BSC1005 Biology General Chapter 10

Patterns of Inheritance

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Chapter 10: Patterns of Inheritance and Mendel Laws

Multiple-Choice Questions

2) Which of the following statements best represents the theory of pangenesis developed by Hippocrates? A) Pregnancy is a spontaneous event, and the characteristics of the offspring are determined by the gods. B) Particles called pangenes, which originate in each part of an organism’s body, collect in the sperm or eggs and are passed on to the next generation. C) Offspring inherit the traits of either the mother or the father, but not both. D) Fertilization of plants is dependent on an animal. E) Heritable traits are influenced by the environment and the behaviors of the parents. 3) Which of the following statements regarding hypotheses about inheritance is false? A) The theory of pangenesis incorrectly suggests that reproductive cells receive particles from somatic cells. B) Contrary to the theory of pangenesis, somatic cells do not influence eggs or sperm. C) The blending hypothesis does not explain how traits that disappear in one generation can reappear in later generations. D) The blending hypothesis suggests that all of the traits of the offspring come from either the mother or the father. E) Aristotle suggested that inheritance is the potential to produce body features. 4) Mendel conducted his most memorable experiments on A) peas. B) roses. C) guinea pigs. D) fruit flies. E) clones. 5) Varieties of plants in which self-fertilization produces offspring that are identical to the parents are referred to as A) hybrids. B) the F2 generation. C) monohybrid crosses. D) independent crosses. E) true-breeding. 6) Which of the following statements regarding cross-breeding and hybridization is false? A) The offspring of two different varieties are called hybrids. B) Hybridization is also called a cross. C) The parental plants of a cross are the P generation. D) The hybrid offspring of a cross are the P1 generation. E) The hybrid offspring of an F1 cross are the F2 generation. 7) A monohybrid cross is A) the second generation of a self-fertilized plant. B) a breeding experiment in which the parental varieties have only one trait in common. C) a breeding experiment in which the parental varieties differ in only one character. D) a triploid plant that results from breeding two very different plants. E) a breeding experiment in which the parental varieties have only one prominent trait. 8) Which of the following statements regarding genotypes and phenotypes is false? A) The genetic makeup of an organism constitutes its genotype. B) An organism with two different alleles for a single trait is said to be heterozygous for that trait. C) Alleles are alternate forms of a gene. D) An allele that is fully expressed is referred to as recessive. E) The expressed physical traits of an organism are called its phenotype.

BSC1005 Biology General Chapter 10

Patterns of Inheritance

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9) Research since Mendel’s time has established that the law of the segregation of genes during gamete formation A) applies to all forms of life. B) applies to all sexually reproducing organisms. C) applies to all asexually reproducing organisms. D) applies only to unicellular organisms. E) is invalid. 10) All the offspring of a cross between a black-eyed mendelien and an orange-eyed mendelien have black eyes. This means that the allele for black eyes is ________ the allele for orange eyes. A) codominant to B) recessive to C) more aggressive than D) dominant to E) better than 11) All the offspring of a cross between a black-eyed mendelien and an orange-eyed mendelien have black eyes. What is the expected phenotypic ratio of a cross between two orange-eyed mendeliens? A) 3 black-eyed:1 orange-eyed B) 0 black-eyed:1 orange-eyed C) 1 black-eyed:3 orange-eyed D) 1 black-eyed:0 orange-eyed E) 1 black-eyed:1 orange-eyed 12) The alleles of a gene are found at ________ chromosomes. A) the same locus on homologous mitochondrial B) the same locus on heterologous C) different loci on homologous D) different loci on heterologous E) the same locus on homologous 13) The phenotypic ratio resulting from a dihybrid cross showing independent assortment is expected to be A) 1:2:1. B) 3:1. C) 9:1:1:3. D) 3:9:9:1. E) 9:3:3:1. 14) If A is dominant to a and B is dominant to b, what is the expected phenotypic ratio of the cross: AaBb × AaBb? A) 16:0:0:0 B) 8:4:2:2 C) 4:4:4:4 D) 1:1:1:1 E) 9:3:3:1 15) Mendel’s law of independent assortment states that A) chromosomes sort independently of each other during mitosis and meiosis. B) genes sort independently of each other in animals but not in plants. C) independent sorting of genes produces polyploid plants under some circumstances. D) each pair of alleles segregates independently of the other pairs of alleles during gamete formation. E) genes are sorted concurrently during gamete formation. 16) Imagine that we mate two black Labrador dogs with normal vision and find that three of the puppies are like the parents, but one puppy is chocolate with normal vision and another is black with PRA (progressive retinal atrophy, a serious disease of vision).

BSC1005 Biology General Chapter 10

Patterns of Inheritance

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We can conclude that A) both of the parents are homozygous for both traits. B) one of the parents is homozygous for both traits. C) the same alleles that control coat color can also cause PRA. D) the alleles for color and vision segregate independently during gamete formation. E) the alleles for color and vision segregate dependently during gamete formation. 17) A testcross is A) a mating between an individual of unknown genotype and an individual homozygous recessive for the trait of interest. B) a mating between an individual of unknown genotype and an individual heterozygous for the trait of interest. C) a mating between an individual of unknown genotype and an individual homozygous dominant for the trait of interest. D) a mating between two individuals heterozygous for the trait of interest. E) a mating between two individuals of unknown genotype. 18) Using a six-sided die, what is the probability of rolling either a 5 or a 6? A) 1/6 × 1/6 = 1/36 B) 1/6 + 1/6 = 1/3 C) 1/6 + 1/6 = 2/3 D) 1/6 + 1/6 = 1/12 E) 1/6 19) Assuming that the probability of having a female child is 50% and the probability of having a male child is also 50%, what is the probability that a couple’s first-born child will be female and that their second-born child will be male? A) 20% B) 25% C) 50% D) 75% E) 100% 20) A carrier of a genetic disorder who does not show symptoms is most likely to be ________ to transmit it to offspring. A) heterozygous for the trait and able B) heterozygous for the trait and unable C) homozygous for the trait and able D) homozygous for the trait and unable E) heterozygous for the trait and unlikely 21) Dr. Smith’s parents have normal hearing. However, Dr. Smith has an inherited form of deafness. Deafness is a recessive trait that is associated with the abnormal allele d. The normal allele at this locus, associated with normal hearing, is D. Dr. Smith’s parents could have which of the following genotypes? A) DD and dd B) dd and dd C) Dd and Dd D) DD and DD E) Dd and DD 22) Most genetic disorders of humans are caused by A) multiple alleles. B) recessive alleles. C) drinking during pregnancy. D) a mutation that occurs in the egg, sperm, or zygote. E) dominant alleles.

