Second Semester Exam - Biology

29) The recessive allele of a gene causes cystic fibrosis. For this gene among Caucasians, p = 0.98. If a Caucasian population is in Hardy-Weinberg equilibrium with respect to this gene, what proportion of babies is born homozygous recessive, and therefore suffers cystic fibrosis? A) 0.022 = 0.0004 B) 0.02 C) 0.982 = 0.9604 D) 2(0.02 × 0.98) = 0.0392 E) 0.98

A) 0.022 = 0.0004

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

A) DNA template

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.

A) Herpesviruses reproduce inside the host cell's mitochondria.

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.

A) It is substituted for the equivalent portion of the recipient's chromosome by the process of crossing over.

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

A) RNA polymerase

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.

A) RNA uses the sugar dextrose.

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.

A) a drug is injected with a hypodermic needle.

44) Which of the following would most quickly be eliminated by natural selection? A) a harmful allele in an asexual, haploid population B) a harmful recessive allele in a sexual, diploid population C) a harmful recessive allele in a sexual, polyploid population D) any harmful allele, regardless of the system of inheritance in a population E) neutral variation, because it is not needed

A) a harmful allele in an asexual, haploid population

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.

A) a mutation.

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

A) because DNA polymerases can only add nucleotides to the 3' end of the growing molecule

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.

A) cannot strictly account for most patterns of inheritance.

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.

A) codominance and pleiotropy.

33) Thirty people are selected for a long-term mission to colonize a planet many light years away from Earth. The mission is successful and the population rapidly grows to several hundred individuals. However, certain genetic diseases are unusually common in this group, and their gene pool is quite different from that of the Earth population they have left behind. Which of the following phenomena has left its mark on this population? A) founder effect B) bottleneck effect C) gene flow D) high rates of mutation E) natural selection

A) founder effect

34) Genetic differences between populations tend to be reduced by A) gene flow. B) mutation. C) the founder effect. D) the bottleneck effect. E) natural selection.

A) gene flow.

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.

A) helps the virus enter the cell.

41) Mate-attracting features such as the bright plumage of a male peacock result from A) intersexual selection. B) intrasexual selection. C) disruptive selection. D) directional selection. E) stabilizing selection.

A) intersexual selection.

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. C) is the result of crossing over. D) occurs when a phage transfers bacterial DNA from one bacterium to another. E) requires DNA polymerase.

A) is the direct transfer of DNA from one bacterium to another.

49) How many sex chromosomes are in a human gamete? A) one B) two C) three D) four E) five

A) one

3) One type of virus that infects bacteria is called a A) phage. B) mage. C) rhinovirus. D) filovirus. E) coronavirus.

A) phage.

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

A) the conversion of genetic information from the language of nucleic acids to the language of proteins

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.

A) using a photographic negative to make a positive image.

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

B) 0 black-eyed:1 orange-eyed

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

B) 1/6 + 1/6 = 1/3

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%

B) 25%

57) According to scientists, about what percentage of men currently living in Central Asia may be descended from the Mongolian ruler Genghis Khan? A) 4% B) 8% C) 12% D) 25% E) 40%

B) 8%

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.

B) DNA uses the nitrogenous base uracil.

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

B) DNA → RNA → protein

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.

B) Exons are spliced together.

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

B) Hershey and Chase

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.

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

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.

B) R plasmids.

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.

B) The cycle typically leads to the lysis of the host cell.

49) A lot of your DNA is inherited "junk": It doesn't code for any protein and has no known function in gene regulation. How do nucleotide sequences of "junk DNA" evolve? A) They evolve through natural selection. B) They evolve through genetic drift and other chance processes. C) They evolve to be more useful by taking on new functions. D) "Junk DNA" does not evolve. Changes in junk DNA sequences would not serve any purpose for an organism. E) They evolve by gradually being eliminated from the gene pool.

B) They evolve through genetic drift and other chance processes.

7) Who developed a theory of evolution almost identical to Darwin's? A) Lyell B) Wallace C) Aristotle D) Lamarck E) Mendel

B) Wallace

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

B) by altering the plants' growth

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.

