactose intolerance or persistence

Regulatory genes can be thought of as on/off switches, or, perhaps more accurately, dimmer switches. Regulatory genes determine if a gene is on or off, and can regulate the amount of protein produced, and when. For instance, if the genes controlling connective tissue growth are left on a bit longer during development, what can result are longer, thinner fingers as is shown in this image. This is characteristic of a disease called Marfan syndrome. Regulatory genes have also allowed us to understand major evolutionary events. For instance, paleontological evidence demonstrates that modern birds evolved from a group of feathered dinosaurs. But, anyone who has visited a science museum knows that dinosaurs have teeth. Birds do not. Where did their teeth go? Scientists have recently discovered that birds still have the structural genes to make teeth. But, the regulatory genes controlling those structural genes have been turned off. A similar thing has happened with human body hair. Humans have less body hair than other primates. We still have the genes for full body hair coverage, but these genes have been down-regulated. Similarly, all baby mammals have the ability to digest milk. This is because they produce the enzyme lactase, which breaks down lactose. However, these genes are turned off in most adult mammals. However, some humans have lactose persistence, meaning that the genes are not turned off and they can continue to digest milk as adults. Those who retain the typical mammalian condition of losing lactase production into adulthood are said to be lactose intolerant. Notice that natural selection can act upon the products of structural genes, but can also operate on the products of variation in regulatory genes. In fact, research on human and chimpanzee genomes have discovered that while our structural genes are very similar, there are important differences in those regulatory genes.

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Copyright ©2013 W.W. Norton, Inc.

Homeotic (Hox) Genes

One of the best examples of regulatory genes are those of the homeotic, or Hox, family of genes. These are master switches that determine the general form of an animal’s body. Notice that whether you are a human, a mouse, or a fruit fly, heads are where heads should be, bodies are where bodies should be, and limbs are where limbs should be. Why is this? Researchers have discovered that a group of genes, called Hox genes, regulate the position of the major body parts during embryological development. What was amazing to researchers was that the very same genes regulate this process of body formation in organisms as different as flies, mice, and humans. Small changes in how long these genes are switched on, or where they are expressed, can result in differences in overall body form. For instance, the genes for the neck region are positioned differently in birds and snakes giving bird long necks and snakes short necks (but long bodies). The Hox genes that determine forelimb and finger length are switched on for a longer period of development in bats, compared to other mammals. Again, selection can favor the products of variation in regulatory genes as effectively as structural genes.

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Law of Segregation and Codominance

Let’s look at one more Punnett square to consider how variations in specific genes can result in even more possible combinations of traits. As we have already discussed, the mother and father contribute equally to the genetic makeup of the offspring. This is known as the Law of segregation. Consider this example in which a pure red sweet pea is crossed with a pure white sweet pea. The offspring in the first generation will all be heterozygous, meaning that they will inherit the red allele from one parent and the white allele from the other. If the resulting flowers are all red, then the red allele is said to be dominant over the white allele. But, what if the flowers are all pink? This can happen, it means that these two alleles are both expressed, neither is dominant over the other, and they are said to be codominant. If these flowers care crossed, the offspring will be a combination of pure red (genotype big R big R), pure white (genotype little r little r), and pink, or shown here as hybrid white.

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Copyright ©2013 W.W. Norton, Inc.

Polymorphisms: Variations in Specific Genes

  • Exercises:
  • Can mother with blood type A and father with blood type B have a baby with blood type O?
  • Can a man with blood type AB be the father of a baby with blood type O?

Let’s apply these principles to humans again. Human blood type is a great example of a trait with multiple alleles. A person can be blood type O, A, B, or AB. Because there can be more than one kind of blood type, this is referred to as a polymorphic trait. But, what do these blood types mean in terms of genetics? Every person has two blood type alleles (one from mom and one from dad). These can be allele A, B, or O. The A allele codes for a protein that we call A. The B allele codes for a protein that we call B. If someone has the A allele on one chromosome and the B allele on the other, they are blood type AB. This is because these alleles are codominant and both blood proteins are produced. So, do people with the O allele make an O protein? No. In fact, they do not make a protein at all. This is why the O blood type is referred to as the universal donor. Because there are no proteins on the surface of the cells, the recipient of this blood type will not attack these cells. Someone with blood type AB does not make antibodies against either A or B, and therefore can receive blood from any blood type. However, someone with blood type A will make antibodies against B and cannot receive that blood type without fatal complications. Likewise, someone with blood type O makes antibodies against all other blood types, and cannot receive any other blood type except O. Let’s look at this again in the context of genetics. Can parents with blood type A and blood type B have a baby with blood type O? The answer is yes. Draw a Punnett square to try to work this out. Can either of the parents be homozygous, or must they both be heterozygous? Try this one: Can a man with blood type AB be the father of a child with blood type O? Why or why not?

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Copyright ©2013 W.W. Norton, Inc.

Polygenic Traits and Pleiotropy

  • Many traits polygenic
  • Height, skin color
  • Many genes pleiotropic
  • Sickle-cell
  • All traits a product of genes AND environment
  • Height and nutrition

By this point, you are probably realizing that genetics is complicated business. But, it is MUCH more complicated than I’ve described in this lecture. Many traits are polygenic, meaning that multiple genes are responsible for the phenotype observed. For instance, a person’s height, or skin coloration can be influenced by hundreds of different genes. In addition, these and many other traits can be highly influenced by the environment. For instance, height can be strongly impacted by nutrition. Remember that natural selection can only work on traits that are passed from generation to generation, so quantifying the role that genetics has in shaping a particular phenotype can be quite important in determining the role of natural selection in shaping it. Complicating matters even further is the reality that the same gene can influence many different phenotypes. The sickle-cell gene, for instance, influences both the individual’s ability to combat malaria as well as the ability to transport oxygen through the body. It turns out, most traits are both polygenic and pleiotropic (modeled on the bottom right), making genetics a fascinating, but quite complicated, science.