BSC1005 Biology General Chapter 10

Patterns of Inheritance

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23) The vast majority of people afflicted with recessive disorders are born to parents who were A) both affected by the disease. B) not affected at all by the disease. C) slightly affected by the disease, showing some but not all of the symptoms. D) subjected to some environmental toxin that caused the disease in their children. E) affected by the disease but had subclinical symptoms. 24) Which of the following statements best explains why dominant alleles that cause lethal disorders are less common than recessive alleles that cause lethal disorders? A) Lethal disorders caused by dominant alleles are usually more severe than lethal disorders caused by recessive alleles. B) Unlike lethal disorders caused by recessive alleles, lethal disorders caused by dominant alleles usually cause the death of the embryo. C) Most individuals carrying a lethal dominant allele have the disorder and die before they reproduce, whereas individuals carrying a lethal recessive allele are more likely to be healthy and reproduce. D) The presence of a lethal dominant allele causes sterility. E) Many lethal recessive alleles cause enhanced disease resistance when they are present in the heterozygous state, and carriers of these alleles have more children, on average, than other people. 25) Amniocentesis and chorionic villus sampling allow for ________ and ________ of the fetus so that it can be tested for abnormalities. A) imaging . . . biochemical testing B) imaging . . . karyotyping C) sexing . . . imaging D) karyotyping . . . biochemical testing E) direct observation . . . biochemical testing 26) Which of the following statements regarding prenatal testing is false? A) Results from chorionic villus sampling come faster than from amniocentesis. B) Chorionic villus sampling is typically performed later in the pregnancy than amniocentesis. C) Ultrasound imaging has no known risk. D) The complication rate for chorionic villus sampling is about 2% and for amniocentesis is about 1%. E) Chorionic villus sampling and amniocentesis are usually reserved for pregnancies with higher than usual risks of complications. 27) Which of the following statements regarding genetic testing is false? A) Genetic testing before birth requires the collection of fetal cells. B) Carrier testing helps determine if a person carries a potentially harmful disorder. C) Most children with recessive disorders are born to healthy parents. D) The screening of newborns can catch inherited disorders right after birth. E) Most human genetic diseases are treatable if caught early. 28) For most sexually reproducing organisms, Mendel’s laws A) cannot strictly account for most patterns of inheritance. B) explain the reasons why certain genes are dominant. C) help us understand the global geographic patterns of genetic disease. D) indicate if a particular genotype will cause a certain phenotype. E) clarify the phenomenon of incomplete dominance. 29) Which of the following statements is false? A) Incomplete dominance supports the blending hypothesis. B) Heterozygotes for hypercholesterolemia have blood cholesterols about twice normal. C) The four blood types result from various combinations of the three different ABO alleles. D) ABO blood groups can provide evidence of paternity. E) The impact of a single gene on more than one character is called pleiotropy.

BSC1005 Biology General Chapter 10

Patterns of Inheritance

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30) All the offspring of a cross between a red-flowered plant and a white-flowered plant have pink flowers. This means that the allele for red flowers is ________ to the allele for white flowers. A) dominant B) codominant C) pleiotropic D) incompletely dominant E) recessive 31) Imagine that beak color in a finch species is controlled by a single gene. You mate a finch homozygous for orange (pigmented) beak with a finch homozygous for ivory (unpigmented) beak and get numerous offspring, all of which have a pale, ivory-orange beak. This pattern of color expression is most likely to be an example of A) incomplete dominance. B) codominance. C) pleiotropy. D) polygenic inheritance. E) crossing over. 32) Which of the following is an example of incomplete dominance in humans? A) sickle-cell disease B) hypercholesterolemia C) skin color D) ABO blood groups E) phenylketonuria 33) The expression of both alleles for a trait in a heterozygous individual illustrates A) incomplete dominance. B) codominance. C) pleiotropy. D) polygenic inheritance. E) blending inheritance. 34) A person with AB blood illustrates the principle of A) incomplete dominance. B) codominance. C) pleiotropy. D) polygenic inheritance. E) blending inheritance. 35) Which of the following statements regarding sickle-cell disease is false? A) Sickle-cell disease is common in tropical Africa. B) Persons who are heterozygous for sickle-cell disease are also resistant to malaria. C) Sickle-cell disease causes white blood cells to be sickle-shaped. D) All of the symptoms of sickle-cell disease result from the actions of just one allele. E) About one in ten African-Americans is a carrier of sickle-cell disease. 36) Sickle-cell disease is an example of A) codominance and pleiotropy. B) codominance and blended inheritance. C) multiple alleles, pleiotropy, and blended inheritance. D) codominance and multiple alleles. E) multiple alleles and pleiotropy.

BSC1005 Biology General Chapter 10

Patterns of Inheritance

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37) Which of the following terms refers to a situation where a single phenotypic character is determined by the additive effects of two or more genes? A) incomplete dominance B) codominance C) pleiotropy D) polygenic inheritance E) blending inheritance 38) Which of the following is essentially the opposite of pleiotropy? A) incomplete dominance B) codominance C) multiple alleles D) polygenic inheritance E) blending inheritance 39) The individual features of all organisms are the result of A) genetics. B) the environment. C) genetics and cytoplasmic determinants. D) the environment and individual needs. E) genetics and the environment. 40) The chromosome theory of inheritance states that A) chromosomes that exhibit mutations are the source of genetic variation. B) the behavior of chromosomes during meiosis and fertilization accounts for patterns of inheritance. C) the behavior of chromosomes during mitosis accounts for inheritance patterns. D) humans have 46 chromosomes. E) the inheritance pattern of humans is predetermined from chromosomes. 41) Genes located close together on the same chromosomes are referred to as ________ genes and generally ________. A) associated . . . sort independently during meiosis B) linked . . . sort independently during meiosis C) homologous . . . are inherited together D) linked . . . do not sort independently during meiosis E) codependent . . . do not sort independently during meiosis 42) Linked genes generally A) follow the laws of independent assortment. B) do not follow the laws of independent assortment. C) show incomplete dominance. D) reflect a pattern of codominance. E) show pleiotropy. 43) You conduct a dihybrid cross and then testcross the generation. A ________ ratio would make you suspect that the genes are linked. A) 3:1 B) 1:2:1 C) 1:1:1:1 D) 7:7:1:1 E) 9:3:3:1