B) codominance.

34) A person with AB blood illustrates the principle of A) incomplete dominance. B) codominance. C) pleiotropy. D) polygenic inheritance. E) blending inheritance.

B) codominance.

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.

B) do not follow the laws of independent assortment.

18) Humans share several features with salamanders. Certain genes and proteins are nearly identical between the two species; both species have four limbs with a similar skeletal structure; the species' early embryos are very similar; and where the salamander has a functional tail, humans have a vestigial tailbone. In evolutionary terms, these are examples of A) biogeographic similarity. B) homology. C) independently acquired characteristics. D) adaptation by natural selection. E) coincidental similarity.

B) homology.

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

B) hypercholesterolemia

40) Large antlers in male elk, which are used for battles between males, are a good example of a trait favored by A) intersexual selection. B) intrasexual selection. C) disruptive selection. D) directional selection. E) stabilizing selection.

B) intrasexual selection.

53) Any gene located on a sex chromosome A) is called a recessive gene. B) is called a sex-linked gene. C) is called a dominant allele. D) will exhibit pleiotropy. E) will exhibit codominance.

B) is called a sex-linked gene.

46) Frequency-dependent selection, as seen in the case of the scale-eating fish in Lake Tanganyika, tends to A) eliminate rare alleles and favor whichever allele is initially most frequent. B) maintain two phenotypes in a dynamic equilibrium in a population. C) produce random changes in allele frequencies. D) lead to heterozygote advantage. E) stimulate new mutations.

B) maintain two phenotypes in a dynamic equilibrium in a population.

56) Sex-linked conditions are more common in men than in women because A) men acquire two copies of the defective gene during fertilization. B) men need to inherit only one copy of the recessive allele for the condition to be fully expressed. C) women simply do not develop the disease regardless of their genetic composition. D) the sex chromosomes are more active in men than in women. E) the genes associated with the sex-linked conditions are linked to the Y chromosome, which determines maleness.

B) men need to inherit only one copy of the recessive allele for the condition to be fully expressed.

25) In the Hardy-Weinberg equation, the frequency of homozygous dominant individuals in a population is equal to A) q or p. B) p2. C) 2pq. D) q2. E) 2p.

B) p2.

46) Viral DNA incorporated into host cell DNA is known as a(n) A) capsid. B) prophage. C) envelope. D) phage. E) genome.

B) prophage.

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.

B) recessive alleles.

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

B) recombines linked . . . alleles

20) Deep branch points near the base, or trunk, of an evolutionary tree represent ________, while branch points near the tips of the branches represent ________. A) relatively recent common ancestors . . . relatively ancient common ancestors B) relatively ancient common ancestors . . . relatively recent common ancestors C) organisms that share homologous structures . . . organisms that do not share any homologous structures D) organisms with relatively simple traits . . . organisms with very complex traits E) complex organisms . . . simpler organisms

B) relatively ancient common ancestors . . . relatively recent common ancestors

21) The transfer of genetic information from DNA to RNA is called A) translation. B) transcription. C) initiation. D) elongation. E) promotion.

B) transcription.

26) Which of the following terms represents the frequency of heterozygotes in a population that is in Hardy-Weinberg equilibrium? A) p B) q C) 2pq D) q2 E) p2

C) 2pq

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

C) 3

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.

C) 4 amino acids.

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

C) 50% of the parent DNA.

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

C) A terminator

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.

C) An mRNA molecule transcribed from DNA is shorter than the genetic message it carries.

50) Mothers and teachers have often said they need another pair of eyes on the backs of their heads. And another pair of hands would come in handy in many situations. You can imagine that these traits would have been advantageous to our early hunter-gatherer ancestors as well. According to sound evolutionary reasoning, what is the most likely explanation for why humans do not have these traits? A) Because they actually would not be beneficial to the fitness of individuals who possessed them. Natural selection always produces the most beneficial traits for a particular organism in a particular environment. B) Because every time they have arisen before, the individual mutants bearing these traits have been killed by chance events. Chance and natural selection interact. C) Because these variations have probably never appeared in a healthy human. As tetrapods we are pretty much stuck with a four-limbed, two-eyed body plan; natural selection can only edit existing variations. D) Because humans are a relatively young species. If we stick around and adapt for long enough, it is inevitable that the required adaptations will arise. E) Because it is physically impossible to have a six-limbed organism with more than one set of eyes. Natural selection cannot break physical laws.