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Copyright ©2013 W.W. Norton, Inc.

Genetics: Reproducing

Life and Producing Variation

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Clark • Spencer • Larsen

Essentials of Physical Anthropology

Second Edition

CHAPTER

This concludes the Lecture PowerPoint presentation for:

3

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StudySpace site for Essentials of Physical Anthropology
http://books.wwnorton.com/studyspace

The last chapter ended with a brief introduction to DNA. But, what is DNA? What is it made of? And how can a small molecule like DNA ‘code’ for all of the traits in a living organism? We will address these and other questions in this chapter. Ultimately, what we are doing in this chapter is understanding how the genetic code (DNA) results in variation, because it is this variation that natural selection can act upon and lead to evolutionary changes. We will start by looking at the fundamental unit of all life on Earth: the cell. Inside each cell, the DNA code is structured into packages known as chromosomes. We will see how the DNA molecule can copy itself so that each cell in an organism’s body contains the same DNA information. We will then look at how DNA codes for proteins, which all living organisms are made of. Finally, we will look at a concrete example of how DNA impacts our lives by examining human blood types. Though we have to dive into the microscopic world, do not lose sight of the big picture: DNA is a code for making proteins, and we are made of proteins. If the DNA slightly changes (through mutation, which we met in the last chapter), the protein changes, and thus the organism can change.

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All living organisms are made of cells; they are the basic units of life. There are many, many organisms that are made of just one cell, and many (including you) that are made of trillions of cells. All of life can be divided into two big categories, depending on the kind of cell they have. The first kind are organisms called prokaryotes. Prokaryotes are single-celled bacteria without nuclei or any special structures called organelles. They often have structures shown here in this image, like a cell wall, an outer membrane, a cytoplasm within which the DNA resides, and they often have locomotor structures like a flagellum. On this slide is a microscopic image of a prokaryotic cell that we have all heard of: Escherichia coli (E. coli), which lives in the guts of many mammals, including humans. Though prokaryotic cells live within us, and have been instrumental factors in driving human evolution, we will turn now to the cells we are made of: eukaryotic cells.

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All animals, plants, fungi, and many single-celled organisms called protists are made of eukaryotic cells. These cells have a nucleus that contains DNA, and often have membrane-bound parts of the cell called organelles. These include chloroplasts (found in plants) and mitochondria, which help produce the molecular energy that powers cellular processes. Notice in this image that the eukaryotic cell is a bit more complicated than a prokaryotic cell. The microscopic image here is of kidney cells, which clearly have a nucleus, a membrane keeping the components of the cell contained, and a fluid within the cell called a cytoplasm.

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There are two types of eukaryotic cells in all animals and plants: somatic cells and gametes. Somatic cells, also called body cells, are found all over the body. Shown in the above image are the somatic cells found in the (clockwise from top left) brain, blood, bone, and skin. Somatic cells all contain a complete copy of the organism’s DNA. For example, in humans, somatic cells have all of the DNA packed in 46 chromosomes. Somatic cells also replicate through a process called mitosis, which we will learn about in just a moment. At the bottom right is an image of the other kind of eukaryotic cells: gametes. The large round cell is called an egg, or an ova. The small wiggly structures surrounding the egg are sperm. These are gametes. They contain only half of the organism’s DNA (23 chromosomes in humans) and replicate through a process known as meiosis.

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Since we just mentioned chromosomes, it is worth examining chromosome number in a bit more detail. Humans have 46 chromosomes in our somatic cells. 23 of these came from our mother, and 23 from our father, for a grand total of 46. But, this number, 46, is not special at all. Other apes, like chimpanzees, have 48 chromosomes. Some primates have fewer chromosomes, like the colobus monkey which has 44. Some organisms we would consider to be less complex than us have fewer chromosomes, like the house fly with 12 or the salamander with 24. But, plenty of organisms have more than we have, like the potato with 48, the camel with 70, or algae, which has 148 chromosomes. Classifying organisms by the number of chromosomes they have would be like organizing books in a library based on the number of pages they have, or by the color of its jacket cover. It wouldn’t make sense. What matters are not the number of chromosomes an organism has, but the similarity in DNA that is packaged in the chromosomes. For instance, humans and chimpanzees share about 98% of their DNA. This is remarkable, and, in some ways, indicates how important 2% of a difference can be.

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Most likely, you have all heard of DNA, and have probably heard that it is the “blueprint,” or “recipe,” or “code” for life? But, how does this work? It helps first to understand the structure of DNA, and to understand how it is packaged in your cells. It is estimated that there is six feet worth of DNA in every cell in your body. Six feet!? If cells are microscopic, how can this be? As shown in this image, the DNA molecule is wound up into compact structures that we have already encountered: chromosomes. Sections of that DNA specifically code for a specific protein in the body: These are called genes. The genome is all of the genes put together in all of the chromosomes. The DNA that is in the nucleus of our cells is called homoplasmic, meaning it is more or less the exact same in every cell in our body. But, the nucleus is not the only place in a cell that contains DNA. An organelle called the mitochondria also contains DNA. Mitochondrial DNA (mtDNA) is much, much smaller; it only contains 37 genes. And these genes are only inherited from your mother, meaning they can be used to trace one’s maternal lineage (called a matriline). Unlike nuclear DNA, mitochondrial DNA can differ from cell to cell, making it heteroplasmic.