BSC1005 Biology General Chapter 10

Patterns of Inheritance

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44) Crossing over ________ genes into assortments of ________ not found in the parents. A) recombines unlinked . . . genes B) recombines linked . . . alleles C) combines unlinked . . . alleles D) combines linked . . . genes E) recombines unlinked . . . chromosomes 45) The mechanism that “breaks” the linkage between linked genes is A) incomplete dominance. B) pleiotropy. C) codominance. D) independent assortment. E) crossing over. 46) Which of the following kinds of data could be used to map the relative position of three genes on a chromosome? A) the frequencies with which the genes exhibit incomplete dominance over each other B) the frequencies of mutations in the genes C) the frequencies with which the genes are inherited from the mother and from the father D) the frequencies with which the genes are heterozygous E) the frequencies with which the corresponding traits occur together in offspring 47) What is the normal complement of sex chromosomes in a human male? A) two X chromosomes B) two Y chromosomes C) two X chromosomes and one Y chromosome D) one X chromosome and one Y chromosome E) one Y chromosome 48) The sex chromosome complement of a normal human male is A) XO. B) XX. C) XY. D) YY. E) YO. 49) How many sex chromosomes are in a human gamete? A) one B) two C) three D) four E) five 50) How is sex determined in most ants and bees? A) by the X-Y system B) by the Z-W system C) by the number of chromosomes D) by the size of the sex chromosome E) by the X-O system

BSC1005 Biology General Chapter 11

Molecular Biology of the Gene

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Chapter 11: Molecular Biology of the Gene Multiple-Choice Questions 1) Which of the following statements regarding viruses is false? A) A virus is generally considered to be alive because it is cellular and can reproduce on its own. B) The host cell provides most of the tools and raw materials for viral multiplication. C) Once a person is infected with the herpes virus, the virus remains permanently latent in the body. D) Viruses can enter a host cell when the protein molecules on the outside of the virus fit into receptor molecules on the outside of the cell. E) Herpesviruses and the virus that causes AIDS can remain latent inside our cells for long periods of time. 2) Which of the following people conducted the experiments that demonstrated that DNA is the genetic material of bacteriophages? A) Watson and Crick B) Hershey and Chase C) Franklin D) Griffith E) Pauling 3) One type of virus that infects bacteria is called a A) phage. B) mage. C) rhinovirus. D) filovirus. E) coronavirus. 4) When a T2 bacteriophage infects an Escherichia coli cell, which part of the phage enters the bacterial cytoplasm? A) the whole phage B) only the RNA C) only the DNA D) the protein “headpiece” and its enclosed nucleic acid E) the tail fibers 5) The way that genetic material of a bacteriophage enters a bacterium is most like the way that A) a drug is injected with a hypodermic needle. B) a person swallows a pill. C) skin lotion is rubbed onto the hands. D) sugar dissolves in water. E) water soaks into a sponge. 6) The monomers of DNA and RNA are A) amino acids. B) monosaccharides. C) nucleotides. D) fatty acids. E) nucleic acids. 7) Which of the following statements regarding DNA is false? A) DNA uses the sugar deoxyribose. B) DNA uses the nitrogenous base uracil. C) DNA is a nucleic acid. D) One DNA molecule can include four different nucleotides in its structure. E) DNA molecules have a sugar-phosphate backbone.

BSC1005 Biology General Chapter 11

Molecular Biology of the Gene

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8) Which of the following statements regarding RNA is false? A) RNA uses the sugar dextrose. B) RNA uses the nitrogenous base uracil. C) RNA is a nucleic acid. D) One RNA molecule can include four different nucleotides in its structure. E) RNA molecules have a sugar-phosphate backbone. 9) Which of the following statements regarding the structure of DNA is false? A) The DNA molecule has a uniform diameter. B) In a DNA molecule, adenine bonds to thymine and guanine to cytosine. C) The DNA molecule is in the form of a double helix. D) Watson and Crick received a Nobel Prize for their description of the structure of DNA. E) The sequence of nucleotides along the length of a DNA strand is restricted by the base-pairing rules. 10) How would the shape of a DNA molecule change if adenine paired with guanine and cytosine paired with thymine? A) The DNA molecule would be longer. B) The DNA molecule would be shorter. C) The DNA molecule would be circular. D) The DNA molecule would have regions where no base-pairing would occur. E) The DNA molecule would have irregular widths along its length. 11) The shape of a DNA molecule is most like A) a set of railroad tracks. B) a diamond ring. C) a twisted rope ladder. D) a gold necklace. E) the letter X. 12) Which of the following statements regarding a DNA double helix is always true? A) The amount of adenine is equal to the amount of uracil, and the amount of guanine is equal to the amount of cytosine. B) The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of uracil. C) The amount of adenine is equal to the amount of guanine, and the amount of thymine is equal to the amount of cytosine. D) The amount of adenine is equal to the amount of cytosine, and the amount of guanine is equal to the amount of thymine. E) The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine. 13) DNA replication A) occurs through the addition of nucleotides to the end of the DNA molecule. B) results in the formation of four new DNA strands. C) produces two daughter DNA molecules that are complementary to each other. D) uses each strand of a DNA molecule as a template for the creation of a new strand. E) begins when two DNA molecules join together to exchange segments. 14) If one strand of DNA is CGGTAC, the corresponding strand would be A) GCCTAG. B) CGGTAC. C) GCCAUC. D) TAACGT. E) GCCATG.