C) Because these variations have probably never appeared in a healthy human. As tetrapods we are pretty much stuck with a four-limbed, two-eyed body plan; natural selection can only edit existing variations.

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

C) Dd and Dd

14) Which of the following statements regarding natural selection is false? A) Natural selection is more of an editing process than a creative mechanism. B) Natural selection depends on the local environment at the current time. C) Natural selection starts with the creation of new alleles that are directed toward improving an organism's fitness. D) Natural selection and evolutionary change can occur in a short period of time (a few generations). E) Natural selection can be observed working in organisms alive today.

C) Natural selection starts with the creation of new alleles that are directed toward improving an organism's fitness.

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.

C) Sickle-cell disease causes white blood cells to be sickle-shaped.

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.

C) The dod idn ote at.

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.

C) The ribosomes of prokaryotes and eukaryotes are the same in structure and function.

12) Which of the following thinkers argued that organisms tend to produce many more offspring than the environment can support, leading to a struggle for existence, an argument that later influenced Charles Darwin's ideas of natural selection? A) Aristotle B) Charles Lyell C) Thomas Malthus D) Jean-Baptiste Lamarck E) Gregor Mendel

C) Thomas Malthus

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.

C) Very few new human diseases have originated in other animals because the genetic differences are too great.

48) The sex chromosome complement of a normal human male is A) XO. B) XX. C) XY. D) YY. E) YO.

C) XY.

52) What kind of virus is HIV? A) a herpesvirus B) a paramyxovirus C) a retrovirus D) a complex virus E) a provirus

C) a retrovirus

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. D) a site where DNA replication can begin. E) genes for enzymes that confer resistance to antibiotics.

C) a site for making the proteins needed for conjugation.

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.

C) a twisted rope ladder.

17) Which of the following disciplines has found evidence for evolution based on the native distributions (locations) of living species? A) molecular biology B) comparative anatomy C) biogeography D) paleontology E) embryology

C) biogeography

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 D) codon recognition → peptide bond formation → termination → translocation E) peptide bond formation → translocation → codon recognition → termination

C) codon recognition → peptide bond formation → translocation → termination

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

C) easy viral transmission from person to person

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

C) in the cytoplasm

6) The monomers of DNA and RNA are A) amino acids. B) monosaccharides. C) nucleotides. D) fatty acids. E) nucleic acids.

C) nucleotides.

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

C) only the 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.

C) shorten the time necessary for DNA replication.

58) Female inheritance patterns cannot be analyzed by simply studying the X chromosome because A) the X chromosome is too fragile for long-term analysis. B) the X chromosome is too susceptible to mutations. C) the X chromosome is obtained from both father and mother. D) the X chromosome is too difficult to isolate from the other chromosomes. E) the X chromosome is physically too large to analyze accurately.

C) the X chromosome is obtained from both father and mother.

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. E) the function of each polypeptide is to regulate the synthesis of each corresponding gene.

C) the function of an individual gene is to dictate the production of a specific polypeptide.

54) Recessive X-linked traits are more likely to be expressed in a male fruit fly than a female fruit fly because A) males are haploid. B) the male's SRY gene doubles the chances that sex-linked genes are expressed. C) the male's phenotype results entirely from his single X-linked gene. D) the male chromosome is more fragile than the female chromosome. E) the male chromosome is more susceptible to mutations.

C) the male's phenotype results entirely from his single X-linked 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.

C) three-nucleotide sequences.

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

C) transduction

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

C) transformation

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

D) 7:7:1:1

6) Lyell's book Principles of Geology, which Darwin read on board the H.M.S. Beagle, argued in favor of which of the following concepts? A) Earth's surface is shaped mainly by occasional catastrophic events. B) Earthquakes were less important than sedimentary processes in creating the landscape of South America. C) Meteorite impacts may have been a major cause of periodic mass extinctions. D) Earth's surface is shaped by natural forces that act gradually and are still acting. E) The processes that shape Earth today are very different from those that were at work in the past.