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We are finally ready to discuss what DNA actually is. It is a molecule; in fact, a very simple one. DNA is made of three things: a type of sugar, a phosphate group, and a nucleotide base pair. The sugar and phosphate form the backbone of the long DNA molecule and these do not vary along the chain. What varies along the chain are the nucleotide base pairs. These bases can be one of four types: adenine (A), thymine (T), guanine (G) and cytosine (C). You can think of DNA as a ladder with the sugar and phosphates forming the uprights, and the bases forming the rungs. The rungs are made of two base pairs that cling together using hydrogen bonds. Critical to understanding DNA is the fact that the base pairs do not randomly cling to each other. Instead, A only clings to T, and C only clings to G. These are called complementary bases. What this means is, if you know one side of the DNA chain, you know the other. If a DNA sequence is CAAAT, the other side MUST be GTTTA. Though any two humans may have over 99% of their DNA base pair order identical, there are, of course, differences. Differences in these single nucleotide regions are called SNPs (pronounced “snips” and short for single nucleotide polymorphisms). These are some of the areas of the genome that can be used to solve crimes using DNA evidence since they can vary from one individual to another.

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The very structure of DNA explains how it is so easily, and so accurately, replicated. When a cell is going to divide, it copies its entire genome. Remember those nucleotide base pairs? Well, there are 3 billion of them to copy each time a cell divides. And cells divide all the time. It happened when you went from a single fertilized zygote to two cells, to four, eight, sixteen and onwards until you were several trillion cells worth of newborn baby. It continues to happen as old cells divide to form replacement cells. Each time, the DNA faithfully replicates. DNA replicates so easily and accurately because of those As, Gs, Cs, and Ts we discussed a moment ago. A double stranded DNA molecule is unwound by enzymes, and the hydrogen bonds connecting the complementary base pairs are broken. What results are two template strands that have so-called sticky ends. Free floating nucleotide base pairs in the nucleus of the cell (which are acquired through the foods we eat- which have their own DNA), bind to the template strands following the rule of base pairs: A goes with T and C goes with G. In this case CTAT is separated from GATA. These sticky ends become templates to form two new strands that are identical to one another. Again, it is the very structure of DNA that explains how copies of it can be made. We often say that the replication process produces identical copies of DNA, but that is not entirely true. Copying mistakes can occasionally occur- yet another source for genetic variation.

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Before we get into the nuts and bolts of mitosis, let’s consider those chromosomes one last time. In order to make sure that each copy of the full sequence of DNA gets into each cell, the chromosomes must pair up and replicate. 23 of these chromosomes were inherited from the mother, and 23 from the father and each chromosome number (1 to 23) are different in their length and the genes they contain. These chromosomes pair up into matching, or homologous pairings, in the somatic cells. Though these chromosome pairs (shown in the top image) may look identical, they may very well contain different versions of a gene (known as alleles), since one chromosome was inherited from the mother and the other from the father. 22 of the 23 homologous pairs of chromosomes are what are referred to as autosomes. The other pair determines the sex of the individual and are appropriately named the sex chromosomes X and Y. Females have two X chromosomes, one inherited from their mother and one from their father. Males have an X and a Y—the X from their mother and the Y from their father. Because females have two X chromosomes, they can only contribute an X in the egg cell they produce. Because the male has both an X and a Y, there is a 50-50 chance that a sperm will contain an X or a Y. It is therefore true that the male “determines” the sex of a child by either contributing an X (and therefore producing a female) or a Y (and therefore producing a male), though of course this is not a conscious decision the sperm cells make. One way to visualize the homologous chromosomes is to produce what is called a karyotype—this is shown in the bottom right of the slide. Notice the 22 homologous pairs of autosomes numbered according to their size, and last the sex chromosomes. Based on what you see here, is this karyotype from a female or a male?

 

LET THE STUDENTS THINK ABOUT THIS AND THEN DISCUSS (THIS IS A FEMALE KARYOTYPE SINCE THERE ARE TWO X CHROMOSOMES)

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You started as a single fertilized egg, called a zygote. It had 46 chromosomes. Cells with this full set of chromosomes (46) are called diploid. As we’ll soon see, cells with half the number of chromosomes (23) are called haploid. These are the egg and sperm cells, and there is a very obvious reason that they have half the number of chromosomes, which we’ll encounter in just a moment. But, back to that zygote. During embryological development, this little zygote divided to form 2, 4, 8, 16, 32, 64, and eventually trillions of cells. These cells soon form tissues and organs in a process known as embryological development. If the DNA divided as the cells do, your chromosomes would go from 46 to 23 to 11.5 to 5.75. Of course, this did not happen. Instead, every cell contains 46 chromosomes. This occurs because, as we already discussed, DNA can replicate itself and does so before each cell division so that the cell goes from 46 chromosome to 92 before dividing into two cells, each with 46 chromosomes. The process by which this occurs is called mitosis.