BSC1005 Biology General Chapter 11

Molecular Biology of the Gene

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15) The copying mechanism of DNA is most like A) using a photographic negative to make a positive image. B) mixing flour, sugar, and water to make bread dough. C) joining together links to make a chain. D) carving a figure out of wood. E) threading beads onto a string. 16) When one DNA molecule is copied to make two DNA molecules, the new DNA contains A) none of the parent DNA. B) 25% of the parent DNA. C) 50% of the parent DNA. D) 75% of the parent DNA. E) 100% of the parent DNA 17) Multiple origins of replication on the DNA molecules of eukaryotic cells serve to A) remove errors in DNA replication. B) create multiple copies of the DNA molecule at the same time. C) shorten the time necessary for DNA replication. D) reduce the number of “bubbles” that occur in the DNA molecule during replication. E) assure the correct orientation of the two strands in the newly growing double helix. 18) Which of the following enzymes catalyzes the elongation of a new DNA strand? A) helicase B) primase C) ligase D) single-stranded binding protein E) DNA polymerase 19) Why does a DNA strand grow only in the 5′ to 3′ direction? A) because DNA polymerases can only add nucleotides to the 3′ end of the growing molecule B) because DNA polymerases can only add nucleotides to the 5′ end of the growing molecule C) because mRNA can only read a DNA molecule in the 5′ to 3′ direction D) because the DNA molecule only unwinds in the 5′ to 3′ direction E) because DNA polymerase requires the addition of a starter nucleotide at the 5′ end 20) Which of the following options best depicts the flow of information when a gene directs the synthesis of a cellular component? A) RNA → DNA → RNA → protein B) DNA → RNA → protein C) protein → RNA → DNA D) DNA → amino acid → RNA → protein E) DNA → tRNA → mRNA → protein 21) The transfer of genetic information from DNA to RNA is called A) translation. B) transcription. C) initiation. D) elongation. E) promotion. 22) The “one gene-one polypeptide” theory states that A) the synthesis of each gene is catalyzed by one specific enzyme. B) the synthesis of each enzyme is catalyzed by one specific gene. C) the function of an individual gene is to dictate the production of a specific polypeptide. D) each polypeptide catalyzes a specific reaction.

BSC1005 Biology General Chapter 11

Molecular Biology of the Gene

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E) the function of each polypeptide is to regulate the synthesis of each corresponding gene. 23) Experiments have demonstrated that the “words” of the genetic code (the units that specify amino acids) are A) single nucleotides. B) two-nucleotide sequences. C) three-nucleotide sequences. D) nucleotide sequences of various lengths. E) enzymes. 24) The directions for each amino acid in a polypeptide are indicated by a codon that consists of ________ nucleotide(s) in an RNA molecule. A) 5 B) 4 C) 3 D) 2 E) 1 25) We would expect that a 15-nucleotide sequence will direct the production of a polypeptide that consists of A) 2 amino acids. B) 3 amino acids. C) 4 amino acids. D) 5 amino acids. E) 6 amino acids. 26) A base substitution mutation in a gene does not always result in a different protein. Which of the following factors could account for this? A) the fact that the mutation affects only the sequence of the protein’s amino acids, so the protein stays the same B) the double-ring structure of adenine and guanine C) a correcting mechanism that is part of the mRNA molecule D) the fact that such mutations are usually accompanied by a complementary deletion E) the fact that some amino acids are specified from more than one codon 27) Which of the following enzymes catalyzes the linking together of RNA nucleotides to form RNA? A) RNA polymerase B) RNA ligase C) a ribozyme D) reverse transcriptase E) tRNA 28) Which of the following occurs when RNA polymerase attaches to the promoter DNA? A) elongation of the growing RNA molecule B) termination of the RNA molecule C) addition of nucleotides to the DNA template D) initiation of a new RNA molecule E) initiation of a new polypeptide chain 29) ________ marks the end of a gene and causes transcription to stop. A) RNA polymerase B) RNA ligase C) A terminator D) Reverse transcriptase E) Methionine

BSC1005 Biology General Chapter 11

Molecular Biology of the Gene

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30) Where do transcription and translation occur in prokaryotic cells? A) on the plasma membrane B) in the nucleus C) in the cytoplasm D) in chromatophores E) in the cell wall 31) Which of the following statements about eukaryotic RNA is true? A) Introns are added to the RNA. B) Exons are spliced together. C) A small cap of extra nucleotides is added to both ends of the RNA. D) A long tail of extra nucleotides is removed from the 5′ end of the RNA. E) The modified RNA molecule is transported into the nucleus. 32) Which of the following takes place during translation? A) the conversion of genetic information from the language of nucleic acids to the language of proteins B) the conversion of genetic information from DNA nucleotides into RNA nucleotides C) the addition of nucleotides to a DNA template D) the conversion of genetic information from the language of proteins to the language of enzymes E) DNA replication 33) Which of the following is a function of tRNA? A) joining to several types of amino acid B) recognizing the appropriate anticodons in mRNA C) transferring nucleotides to rRNA D) helping to translate codons into nucleic acids E) joining to only one specific type of amino acid 34) Which of the following is not needed in order for translation to occur? A) DNA template B) ribosomes C) tRNA D) various enzymes and protein “factors” E) sources of energy, including ATP 35) Which of the following statements about ribosomes is false? A) A ribosome consists of two subunits. B) Subunits of RNA are made of proteins and ribosomal RNA. C) The ribosomes of prokaryotes and eukaryotes are the same in structure and function. D) Each ribosome has two binding sites for tRNA. E) Ribosomes coordinate the functioning of mRNA and tRNA. 36) Which of the following statements is false? A) Translation consists of initiation, elongation, and termination. B) During polypeptide initiation, an mRNA, the first amino acid attached to its tRNA, and the two subunits of a ribosome are brought together. C) An mRNA molecule transcribed from DNA is shorter than the genetic message it carries. D) During the first step of initiation, an mRNA molecule binds to a small ribosomal subunit. E) During the second step of initiation, a large ribosomal subunit binds to a small ribosomal subunit. 37) Which of the following options most accurately lists the sequence of events in translation? A) codon recognition → translocation → peptide bond formation → termination B) peptide bond formation → codon recognition → translocation → termination C) codon recognition → peptide bond formation → translocation → termination