D) Earth's surface is shaped by natural forces that act gradually and are still acting.

52) What is meant by the statement that "male bees are fatherless"? A) Male bees don't play a role in the rearing of bee young. B) Male bees are produced by budding. C) Male bees develop from fertilized eggs. D) Male bees develop from unfertilized eggs. E) The queen bee's mate dies before the male eggs hatch.

D) Male bees develop from unfertilized eggs.

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.

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.

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.

D) The blending hypothesis suggests that all of the traits of the offspring come from either the mother or the father.

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.

D) The doe did not eat.

55) A color-blind woman marries a man who is not color-blind. All of their sons, but none of their daughters, are color-blind. Which of the following statements correctly explains these results? A) The gene for color vision is incompletely dominant to the gene for sex determination. B) The gene for color vision is completely dominant to the gene for sex determination. C) The gene for color vision is codominant with the gene for sex determination. D) The gene for color vision is linked to the X chromosome. E) The gene for color vision is linked to the Y chromosome.

D) The gene for color vision is linked to the X chromosome.

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.

D) The hybrid offspring of a cross are the P1 generation.

Desert pupfish live in springs of the American Southwest. Today there are about 30 species of pupfish, but they all evolved from a common Pleistocene ancestor. The southwestern United States was once much wetter than it is now, and the Pleistocene pupfish flourished over a wide geographic area. Over thousands of years, however, the Sierra Nevada Mountain range was pushed upward by geological forces, blocking rainfall from the Pacific Ocean. As the large lakes dried up, small groups of pupfish remained in springs and pools fed by groundwater seepage. Now, although many of these small springs still have pupfish, each population has evolved to become very different from pupfish in other springs. 1) Which of the following statements represents the most probable explanation for the differences between pupfish populations? A) The types of genes in the population increased. B) The frequency of genotypes reached equilibrium. C) New genes entered the population through migration. D) The isolated populations had a restricted gene pool. E) Each new species contains all the original genotypes of the larger populations.

D) The isolated populations had a restricted gene pool.

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.

D) The lysogenic cycle typically results in the rapid lysis of all infected cells.

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.

D) Transcription occurs in the cytoplasm of eukaryotic cells.

43) A protein shell enclosing a viral genome is known as a(n) A) capsule. B) envelope. C) phage. D) capsid. E) prophage.

D) capsid.

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

D) dominant to

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.

D) each pair of alleles segregates independently of the other pairs of alleles during gamete formation.

21) Darwin was the first person to draw an evolutionary tree, a diagram that represents A) records of breeding in domesticated animals. B) records of lineages in humans (also known as a family tree). C) final, factually established evolutionary relationships among different groups of organisms. D) evidence-based hypotheses regarding our understanding of patterns of evolutionary descent. E) groupings of organisms based on overall similarity.

D) evidence-based hypotheses regarding our understanding of patterns of evolutionary descent.

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

D) incompletely dominant

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.

D) increase their genetic diversity.

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

D) initiation of a new RNA molecule

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.

D) mutagen.

36) Which of the following will tend to produce adaptive changes in populations? A) genetic drift B) gene flow C) mutation D) natural selection E) the founder effect

D) natural selection

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.

D) occurs when a phage transfers bacterial DNA from one bacterium to another.

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

D) polygenic inheritance

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

D) reverse transcriptase

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). 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.

D) the alleles for color and vision segregate independently during gamete formation.

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.

D) uses each strand of a DNA molecule as a template for the creation of a new strand.