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As shown in this figure, mitosis starts with a single diploid cell that has 23 pairs or homologous chromosomes (or 46 chromosomes). These chromosomes duplicate by unwinding their DNA and attaching free nucleotide bases to the template strands in the manner already discussed. After chromosome duplication, the cells technically have 92 chromosomes, which all line up in the middle of the cells so that one full set is on one side and another full set is on the other side of the cell midline. The cell pulls apart into two daughter cells, each with identical DNA. The microscopic image is of skin cells dividing into two daughter cells. Each of these cells has 23 pairs of homologous chromosomes (or 46 total).

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If an egg cell had 46 chromosomes and a sperm had 46 chromosomes, the resulting zygote would have 92 chromosomes. This simply would not work. So, gametes have to divide up the DNA a bit differently than somatic cells do. Instead of having a full copy of the organism’s DNA, gametes are haploid, meaning they only contain one chromosome from each pair of chromosomes. This one can be inherited from the mother or the one inherited from the father. With 23 chromosomes, the number of different combinations is exceptionally high, meaning that each egg and each sperm cell contains a unique combination of genes from the organisms’ mother and father. The process by which this occurs is called meiosis. Meiosis starts the same way as mitosis. The DNA replicates and the homologous chromosomes pair up. The cells then divide into two identical daughter cells, just as happens in mitosis. However, unlike mitosis, the cells then divide again, resulting in four daughter cells each with 23 chromosomes, but no pairs. Right before that final cell division, the homologous chromosomes can recombine their chromosomes in a process called crossing-over. A chunk of chromosome 2 from the mother’s line can switch with a chunk of chromosome 2 from the father’s line. So, not only are the 23 chromosomes in the gametes a random assortment of chromosomes from the mother and from the father, but within each chromosome there will be a combination of genes from the individual’s mother and father. Genes that are close together on a chromosome therefore tend to move together and cluster together. These clusters of genes are called haplotypes, which can be used to assess the history of genetic lineages. If chunks of DNA are exchanged on non-homologous chromosomes (called translocations) diseases such as leukemia can result. If the chromosomes fail to divide, the resulting gametes can have too few or too many chromosomes. Too few can result in a monosomy, and too many, a trisomy. Down syndrome is an example of a trisomy, in which there are three rather than two copies of chromosome 21.

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We’ve obviously been learning about genetics. But, in the last chapter, we learned about Mendel and his genetics experiments on pea plants. What do the two have to do with each other? This is a very important slide that demonstrates how these concepts are linked to one another. Here is another Punnett square in which two pea plants with identical genotypes and phenotypes are crossed. Each plant has yellow seeds in a green pod, and each plant is heterozygous. Remember that this means that both plants have each allele for pod color and seed color, but that the dominant allele is expressed. Breeding identical plants together like this, most would expect that the offspring should be identical to their parents, but genetics does not work that way. During meiosis, the top pea plant will produce a gamete with either big G or little g combined with either big Y or little y. Each has an equal chance of being produced resulting in four possible combinations of genes in the gametes: GY, Gy, gY, and gy. The same applies for the plant on the left of the Punnett square. Now, when these gametes are combined together in all possible ways to produce zygotes, the resulting baby plants will have the genotypes shown on the Punnett square, and a 9:3:3:1 ratio of phenotypes. Nine will have green pods and yellow seeds like the parents, three will have green pods and green seeds, three will have yellow pods and yellow seeds, and one will have yellow pods and green seeds (the exact OPPOSITE of what the parents had!). Notice that having one particular color of pea pod had nothing to do with the color of the seed. This is known as the law of independent assortment. Notice also that the rules of genetics and the process of meiosis produces plentiful variation—the raw material for natural selection to act on.

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But, those are pea plants. What about humans? Here is an example that applies more to you and I. Suppose the gene for hair color is on the small chromosome and the gene for eye color is on the large chromosome. The blue allele on the small chromosome represents blond hair and on the large chromosome represents blue eyes. The red allele on the small chromosome represents brown hair and on the large chromosome brown eyes. Both parents are heterozygous and, we’ll say for argument sake, brown eyes and hair are dominant, meaning that both parents have brown hair and brown eyes. The parent on the left, we’ll call a female, produces four eggs through meiosis. Because of the law of independent assortment, the alleles for hair and eye color are independent from one another, producing two eggs that pass on the alleles for brown hair and brown eyes and two eggs with the alleles for blond hair and blue eyes. Just as likely is what happens with the male. He produces four sperm cells, two with brown eyes and blond hair and two with blue eyes and brown hair. Choose one egg and one sperm and combine them together. What do you get? Now choose another? Notice that there will be a mixture of these features. Some of the offspring will have blond hair and brown eyes; some will have brown hair and blue eyes. Keep in mind that these combinations were not present in the parents.

Some of you may be saying that hair color and eye color are NOT independent; that they do seem to be present together (brown with brown; blond with blue). You are of course right. One of the reasons for this is that some of the genes that code for these traits are in fact on the same chromosome. The bottom image shows how genes close to one another on the same chromosome will not follow the law of independent assortment and will instead by linked to one another. This is called linkage.