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Molecular Biology of the Gene

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D) codon recognition → peptide bond formation → termination → translocation E) peptide bond formation → translocation → codon recognition → termination 38) Which of the following statements regarding the flow of genetic information is false? A) Polypeptides form proteins that determine the appearance and function of the cell and organism. B) Eukaryotic mRNA is processed in several ways before export out of the nucleus. C) The codons in a gene specify the amino acid sequence of a polypeptide. D) Transcription occurs in the cytoplasm of eukaryotic cells. E) Ribosomes function as factories that coordinate the functioning of mRNA and tRNA. 39) Any change in the nucleotide sequence of DNA is called A) a mutation. B) an advantage. C) a codon. D) a translation. E) an anticodon. 40) Consider the following sentence: “The dog did not eat.” Which of the following variations of this sentence is most like a base substitution mutation? A) The dog did not et. B) The dog dog did not eat. C) The did dog not eat. D) The doe did not eat. E) The dog did not. 41) Consider the following sentence: “The dog did not eat.” Which of the following variations of this sentence is most like a reading frame mutation? A) The dog dog did not eat. B) The did dog not eat. C) The dod idn ote at. D) The did not eat. E) The dog did dog did not eat. 42) A physical or chemical agent that changes the nucleotide sequence of DNA is called a(n) A) reverse transcriptase. B) terminator. C) transposon. D) mutagen. E) anticodon. 43) A protein shell enclosing a viral genome is known as a(n) A) capsule. B) envelope. C) phage. D) capsid. E) prophage. 44) Which of the following features characterizes the lytic cycle of a viral infection? A) The cycle typically ends when the host bacterium divides. B) The cycle typically leads to the lysis of the host cell. C) The viral DNA is inserted into a bacterial chromosome. D) The virus reproduces outside of the host cell. E) The viral genes typically remain inactive once they are inside the host cell.

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45) Which of the following statements is false? A) Some prophage genes can cause the transformation of a nonpathogenic bacterium into a form that causes human disease. B) Sometimes an environmental signal can trigger a switchover from the lysogenic to the lytic cycle. C) The lysogenic cycle always occurs inside of host cells. D) The lysogenic cycle typically results in the rapid lysis of all infected cells. E) During a lysogenic cycle, viral DNA replication typically occurs without destroying the host cell. 46) Viral DNA incorporated into host cell DNA is known as a(n) A) capsid. B) prophage. C) envelope. D) phage. E) genome. 47) The envelope of a flu virus A) helps the virus enter the cell. B) is coded by viral genes. C) helps the virus insert its DNA into the host cell genome. D) changes rapidly, thereby helping the virus evade an immune system response. E) accounts for viral resistance to antibiotics. 48) Which of the following statements about herpesviruses is false? A) Herpesviruses reproduce inside the host cell’s mitochondria. B) Herpesviruses acquire their envelopes from the host cell nuclear membrane. C) Herpesviruses are DNA viruses. D) Herpesviruses may remain latent for long periods of time while inside the host cell nucleus. E) Herpesviruses may cause cold sores or genital sores to appear during times of physical or emotional stress. 49) Which of the following statements about plant viruses is false? A) Once in a plant, a virus can spread from cell to cell through plasmodesmata. B) The genetic material in most plant viruses is RNA. C) Preventing infections and breeding resistant plants can control viral infection in plants. D) To infect a plant, a virus must first get past the plant’s epidermis. E) There are many successful ways to rid infected plants of a virus. 50) Which of the following statements regarding viral diseases is false? A) RNA viruses tend to have an unusually high rate of mutation because their RNA genomes cannot be corrected by proofreading. B) New viral diseases often emerge when a virus infects a new host species. C) Very few new human diseases have originated in other animals because the genetic differences are too great. D) Some new viral diseases arise as a result of a mutation of existing viruses. E) AIDS was around for decades before becoming a widespread epidemic. 51) What will be the most likely cause of a new avian flu pandemic like the 1918-1919 flu pandemic that killed approximately 40 million people worldwide? A) sexual promiscuity B) intravenous drug use and abuse C) easy viral transmission from person to person D) blood transfusions with tainted blood E) increased international travel at affordable rates

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52) What kind of virus is HIV? A) a herpesvirus B) a paramyxovirus C) a retrovirus D) a complex virus E) a provirus 53) Which of the following enzymes does HIV use to synthesize DNA on an RNA template? A) ligase B) RNA polymerase C) terminator enzyme D) reverse transcriptase E) DNA convertase 54) HIV does the greatest damage to A) the adrenal glands. B) pancreatic cells. C) nervous tissue. D) gametes. E) white blood cells. 55) How do viroids harm the plants that are infected with them? A) by increasing the plants’ metabolic rate B) by altering the plants’ growth C) by reducing the plants’ seed production D) by preventing leaf production E) by destroying the root system 56) Which of the following statements about the treatment or prevention for a prion infection is true? A) Antibiotic therapies such as penicillin are very effective cures. B) High doses of anti-inflammatory drugs such as ibuprofen reduce the symptoms of prion infections. C) Corticosteroid therapy is the only drug therapy that can reverse the effects of a prion infection. D) Preventative vaccines have recently been shown to be effective in preventing prion infections. E) There is no known treatment or cure for prion infections. 57) In the 1920s, Frederick Griffith conducted an experiment in which he mixed the dead cells of a bacterial strain that can cause pneumonia with live cells of a bacterial strain that cannot. When he cultured the live cells, some of the daughter colonies proved able to cause pneumonia. Which of the following processes of bacterial DNA transfer does this experiment demonstrate? A) transduction B) conjugation C) transformation D) transposition E) crossing over 58) Transduction A) is the direct transfer of DNA from one bacterium to another. B) occurs when a bacterium acquires DNA from the surrounding environment. C) is the result of crossing over. D) occurs when a phage transfers bacterial DNA from one bacterium to another. E) requires DNA polymerase. 59) Conjugation A) is the direct transfer of DNA from one bacterium to another. B) occurs when a bacterium acquires DNA from the surrounding environment.