Exposure to the HIV virus doesn't necessarily mean that a person will develop AIDS. Some people have genetic resistance to infection by HIV. Dr. Stephen O'Brien from the U.S. National Cancer Institute has recently identified a mutant form of a gene, called CCR5, that can protect against HIV infection. The mutation probably originated in Europe among survivors of the bubonic plague. The mutated gene prevents the plague bacteria from attaching to cell membranes and, therefore, from entering and infecting body cells. Although the HIV virus is very different from the bacteria that causes the plague, both diseases affect the exact same cells and use the same method of infection. The presence of the mutated gene in descendants of plague survivors helps prevent them from contracting AIDS. Pharmaceutical companies are using this information as the basis for a new approach to AIDS prevention. This would be very important in areas of the world where the mutation is scarce or absent, such as Africa. 2) Which of the following shows the steps of a viral infection in the proper order? A) virus locates host cell → enters nucleus → alters host cell DNA → destroys cell membrane B) virus locates host cell → alters host cell DNA → host cell produces copies of virus → copies enter host cell nucleus → nucleus leaves cell C) virus kills host cell → enters nucleus → replaces all host DNA → releases copies of virus D) virus locates host cell → penetrates cell membrane → enters nucleus → alters host cell DNA → host cell produces copies of virus E) virus locates host cell → forms hydrogen bonds → changes DNA to RNA→ host cell produces copies of virus

D) virus locates host cell → penetrates cell membrane → enters nucleus → alters host cell

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

E) 9:3:3:1

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.

E) 9:3:3:1.

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

E) DNA polymerase

14) If one strand of DNA is CGGTAC, the corresponding strand would be A) GCCTAG. B) CGGTAC. C) GCCAUC. D) TAACGT. E) GCCATG.

E) GCCATG.

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.

E) The DNA molecule would have irregular widths along its length.

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.

E) The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine.

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.

E) The sequence of nucleotides along the length of a DNA strand is restricted by the base-pairing rules.

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.

E) There are many successful ways to rid infected plants of a virus.

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.

E) There is no known treatment or cure for prion infections.

23) Microevolution, or evolution at its smallest scale, occurs when A) an individual's traits change in response to environmental factors. B) a geographic area is altered by erosion, volcanic eruptions, or other geological forces. C) a community of organisms changes due to the extinction of several dominant species. D) a new species arises from an existing species. E) a population's allele frequencies change over a span of generations.

E) a population's allele frequencies change over a span of generations.

Exposure to the HIV virus doesn't necessarily mean that a person will develop AIDS. Some people have genetic resistance to infection by HIV. Dr. Stephen O'Brien from the U.S. National Cancer Institute has recently identified a mutant form of a gene, called CCR5, that can protect against HIV infection. The mutation probably originated in Europe among survivors of the bubonic plague. The mutated gene prevents the plague bacteria from attaching to cell membranes and, therefore, from entering and infecting body cells. Although the HIV virus is very different from the bacteria that causes the plague, both diseases affect the exact same cells and use the same method of infection. The presence of the mutated gene in descendants of plague survivors helps prevent them from contracting AIDS. Pharmaceutical companies are using this information as the basis for a new approach to AIDS prevention. This would be very important in areas of the world where the mutation is scarce or absent, such as Africa. 1) The most likely method by which the mutated CCR5 gene prevents AIDS is by A) covering the cell membrane. B) rupturing the nuclear membrane. C) attacking and destroying the HIV virus particles. D) blocking transfer RNA from reaching the viral ribosomes. E) coding for a protective protein in the cell membrane.

E) coding for a protective protein in the cell membrane.

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

E) heavy use of antibiotics in medicine and in agriculture

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

E) joining to only one specific type of amino acid

48) In a particular environment, there are no fitness differences among individuals with dark hair and individuals with light hair. The term that best describes this situation is A) random mating. B) random selection. C) natural selection. D) differential reproductive success. E) neutral variation.

E) neutral variation.

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

E) the fact that some amino acids are specified from more than one codon

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

E) the frequencies with which the corresponding traits occur together in offspring

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

E) the same locus on homologous

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.

E) true-breeding.

54) HIV does the greatest damage to A) the adrenal glands. B) pancreatic cells. C) nervous tissue. D) gametes. E) white blood cells.

E) white blood cells.

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.

A) Incomplete dominance supports the blending hypothesis.

15) Which of the following would prevent an organism from becoming part of the fossil record when it dies? A) It is fully decomposed by bacteria and fungi. B) It is buried in fine sediments at the bottom of a lake. C) It gets trapped in sap. D) It falls into an acid bog. E) It is frozen in ice.