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But, how does DNA cause a seed to be yellow or hair to be brown? When we talk about DNA as a code, what do we actually mean? Besides replicating itself, the other critically important thing DNA does is to code for proteins. Proteins are what bodies are made of. There are seven types of proteins described here. Some, called enzymes, help with chemical reactions, such as the protein lactase that helps break down the lactose sugar in milk. Others are structural proteins, like the keratin that makes up our hair and nails, or the collagen that helps make up bone—these are shown in this image to the right. There are gas transport proteins like hemoglobin, which transports oxygen throughout the body. Antibodies, which help fight diseases, are proteins. Hormones like insulin, which helps regulate the metabolism of sugar and fats in the body are proteins. Muscles are comprised of the mechanical proteins actin and myosin. Finally, protein can be of the nutrient-form, like ovalbumin, which is found in egg whites. Proteins are critical for the normal functioning of an organism. So, how does DNA code for these proteins? First, it is important to recognize that proteins are made of amino acids. There are 20 different kinds of amino acids; 12 of these humans can manufacture; the other 8 have to be eaten and are therefore called essential amino acids. These 20 different amino acids can combine together into chains of various lengths and different properties. These properties are what makes a protein like keratin different from a protein like hemoglobin.

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Protein synthesis, or the process by which a DNA code is turned into a chain of amino acids, occurs in cells. First the DNA code is read by enzymes, producing a molecule called messenger RNA. This process, in which messenger RNA is created from a DNA code is called transcription. The messenger RNA then leaves the nucleus of the cell and enters the cytoplasm. It binds to ribosomes, which are organelles that facilitate the translation of messenger RNA into a chain of amino acids, which ultimately form a protein. Let’s look in more detail how this actually happens.

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Just like during DNA replication, the DNA is unwound, or unzipped, by enzymes. However, unlike replication, only one of the strands of DNA is used during transcription. Also, unlike replication, only a specific section of the DNA is unwound; this region is called a gene. The unwound DNA strand serves as a template for making a single-stranded molecule of messenger RNA. RNA is very similar to DNA, but instead of using A, G, C, and T as base pairs, RNA uses A, G, C, and U. U stands for Uracil and it binds to adenine (A), just like thymine (T) does in DNA. As is shown here, if the gene has the sequence TACTC, the messenger RNA molecule will be AUGAG and so on. Once the gene is fully transcribed, the messenger RNA molecule leaves the nucleus and finds ribosomes in the cytoplasm of the cell.

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Once messenger RNA binds to a ribosome, translation of the code into amino acids can begin. This process occurs in threes. Three nucleotides, called a codon, are read by the ribosome. These are “read” by matching a complementary anticodon to the codon. For instance, if the messenger RNA codon is AUG, then the anticodon has to be UAC since those are the three nucleotides that are complementary to the codon. Importantly, these anticodons are attached to a specific amino acid, in this case methionine, in a structure called a transfer RNA (tRNA). The next three nucleotides in the codon are AGU, which match with the anticodon UCA, which is attached to the amino acid serine. This goes on and one, in groups of three, until the last codon (UAG) , which is the stop sequence. The amino acid chain is then released into the cytoplasm. The amino acid chain folds into a three-dimensional structure, or bonds with other 3-D proteins, which give these proteins their specific properties. What we have described here happens in only a small percentage of the human genome. In fact, only about 5% of the total genome is composed of structural genes that code for proteins, or regulatory genes that turn genes on and off. We will turn to these genes next.

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Regulatory genes can be thought of as on/off switches, or, perhaps more accurately, dimmer switches. Regulatory genes determine if a gene is on or off, and can regulate the amount of protein produced, and when. For instance, if the genes controlling connective tissue growth are left on a bit longer during development, what can result are longer, thinner fingers as is shown in this image. This is characteristic of a disease called Marfan syndrome. Regulatory genes have also allowed us to understand major evolutionary events. For instance, paleontological evidence demonstrates that modern birds evolved from a group of feathered dinosaurs. But, anyone who has visited a science museum knows that dinosaurs have teeth. Birds do not. Where did their teeth go? Scientists have recently discovered that birds still have the structural genes to make teeth. But, the regulatory genes controlling those structural genes have been turned off. A similar thing has happened with human body hair. Humans have less body hair than other primates. We still have the genes for full body hair coverage, but these genes have been down-regulated. Similarly, all baby mammals have the ability to digest milk. This is because they produce the enzyme lactase, which breaks down lactose. However, these genes are turned off in most adult mammals. However, some humans have lactose persistence, meaning that the genes are not turned off and they can continue to digest milk as adults. Those who retain the typical mammalian condition of losing lactase production into adulthood are said to be lactose intolerant. Notice that natural selection can act upon the products of structural genes, but can also operate on the products of variation in regulatory genes. In fact, research on human and chimpanzee genomes have discovered that while our structural genes are very similar, there are important differences in those regulatory genes.

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One of the best examples of regulatory genes are those of the homeotic, or Hox, family of genes. These are master switches that determine the general form of an animal’s body. Notice that whether you are a human, a mouse, or a fruit fly, heads are where heads should be, bodies are where bodies should be, and limbs are where limbs should be. Why is this? Researchers have discovered that a group of genes, called Hox genes, regulate the position of the major body parts during embryological development. What was amazing to researchers was that the very same genes regulate this process of body formation in organisms as different as flies, mice, and humans. Small changes in how long these genes are switched on, or where they are expressed, can result in differences in overall body form. For instance, the genes for the neck region are positioned differently in birds and snakes giving bird long necks and snakes short necks (but long bodies). The Hox genes that determine forelimb and finger length are switched on for a longer period of development in bats, compared to other mammals. Again, selection can favor the products of variation in regulatory genes as effectively as structural genes.