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C) is the result of crossing over. D) occurs when a phage transfers bacterial DNA from one bacterium to another. E) requires DNA polymerase. 60) Conjugation, transformation, and transduction are all ways that bacteria A) reduce their DNA content. B) increase the amount of RNA in the cytoplasm. C) change their ribosomes to eukaryotic ribosomes. D) increase their genetic diversity. E) alter their oxygen requirements. 61) A friend accidentally sends an email to you that contains a computer virus from his computer. Without knowing it, you infect your computer with the virus when you open the email. This process of spreading the computer virus using emails is most like which of the following processes? A) binary fission B) conjugation C) transduction D) transformation E) mitosis 62) When a bacterial cell with a chromosome-borne F factor conjugates with another bacterium, how is the transmitted donor DNA incorporated into the recipient’s genome? A) It is substituted for the equivalent portion of the recipient’s chromosome by the process of crossing over. B) It circularizes and becomes one of the recipient cell’s plasmids. C) The genes on the donor DNA of which the recipient does not have a copy are added to the recipient chromosome; the remainder of the donor DNA is degraded. D) The DNA of the recipient cell replicates, and the donor DNA is added to the end of the recipient DNA. E) The donor and recipient DNA are both chopped into segments by restriction enzymes, and a new, composite chromosome is assembled from the fragments 63) In many bacteria, genes that confer resistance to antibiotics are carried on A) factors. B) R plasmids. C) dissimilation plasmids. D) transposons. E) exons. 64) Conjugation between a bacterium that lacks an F factor (F-) and a bacterium that has an F factor on its chromosome (F+) would typically produce which of the following results? A) The F- bacterium ends up carrying one or more plasmids from the F+ bacterium; the F+ bacterium is unchanged. B) The F+ bacterium ends up with a recombinant chromosome that carries some genes from the F- bacterium, and the F- bacterium ends up with an unaltered chromosome. C) The F+ bacterium ends up with a recombinant chromosome that carries some genes from the F- bacterium, and the F- bacterium ends up with a chromosome that lacks those genes. D) The F- bacterium ends up with a recombinant chromosome that carries some genes from the F+ bacterium, and the F+ bacterium ends up with an unaltered chromosome. E) The F- bacterium ends up with a recombinant chromosome that carries some genes from the F+ bacterium, and the F+ bacterium ends up with a chromosome that lacks those genes. 65) A functional F factor that is an R plasmid must contain all of the following elements except A) genes for making sex pili. B) genes for making the enzymes needed for conjugation. C) a site for making the proteins needed for conjugation.

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D) a site where DNA replication can begin. E) genes for enzymes that confer resistance to antibiotics. 66) Which of the following human activities has contributed to an increase in the number of bacteria having R plasmids? A) nitrogen fixation by genetically engineered plants B) widespread use of childhood vaccination in developing countries C) improper use of restriction enzymes in research and medical facilities D) increased carcinogen exposure from excessive fossil fuel burning E) heavy use of antibiotics in medicine and in agriculture

BSC1005 Biology General Chapter 12

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Chapter 12: How Genes Are Controlled

Multiple-Choice Questions

1) Which of the following statements about the problems created by cloning is false? A) Cloned animals are less healthy than animals created by natural methods. B) Cloning does not increase genetic diversity in the cloned species. C) Cloning endangered species may de-emphasize the need to preserve critical natural habitats. D) Cloned animals live longer compared to naturally bred animals. E) Cloning leads to malfunctions in gene regulation. 2) The fact that the nucleus from an adult somatic cell can be used to create all of the cell types in a new organism demonstrates that development depends upon A) the control of gene expression. B) the timing of mitosis and meiosis. C) the timing of meiosis and cell migrations. D) the deposition of materials in the extracellular matrix. E) the position of cells within an embryo. 3) The term “gene expression” refers to the A) fact that each individual of a species has a unique set of genes. B) fact that individuals of the same species have different phenotypes. C) process by which genetic information flows from genes to proteins. D) fact that certain genes are visible as dark stripes on a chromosome. E) flow of information from parent to offspring. 4) A gene operon consists of A) a transcribed gene only. B) a promoter only. C) a regulatory gene only. D) transcribed genes, an operator, and a promoter. E) transcribed genes, a promoter, and a regulatory gene. 5) In a prokaryote, a group of genes with related functions, along with their associated control sequences, defines A) an allele. B) an operon. C) a locus. D) a transposon. E) a chromosome. 6) The lac operon in E. coli A) prevents lactose-utilizing enzymes from being expressed when lactose is absent from the environment. B) coordinates the production of tryptophan-utilizing enzymes when it is present. C) allows the bacterium to resist antibiotics in the penicillin family. D) regulates the rate of binary fission. E) uses activators to initiate the production of enzymes that break down lactose. 7) Proteins that bind to DNA and turn on operons by making it easier for RNA polymerase to bind to a promoter are called A) regulators. B) inhibitors. C) operators. D) activators. E) repressors.

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8) The lac operon of E. coli is ________ when the repressor is bound to lactose. A) active B) inactive C) elongated D) cloned E) unregulated 9) The expression of the tryptophan operon is controlled by A) a repressor that is active when it is alone. B) a repressor that is inactive when it binds to lactose. C) a repressor that is active when it binds to tryptophan. D) an activator that turns the operon on by binding to DNA. E) an activator that permanently deletes genes in the tryptophan operon. 10) Which of the following is likely to occur in E. coli cells that are grown in skim milk? A) The lac operon is shut off and the cells will not produce lactose-utilizing enzymes. B) The trp repressor is activated and the cells will produce lactose-utilizing enzymes. C) The trp operon is turned on but the bacteria will not produce lactose-utilizing enzymes. D) The trp operon and the lac operon are both switched off. E) The trp operon and the lac operon are both switched on. 11) A single cell, the zygote, can develop into an entirely new organism with many different specialized cells. Which of the following statements about this process is false? A) Additional genetic information for the formation of specialized cells is passed on to the developing embryo via the placenta. B) The descendant cells specialize by a process known as cellular differentiation. C) The zygote contains all of the genetic information required for the development of many different cell types. D) Only some of the genes in the zygote are expressed in all of its descendant cells. E) Differentiation of the zygote into a multicellular organism results from selective gene expression. 12) The genes for the enzymes of glycolysis A) are active in all metabolizing cells, but the genes for specialized proteins are expressed only in particular cell types. B) are inactive in all metabolizing cells, but the genes for specialized proteins are expressed in all cell types. C) and the genes for all specialized proteins are expressed in all metabolizing cells. D) and the genes for specialized proteins are expressed in all nonembryonic cell types. E) and the genes for all specialized proteins are expressed in all embryonic cells. 13) Which of the following statements regarding DNA packing is false? A) A nucleosome consists of DNA wound around a protein core of eight histone molecules. B) DNA packing tends to promote gene expression. C) Histones account for about half the mass of eukaryotic chromosomes. D) Highly compacted chromatin is generally not expressed at all. E) Prokaryotes have proteins analogous to histones. 14) The relationship between DNA and chromosomes is most like A) an egg yolk inside of an egg. B) a dozen eggs packaged within an egg carton. C) a spoon cradling some peas. D) thread wrapped around a spool. E) the candy shell surrounding the chocolate in a piece of M & M candy. 15) In female mammals, the inactive X chromosome in each cell A) becomes a nucleotroph corpus. B) can be activated if mutations occur in the active X chromosome.