A) It is fully decomposed by bacteria and fungi.

11) Which of the following assumptions or observations contradicts Darwin's idea of natural selection? A) Whether an organism survives and reproduces is almost entirely a matter of random chance. B) Heritable traits that promote successful reproduction should gradually become more common in a population. C) Populations produce more offspring than their environment can support. D) Organisms compete for limited resources. E) Organisms vary in heritable ways.

A) Whether an organism survives and reproduces is almost entirely a matter of random chance.

22) A population is A) a group of individuals of the same species living in the same place at the same time. B) all individuals of a species, regardless of location or time period in which they live. C) a group of individuals of different species living in the same place at the same time. D) a group of individuals of a species plus all of the other species with which they interact. E) a group of species that share a common characteristic.

A) a group of individuals of the same species living in the same place at the same time.

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.

A) a mating between an individual of unknown genotype and an individual homozygous recessive for the trait of interest.

10) Which of the following best expresses the concept of natural selection? A) differential reproductive success based on inherited characteristics B) inheritance of acquired characteristics C) change in response to need D) a process of constant improvement, leading eventually to perfection E) survival of the fittest

A) differential reproductive success based on inherited characteristics

39) A rabbit population consists of animals that are either very dark on top or very light on top. The color pattern is not related to sex. No rabbit shows intermediate coloration (medium darkness). This pattern might result from A) disruptive selection. B) directional selection. C) stabilizing selection. D) sexual selection. E) random mating.

A) disruptive selection.

51) Given the sex determination system in bees, we can expect that A) female bees will produce eggs by meiosis, while male bees will produce sperm by mitosis. B) female bees will produce eggs by mitosis, while male bees will produce sperm by meiosis. C) male and female bees will produce sperm and eggs by meiosis. D) male and female bees will produce sperm and eggs by mitosis. E) female bees will produce eggs by meiosis, but male bees will not produce sperm.

A) female bees will produce eggs by meiosis, while male bees will produce sperm by mitosis.

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

A) heterozygous for the trait and able

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.

A) incomplete dominance.

24) The ultimate source of all new alleles is A) mutation in parent cells (asexual organisms) or in cells that produce gametes (sexual organisms). B) any form of mutation, regardless of the cell type. C) chromosomal duplication. D) genetic drift. E) natural selection.

A) mutation in parent cells (asexual organisms) or in cells that produce gametes (sexual organisms).

4) Mendel conducted his most memorable experiments on A) peas. B) roses. C) guinea pigs. D) fruit flies. E) clones.

A) peas.

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.

B) Chorionic villus sampling is typically performed later in the pregnancy than amniocentesis.

45) The sickle-cell allele produces a serious blood disease in homozygotes. Why doesn't natural selection eliminate this allele from all human populations? A) Natural selection is a positive force, so it does not eliminate alleles. B) In populations where endemic malaria is present, heterozygotes have an important advantage: They are resistant to malaria and therefore are more likely to survive and produce offspring that carry the allele. C) Genetic drift tends to keep the allele present in human populations. D) Mutations keep bringing the allele back into circulation. E) Natural selection occurs very slowly, but elimination of the sickle-cell allele is expected to occur soon.

B) In populations where endemic malaria is present, heterozygotes have an important advantage: They are resistant to malaria and therefore are more likely to survive and produce offspring that carry the allele.

32) A population of 1,000 birds exists on a small Pacific island. Some of the birds are yellow, a characteristic determined by a recessive allele. The others are green, a characteristic determined by a dominant allele. A hurricane on the island kills most of the birds from this population. Only ten remain, and those birds all have yellow feathers. Which of the following statements is true? A) Assuming that no new birds come to the island and no mutations occur, future generations of this population will contain both green and yellow birds. B) The hurricane has caused a population bottleneck and a loss of genetic diversity. C) This situation illustrates the principle of adaptive radiation. D) This situation illustrates the effect of a mutation event. E) The ten remaining birds will mate only with each other, and this will contribute to gene flow in the population.

B) The hurricane has caused a population bottleneck and a loss of genetic diversity.