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Let’s look at one more Punnett square to consider how variations in specific genes can result in even more possible combinations of traits. As we have already discussed, the mother and father contribute equally to the genetic makeup of the offspring. This is known as the Law of segregation. Consider this example in which a pure red sweet pea is crossed with a pure white sweet pea. The offspring in the first generation will all be heterozygous, meaning that they will inherit the red allele from one parent and the white allele from the other. If the resulting flowers are all red, then the red allele is said to be dominant over the white allele. But, what if the flowers are all pink? This can happen, it means that these two alleles are both expressed, neither is dominant over the other, and they are said to be codominant. If these flowers care crossed, the offspring will be a combination of pure red (genotype big R big R), pure white (genotype little r little r), and pink, or shown here as hybrid white.

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Let’s apply these principles to humans again. Human blood type is a great example of a trait with multiple alleles. A person can be blood type O, A, B, or AB. Because there can be more than one kind of blood type, this is referred to as a polymorphic trait. But, what do these blood types mean in terms of genetics? Every person has two blood type alleles (one from mom and one from dad). These can be allele A, B, or O. The A allele codes for a protein that we call A. The B allele codes for a protein that we call B. If someone has the A allele on one chromosome and the B allele on the other, they are blood type AB. This is because these alleles are codominant and both blood proteins are produced. So, do people with the O allele make an O protein? No. In fact, they do not make a protein at all. This is why the O blood type is referred to as the universal donor. Because there are no proteins on the surface of the cells, the recipient of this blood type will not attack these cells. Someone with blood type AB does not make antibodies against either A or B, and therefore can receive blood from any blood type. However, someone with blood type A will make antibodies against B and cannot receive that blood type without fatal complications. Likewise, someone with blood type O makes antibodies against all other blood types, and cannot receive any other blood type except O. Let’s look at this again in the context of genetics. Can parents with blood type A and blood type B have a baby with blood type O? The answer is yes. Draw a Punnett square to try to work this out. Can either of the parents be homozygous, or must they both be heterozygous? Try this one: Can a man with blood type AB be the father of a child with blood type O? Why or why not?

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By this point, you are probably realizing that genetics is complicated business. But, it is MUCH more complicated than I’ve described in this lecture. Many traits are polygenic, meaning that multiple genes are responsible for the phenotype observed. For instance, a person’s height, or skin coloration can be influenced by hundreds of different genes. In addition, these and many other traits can be highly influenced by the environment. For instance, height can be strongly impacted by nutrition. Remember that natural selection can only work on traits that are passed from generation to generation, so quantifying the role that genetics has in shaping a particular phenotype can be quite important in determining the role of natural selection in shaping it. Complicating matters even further is the reality that the same gene can influence many different phenotypes. The sickle-cell gene, for instance, influences both the individual’s ability to combat malaria as well as the ability to transport oxygen through the body. It turns out, most traits are both polygenic and pleiotropic (modeled on the bottom right), making genetics a fascinating, but quite complicated, science.

 
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Activity 7.6: Reading Contour Lines To effectively use topographic maps, familiarity with the rules for reading contour lines

8.1 Examining the Hydrologic Cycle

1. Sketch, label, and discuss the hydrologic cycle.

Earth’s water is constantly moving between Earth’s surface and atmosphere. The hydrologic cycle describes the continuous movement of water from the oceans to the atmosphere, from the atmosphere to the land, and from the land back to the sea. Over most of Earth, the quantity of precipitation that falls on the land must eventually be accounted for by the sum total of evaporation, transpiration (the release of water vapor by vegetation), runoff, and infiltration.

A portion of the precipitation that falls on land will soak into the ground through a process called infiltration. If the rate of rainfall exceeds the ability of the surface to absorb it, the additional water flows over the surface and becomes runoff. Runoff initially flows in broad sheets that form tiny channels called rills. The rills merge to form gullies, which eventually join to create streams. Erosion by both groundwater and running water wears down the land and shapes Earth’s surface.

Figure 8.1 illustrates Earth’s water balance, a quantitative view of the hydrologic cycle. The figure implies a globally uniform exchange of water between Earth’s atmosphere and surface, but factors such as climate, steepness of slope, surface materials, vegetation, and degree of urbanization produce local variations.

SmartFigure 8.1 Earth’s water balance, a quantitative view of the hydrologic cycle.

Watch

SmartFigure: The Water Cycle

Activity 8.1: Examining the Hydrologic Cycle

Use Figure 8.1 as a reference to complete the following:

1. Globally, from which source does more water evaporate into the atmosphere: oceans or land?

                                                                                                                                   

2. Approximately what percentage of the total water evaporated into the atmosphere comes from the oceans?

Percentage from oceans=Ocean evaporationTotal evaporation×100%=−−−−−−−−−−−−− %Percentage from oceans=Ocean evaporationTotal evaporation×100%=_ %

3. Notice in Figure 8.1 that more water evaporates from the oceans than is returned directly by precipitation. If sea level is not dropping, identify a source of water for the oceans in addition to precipitation.

                                                                                                                                   

4. Worldwide, about how much of the precipitation that falls on the land becomes runoff: 35, 55, or 75 percent?

About                                    % becomes runoff.

5. Much of the water that falls on land does not immediately return to the ocean via runoff. Instead, it is temporarily stored in reservoirs such as lakes. In some mountainous and polar regions, what features serve as reservoirs to temporarily store water?

                                                                                                                                   

6. Label the drawing in Figure 8.2 with the letters that correspond to the following terms:

Figure 8.2Illustration (cross section) of the hydrologic cycle.