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C) is broken down, and its nucleotides are degraded and reused. D) is absorbed and used in energy production. E) becomes a Barr body. 16) The tortoiseshell pattern on a cat A) usually occurs in males. B) is the result of a homozygous recessive condition. C) results from X chromosome inactivation. D) is a result of alleles on the Y chromosome. E) occurs in male cats 25% of the time and in female cats 50% of the time. 17) Both prokaryotic and eukaryotic cells use ________ to turn certain genes on or off. A) DNA ligase B) RNA transcriptase C) intron segments D) regulatory proteins E) nucleosome packing 18) Enhancers are A) adjacent to the gene that they regulate. B) required to turn on gene expression when transcription factors are in short supply. C) the site on DNA to which activators bind. D) required to facilitate the binding of DNA polymerases. E) the products of transcription factors. 19) Silencers are sites in DNA that A) bind RNA promoters to promote the start of transcription. B) bind enhancers to promote the start of transcription. C) bind repressor proteins to inhibit the start of transcription. D) bind activators to inhibit the start of transcription. E) release mRNA. 20) RNA splicing involves the A) addition of a nucleotide “cap” to the molecule. B) addition of a nucleotide “tail” to the molecule. C) removal of introns from the molecule. D) removal of exons from the molecule. E) addition of introns to the molecule. 21) The coding regions of a gene (the portions that are expressed as polypeptide sequences) are called A) introns. B) exons. C) redundant coding sections. D) proto-oncogenes. E) nucleosomes. 22) Which of the following permits a single gene to code for more than one polypeptide? A) retention of different introns in the final version of the different mRNA strands B) alternative RNA splicing C) protein degradation D) genetic differentiation E) addition of different types of caps and tails to the final version of the mRNA strands

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23) Small pieces of RNA that can regulate mRNA transcription are called A) microRNA. B) minuteRNA. C) miniRNA. D) monoRNA. E) minorRNA. 24) miRNA can be used by A) researchers to induce the production of more mRNA. B) researchers to stimulate the production of DNA. C) researchers to artificially turn on gene expression. D) viruses to stop the production of new proteins. E) cells to prevent infections from double-stranded RNA viruses. 25) Which of the following statements regarding RNA and proteins is false? A) Some genes are edited before they are translated. B) Some polypeptides are edited to make them functional. C) The length of time that mRNA remains functional in the cytoplasm is quite variable. D) In eukaryotes, the lifetime of a protein is closely regulated. E) In eukaryotes, one gene controls the production of just one functioning protein. 26) All of the following mechanisms are used to regulate protein production except A) controlling the start of polypeptide synthesis. B) protein activation. C) protein breakdown. D) DNA editing. E) the breakdown of mRNA. 27) The textbook authors’ analogy between the regulation of gene expression and the movement of water through pipes includes all of the following except A) the web of control that connects different genes. B) pretranscriptional events. C) post-transcriptional events. D) the editing of RNA. E) the multiple mechanisms by which gene expression is regulated. 28) Which of the following mechanisms of controlling gene expression occurs outside of the nucleus? A) adding a cap and tail to RNA B) transcription C) DNA packing/unpacking D) RNA splicing E) translation 29) Which of the following statements about fruit fly development is false? A) One of the earliest development events is the determination of the head and tail ends of the egg. B) The location of the head and tail ends of the egg is primarily determined by the location of sperm entry during fertilization. C) Cell signaling plays an important role in the development of fruit flies. D) Homeotic genes regulate batteries of other genes that direct the anatomical identity of body parts. E) Cascades of gene expression routinely direct fruit fly development. 30) A homeotic gene A) turns on the genes necessary for synthesis of proteins. B) serves as a master control gene that functions during embryonic development by controlling the developmental fate of groups of cells.

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C) represses gene transcription and promotes mRNA translation. D) produces a product that controls the transcription of other genes. E) is found only in adult somatic cells. 31) Which of the following statements about microarrays is false? A) Microarrays enable scientists to determine the activity of thousands of genes at once. B) Microarrays use tiny portions of double-stranded RNA fragments from a large number of genes. C) Microarrays are used to determine which genes are active in different tissues or in tissues of different states of health. D) Microarrays use fluorescently labeled cDNA molecules to identify particular genes expressed at a particular time. E) Microarrays help scientists understand how genes interact, particularly during embryonic development. 32) Animal development is directed by A) cell receptors that detect transcription factors. B) the availability of certain “key” nutrients as cells divide. C) signal transduction pathways. D) cell-to-cell signaling. E) cell-to-cell signaling and signal transduction pathways. 33) To initiate a signal transduction pathway, a signal binds to a receptor protein usually located in the A) cytosol. B) nucleus. C) plasma membrane. D) ER. E) cytoplasm. 34) Transcription factors attach to A) DNA. B) signal molecules. C) plasma membrane receptors. D) proteins. E) mRNA. 35) A signal outside a cell triggers changes in the transcription and translation inside the cell through the process of A) post-translational editing. B) signal transduction pathways. C) protein activation. D) protein breakdown. E) X chromosome inactivation. 36) The basis of cellular differentiation is A) the operon. B) cellular specialization. C) selective gene expression. D) cloning. E) mutation. 37) Yeast are able to communicate with each other A) by close cell-to-cell contact. B) with signal transduction pathways. C) only if they can touch each other and have merged cell walls. D) with pseudopodia. E) only when a yeast cell has died and released its internal organelles into the external environment.