13) A dog breeder wishes to develop a breed that does not bark. She starts with a diverse mixture of dogs. Generation after generation, she allows only the quietest dogs to breed. After 30 years of work she has a new breed of dog with interesting traits, but on average, the dogs still bark at about the same rate as other dog breeds. Which of the following would be a logical explanation for her failure? A) There is no variation for the trait (barking). B) The tendency to bark is not a heritable trait. C) The selection was artificial, not natural, so it did not produce evolutionary change. D) There was no selection (differential reproductive success) related to barking behavior. E) She did not breed enough of the frequently barking dogs to obtain the desired result.

B) The tendency to bark is not a heritable trait.

47) Tay-Sachs is inherited as an autosomal recessive allele. Homozygous individuals die within the first few years of life. However, there is some evidence that heterozygous individuals are more resistant to tuberculosis. Which of the following statements about Tay-Sachs is true? A) The allele for Tay-Sachs is selected against. B) This situation is an example of heterozygote advantage if tuberculosis is present in a population. C) This situation is an example of directional selection. D) This situation is an example of disruptive selection. E) Heterozygotes will be more fit than either homozygote regardless of environmental conditions.

B) This situation is an example of heterozygote advantage if tuberculosis is present in a population.

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.

B) applies to all sexually reproducing organisms.

9) Broccoli, cabbages, and brussels sprouts all descend from the same wild mustard and can still interbreed. These varieties were produced by A) speciation. B) artificial selection. C) natural selection. D) genetic drift. E) inheritance of acquired characteristics.

B) artificial selection.

27) Which of the following conditions would tend to make the Hardy-Weinberg equation more accurate for predicting the genotype frequencies of future generations in a population of a sexually reproducing species? A) a small population size B) little gene flow with surrounding populations C) a tendency on the part of females to mate with the healthiest males D) frequent interbreeding with individuals from a second population with different values of p and q E) mutations that alter the gene pool

B) little gene flow with surrounding populations

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.

B) not affected at all by the disease.

28) Imagine that you are studying a very large population of moths that is isolated from gene flow. A single gene controls wing color. Half of the moths have white-spotted wings (genotype WW or Ww) and half of the moths have plain brown wings (ww). There are no new mutations, individuals mate randomly, and there is no natural selection on wing color. How will p, the frequency of the dominant allele, change over time? A) p will increase; the dominant allele will eventually take over and become most common in the population. B) p will neither increase nor decrease; it will remain more or less constant under the conditions described. C) p will decrease because of genetic drift. D) p will increase initially, then decrease until the W allele vanishes from the population. E) p will fluctuate rapidly and randomly because of genetic drift.

B) p will neither increase nor decrease; it will remain more or less constant under the conditions described.

37) An elk herd is observed over many generations. Most of the full-grown bull elk have antlers of nearly the same size, although a few have antlers that are significantly larger or smaller than this average size. The average antler size remains constant over the generations. Which of the following effects probably accounts for this situation? A) directional selection B) stabilizing selection C) a bottleneck effect that resulted in low genetic diversity D) a founder effect E) a high rate of gene flow

B) stabilizing selection

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.

B) the behavior of chromosomes during meiosis and fertilization accounts for patterns of inheritance.

19) Which of the following represents a pair of homologous structures? A) the wing of a bat and the scales of a fish B) the wing of a bat and the flipper of a whale C) the antennae of an insect and the eyes of a bird D) the feathers of a bird and the wing membrane of a bat E) the wing of a bat and the wing of a butterfly

B) the wing of a bat and the flipper of a whale

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.

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.

8) During the 1950s, a scientist named Lysenko tried to solve the food shortages in the Soviet Union by breeding wheat that could grow in Siberia. He theorized that if individual wheat plants were exposed to cold, they would develop additional cold tolerance and pass it to their offspring. Based on the ideas of artificial and natural selection, do you think this project worked as planned? A) Yes, the wheat probably evolved better cold tolerance over time through inheritance of acquired characteristics. B) No, because Lysenko took his wheat seeds straight to Siberia instead of exposing them incrementally to cold. C) No, because there was no process of selection based on inherited traits. Lysenko assumed that exposure could induce a plant to develop additional cold tolerance and that this tolerance would be passed to the plant's offspring. D) No, because Lysenko used wheat varieties that had lost their cold tolerance as a result of disuse. E) Yes, because this is generally the method used by plant breeders to develop new crops.