9.3 Glaciers and Ice Sheets

1. Contrast alpine (valley) glaciers and ice sheets.

Present-day glaciers cover nearly 10 percent of Earth’s land area. At the height of the Quaternary Ice Age, glaciers were three times more extensive than they are today. These moving masses of ice create many unique landforms and are part of an important link in the rock cycle in which the products of weathering are transported and deposited as sediment.

A glacier is a thick ice mass that, over hundreds or thousands of years, forms on land as the yearly snowfall exceeds the quantity of ice lost by melting. A glacier appears to be motionless, but it is not; glaciers move very slowly. Thousands of glaciers exist in lofty mountain areas, where they usually follow valleys originally occupied by streams. Because of their settings, these moving ice masses are termed valley glaciers, or alpine glaciers.

Ice sheets (sometimes called continental glaciers) exist on a much larger scale than valley glaciers. These enormous masses flow out in all directions from one or more snow-accumulation centers and completely obscure all but the highest areas of underlying terrain. Presently each of Earth’s polar regions supports an ice sheet—Greenland in the Northern Hemisphere and Antarctica in the Southern Hemisphere.

Glacial erosion and deposition leave unmistakable imprints on Earth’s surface (Figure 9.5). In regions once covered by ice sheets, glacially scoured surfaces and subdued terrain dominate. By contrast, erosion caused by alpine glaciers accentuates the irregular mountainous topography, often producing spectacular scenery characterized by sharp, angular features. Glacial deposits are usually visible in both settings.

Figure 9.5Moving glacial ice, armed with sediment, acts like sandpaper, scratching and polishing rock and creating glacial striations.

(Photo by Michael Collier)

Activity 9.3: Glaciers and Ice Sheets

1. What percentage of Earth’s land surface do glaciers presently cover?

                          %

2. Identify two locations where ice sheets are currently found.

                                                                                                                                   

3. Briefly compare an ice sheet to a valley glacier.

                                                                                                                                   

Activity 9.6B: Identifying Glacial Features on a Topographic Map

Refer to Figure 9.13, a portion of the Holy Cross, Colorado, topographic map. This is a mountainous area that has been shaped by alpine glaciers.

Figure 9.13Holy Cross, Colorado

(Courtesy of U.S. Geological Survey)

1. Identify the glacial feature indicated by each of the following letters. Use Figure 9.12C as a reference.

· Letter A:                                                                                                      

· Letter B:                                                                                                     

2. A tarn is a lake that forms in a cirque. Of the features labeled C, D, E, and F, which indicate(s) a tarn(s)?

Letter(s):                                                                                                      

3. The feature marked G on the map is a depositional feature composed of glacial till. What type of glacial feature is it? How did it form?

                                                                                                                                   

                                                                                                                                   

4. Explain how Turquoise Lake likely formed.

                                                                                                                                   

                                                                                                                                   

5. Use Figure 9.14 to draw a topographic profile along the X–Y line from Sugar Loaf Mountain to Bear Lake and mark the position of the Lake Fork stream. (Use only index contours.)

Figure 9.14Topographic profile of the valley of Lake Fork on the Holy Cross, Colorado, map.

6. Describe the shape of Lake Fork Valley, based on your profile.

                                                                                                                                   

7. What glacial feature is Lake Fork Valley?

                                                                                                                                   

Mastering GeologyTM

Looking for additional review and lab prep materials? Go to www.masteringgeology.com for Pre-Lab Videos, Geoscience Animations, RSS Feeds, Key Term Study Tools, The Math You Need, an optional Pearson eText, and more.

 
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Please I Need This By Tomorrow At 1pm

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This is a physical science multiple choice test

Please I need this by 1pm I have attached the picture for question 1

1. It just so happens that regardless of the material, when objects are heated up they will start to glow and change colors at near identical temperatures. The plot that you see is called a blackbody spectrum. This plot tells us the intensity or the “amount” of light that an object will emit at different wavelengths (or “colors”). The visible wavelengths are marked by their colors on the plot. To the right of the visible band is lower energy infrared light. To the left of this band is higher energy ultraviolet (UV) light.

Click the + button that is to the left of the intensity scale (far left side of the screen) such that the top of the scale is at .001. (in the picture above the top of the scale says 100).

Now use the temperature slider to the right, and take the temperature all the way down to 300 Kelvin (80 Fahrenheit).

Now slowly begin to raise the temperature. At approximately what temperature would a heated material (metal, wood, etc.) begin to give off visible light at a deep red color?

Note: This will be the temperature where your spectrum first begins to come off of the wavelength axis in the visible region, and so is giving off a small amount of red light.

  • 500 K (440 Fahrenheit)
  • 1050 K (1430 Fahrenheit)
  • 1800 K (2780 Fahrenheit)
  • 2500 K (4040 Fahrenheit)

2. Click the – button that is to the left of the intensity scale to zoom out such that the top of the scale is at 10.

Move the temperature slider to that of a light bulb. The red part of the thermometer on the far right should just be touching the line marked light bulb. At approximately what temperature does the filament in a household light bulb operate?

Note: This is written in blue in the simulation.

  • 660 K (728 F)
  • 1800 K (2780 F)
  • 3000 K (4940 F)
  • 5700 K (9800 F)

3. What type of light does this light bulb produce most (i.e. at what wavelength does the spectrum have maximum intensity)?