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38) Signal transduction pathways A) are found strictly in multicellular organisms for cell-to-cell communication. B) first appeared in animals when primates began to walk upright. C) are limited for use in sexual identification. D) originally evolved in vertebrates. E) are mechanisms of communication that evolved in the ancient prokaryotes. 39) Most differentiated cells retain A) only a tiny fraction of their original set of genes. B) only a tiny fraction of their original set of genes, but can regenerate lost genes as needed. C) a complete set of their genes, but lose the ability to express most of those genes. D) a complete set of their genes, and retain the ability to express those genes under certain circumstances. E) the ability to dedifferentiate, but then cannot return to their original differentiated state. 40) Why can some plants be cloned from a single cell? A) Plant cells do not differentiate even when mature, so any cell can grow into an entire plant. B) Plant cells can dedifferentiate and give rise to all of the specialized cells required to produce an entire plant. C) Plant cells are able to retrieve genes lost to the environment during development. D) Plant cells can produce genes to replace those lost during development. E) Plant cells are capable of self-renewal by utilizing cellular components from adjacent cells . 41) Which of the following processes occurs when a salamander regenerates a lost limb? A) Oncogenes that cause accelerated cell division are turned on. B) Certain cells in the limb dedifferentiate, divide, and then redifferentiate to form a new limb. C) A new salamander develops from the lost limb. D) The homeotic genes of the regenerating cells turn off. E) The cell cycle is arrested and apoptosis begins. 42) The cloning of Dolly the sheep A) demonstrated that the nuclei from differentiated mammalian cells can retain their full genetic potential. B) demonstrated that differentiated cells contain only a fraction of their full genetic potential. C) demonstrated, for the first time, that eggs are haploid and body cells are diploid. D) revealed that cloned mammals most resemble the egg donor. E) revealed that cloned mammals most resemble the sperm donor. 43) Cloning to produce embryonic stem cells is called A) regenerative cloning. B) transplantational cloning. C) reproductive cloning. D) therapeutic cloning. E) dedifferentiation. 44) Which of the following mammals has not yet been cloned and brought through the complete gestation cycle? A) cow B) human C) pig D) dog E) cat 45) Which of the following possible uses of reproductive cloning is still considered by most to be an unresolved ethical issue? A) the production of genetically identical animals for experimentation B) the production of potentially valuable drugs C) the production of organs in pigs for transplant into humans D) the improvement of the quality of farm animals E) the production of genetically identical humans for therapeutic purposes.

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46) Which of the following statements regarding stem cells is false? A) Embryonic stem cells can be induced to differentiate. B) Embryonic stem cells can give rise to all the different specialized cells in the body. C) Adult, but not embryonic, stem cells can be grown in laboratory culture. D) Adult stem cells are present in adult tissues. E) Adult stem cells are partway along the road to differentiation. 47) Adult stem cells have limited therapeutic potential A) because they are fully differentiated. B) because they lack a complete set of genes. C) due to their excessive numbers in tissues. D) because scientists have no reliable method of identification. E) because their developmental potential is limited to certain tissues. 48) A gene that can cause cancer when present in a single copy in a cell is called a(n) A) oncogene. B) enhancer gene. C) silencer gene. D) carcinogen. E) proto-oncogene. 49) Which of the following statements about proto-oncogenes is false? A) Proto-oncogenes are normal genes with the potential to become oncogenes. B) Many proto-oncogenes code for growth factors. C) A mutation must occur in a cell’s DNA for a proto-oncogene to become an oncogene. D) A mutation in a tumor-suppressor gene can stop cell division immediately. E) One of the earliest clues to understanding cancer was the discovery of a virus that causes cancer in chickens. 50) Which of the following is not a factor that contributes to normal cells becoming cancerous? A) the conversion of a proto-oncogene to an oncogene B) damage to a tumor-suppressor gene C) the acquisition of an oncogene from a virus D) one or more of the cell’s genes being removed by a virus E) excessive replication of proto-oncogenes 51) Cancer of the colon is caused by A) a single gene mutation. B) several somatic cell mutations. C) exposure of colon cells to a mutagen. D) lack of vitamin K. E) the proto-oncogene, lac. 52) The development of colon cancer occurs slowly and is more prominent in the elderly than the young. This is most likely because A) cancer cells don’t have mitochondria, so they grow slowly. B) four or more somatic mutations must occur to give rise to the cancer, which takes time. C) cancer cells suppress the growth of each other in a tissue. D) cancer cells have to wait until new blood vessels grow into the area, which takes much time. E) most cancer mutations interfere with mitosis, so cell division occurs more slowly. 53) Mutations in the proto-oncogenes ras and p53 A) increase protein synthesis by the cell. B) are rarely associated with cancers. C) can improve the chance of avoiding cancer as one ages. D) can enhance further mutations, which can develop into cancer.

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E) disrupt normal regulation of the cell cycle. 54) Mutations in the p53 gene can lead to cancer by A) causing the production of excessive amounts of relay proteins. B) turning off a gene for a protein that inhibits cell division. C) increasing the production of glycogen, which nourishes the cell cycle. D) promoting the expression of mRNA that can interact with DNA, resulting in new mutations. E) increasing the production of growth hormones, which trigger faster cell cycles. 55) The carcinogen known to cause the most cases of cancer is A) plutonium. B) ultraviolet light. C) alcohol. D) salt. E) tobacco. 56) Which of the following statements regarding cancer risk factors is false? A) Factors that alter DNA and make cells cancerous are called carcinogens. B) Mutagens are usually not carcinogens. C) X-rays and ultraviolet radiation are two of the most potent carcinogens. D) Eating 20-30 grams of plant fiber daily and reducing the intake of animal fat can reduce your risk of developing colon cancer. E) Broccoli and cauliflower are thought to be especially rich in substances that help prevent cancer.