  • Infrared light
  • Red visible light
  • Violet visible light
  • Ultraviolet light

4. Click the – button that is to the left of the intensity scale to zoom out such that the top of the scale is at 100.

Move the temperature slider to that of the Sun. The red part of the thermometer on the far right should just be touching the line marked Sun. Approximately what temperature is the surface of the Sun?

  • 2100 K (3320 F)
  • 4500 K (7640 F)
  • 5700 K (9800 F)
  • 9800 K (17,180 F

5. Based on the simulation, what type of light does the Sun produce the most?

  • Infrared light
  • Green visible light
  • Orange visible light
  • Ultraviolet light

6. Relative to the peak intensity in the Sun’s spectrum, the Sun emits nearly equal amounts of light across the entire visible part of the EM-spectrum. This is demonstrated by the star shaped symbol at the top of the simulation being white. Therefore, if you look at the Sun when it is directly overhead on a clear day, it will appear white.

Click the – button that is to the left of the intensity scale to zoom out such that the top of the scale is at 316.

Use the star shaped symbol above your graph and to the right of the blue, green, and red dots to estimate the temperature at which something will begin to glow blue. At approximately what temperature does the object gain a faint blue tint?

Note: This will also be the temperature where the max intensity of the objects spectrum is in the blue portion of the visible spectrum.

  • 3000 K (4940 F)
  • 6600 K (11,420 F)
  • 7900 K (13,760 F)
  • Object cannot glow blue at any temperature.

7.  Note that in the above question, although the object still emits all colors of visible light, it appears blue now instead of white because of the significant difference in the intensity or amount of blue light radiated versus the amount of red light emitted.

Click the + button that is to the left of the intensity scale to zoom in such that the top of the scale is at 1. Now slowly decrease the temperature from 5000K down to 300K (room temperature).

Notice how the entire spectrum decreases in intensity and moves to the right into the infrared region. Even though the spectrum appears completely flat, objects at room temperature and below also emit their own light. If our eyes could detect infrared light, we would be able to see in the dark with warmer objects being brighter than others.

In the introduction of this activity, we mentioned the temperature of your home on hot and cold days. Your body is kept warm in your home primarily by two ways: by direct contact with the air around you and by absorbing infrared light that is radiated from the walls. As you have seen in this activity, the light that is radiated from an object depends almost solely on the temperature of the object. Based on what you have learned here, what is one reason for feeling warmer in your house on a summer day versus a winter day even though your thermostat is set the same?

  • The walls of the house are warmer during the summer. Therefore, they radiate more infrared light that can serve to warm our body.
  • The walls of the house are warmer during the summer. Therefore, they radiate more visible light that can serve to warm our body.
  • The walls of the house are warmer during the summer. Therefore, they radiate more ultraviolet (UV) light that can serve to warm our body.
  • The temperature of the walls of the house has no effect on the light they radiate.

8. Since we cannot physically collect data from stars and most other objects in the universe, almost all of the information we obtain from the universe comes from analyzing the light, or spectra, from those objects.The study of light is known as spectroscopy.

As we have seen in this simulation, every blackbody emits light with an easily identified pattern known as the blackbody curve. This is the particular way the total light emitted by a blackbody varies with its frequency.  The exact form of the curve depends only on the body’s temperature. Since we can treat stars as blackbodies, this is incredibly useful in astronomy that shows us that the color of a star is also indicative of its temperature.

Use the simulation to determine the surface temperature of the following star:

Betelgeuse is a red supergiant star in the constellation Orion.

Knowing that Betelgeuse has peak intensity in the red and infrared wavelengths, adjust the intensity scale and temperature until you can determine the approximate surface temperature of the star.

  • 3500 K
  • 4800 K
  • 7700 K
  • 11,000 K

9. In this equation:

λ(max)= peak wavelength (cm)

T = temperature (K)

Based on what you have seen in the simulation and your knowledge of proportionality relationships learned this month, what is the relationship between temperature and peak wavelength?

  • They are directly proportional.
  • They are inversely proportional.
  • They are exponentially proportional.
  • They are unrelated

10.  Use Wien’s Law to calculate the peak wavelength of Betelgeuse, based on the temperature found in Question #8.

Note: 1 nanometer (nm) = .0000001 centimeters (cm)

  • 208 nm
  • 400 nm
  • 828 nm
  • 1800 nm
 
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Consequences Of The Fall And Contemporary Response

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In this assignment, you will identify the consequences of the fall of humanity that leads to human suffering, and describe how a Christian organization fights back for creational purpose.

One of the central components of every worldview is the topic of human nature. The topic of human nature asks questions about human value, human flourishing, and human purpose. Within the Christian worldview, the issue of sin and the consequences of the fall factor prominently into the topic of human nature.

In the “Consequences of the Fall and Contemporary Response” three-part document, you will explore the topic of human nature from the perspective of the Christian worldview. The first part of the assignment involves examining the immediate implications of the fall. The second and third parts of the assignment address how the effects of the fall are still evident in the world today.

For Part Two and Part Three, you will select an organization from the “Christian Organizations That Address a Consequence of the Fall” list provided in the topic study materials.

While GCU style is not required for the body of this assignment, solid academic writing is expected, and documentation of sources should be presented using APA documentation guidelines, which can be found in the GCU Style Guide, located in the Student Success Center.

This assignment uses a rubric. Please review the rubric prior to beginning the assignment to become familiar with the expectations for successful completion.

 
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