C) No, because there was no process of selection based on inherited traits. Lysenko assumed that exposure could induce a plant to develop additional cold tolerance and that this tolerance would be passed to the plant's offspring.

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.

C) a breeding experiment in which the parental varieties

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

C) by the number of chromosomes

38) After a copper smelter begins operation, local populations of plants downwind of the plant begin to adapt to the resulting air pollution. Scientists document, for example, that the acid tolerance of several plant species has increased significantly in the polluted area. This is an example of a response to A) stabilizing selection. B) disruptive selection. C) directional selection. D) genetic drift. E) heterozygote advantage.

C) directional selection.

30) Genetic drift resulting from a disaster that drastically reduces population size is called A) natural selection. B) gene flow. C) the bottleneck effect. D) nonrandom mating. E) the founder effect.

C) the bottleneck effect.

1) Which of the following statements regarding domestic dogs is false? A) Dogs originated in East Asia. B) Dogs of different breeds can be identified through genetic analysis. C) Shar-pei and Akita are genetically very similar to the wolf. D) All dogs are descended from wolves. E) Humans have bred dogs for thousands of years.

D) All dogs are descended from wolves.

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.

D) An allele that is fully expressed is referred to as recessive.

43) If you had to choose, where would you rather get infected with a serious bacterial disease? A) In a hospital, where most of the bacteria are probably already weakened by antibiotics in the environment. B) In a livestock barn where the animals have been treated with antibiotics. C) In a big city where antibiotics are routinely prescribed by doctors. D) In a remote, sparsely populated area where the bacteria have not been exposed to antibiotic drugs. E) It doesn't make any differencea serious bacterial illness is going to have a similar impact on your health regardless of where you pick it up.

D) In a remote, sparsely populated area where the bacteria have not been exposed to antibiotic drugs.

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

D) karyotyping . . . biochemical testing

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

D) linked . . . do not sort independently during meiosis

31) In populations of the greater prairie chicken in Illinois, genetic diversity was A) lost through mutation and restored by natural selection. B) lost through genetic drift and restored by natural selection. C) lost through gene flow and restored by mutation. D) lost through genetic drift and restored by gene flow. E) lost through directional selection and restored by balancing selection.

D) lost through genetic drift and restored by gene flow.

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

D) one X chromosome and one Y chromosome

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

D) polygenic inheritance

35) Which sentence best describes the true nature of natural selection? A) Survival of the fittest. B) Only the strongest survive. C) The strong eliminate the weak in the race for survival. D) Organisms change by random chance. E) Heritable traits that promote reproduction become more frequent in a population from one generation to the next.

E) Heritable traits that promote reproduction become more frequent in a population from one generation to the next.

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.

E) Most human genetic diseases are treatable if caught early.

42) A woman struggling with a bacterial illness is prescribed a month's supply of a potent antibiotic. She takes the antibiotic for about two weeks and feels much better. Should she save the remaining two-week supply, or should she continue taking the drug? A) She should save the drug for later, because if she keeps taking it the bacteria will evolve resistance. B) She should save the drug for use the next time the illness strikes. C) She should save the drug because antibiotics are in short supply and she may need it to defend herself against a bioterrorism incident. D) She should continue taking the drug because otherwise the bacteria will evolve by genetic drift. E) She should continue taking the drug until her immune system can completely eliminate the infection. Otherwise the remaining bacteria in her system may recover, and they will probably be resistant.

E) She should continue taking the drug until her immune system can completely eliminate the infection. Otherwise the remaining bacteria in her system may recover, and they will probably be resistant.

16) Which of the following statements regarding the currently available fossil record is false? A) The currently available fossil record shows that the earliest fossils of life are about 3.5 billion years old. B) The currently available fossil record shows that younger strata were laid down on top of older strata. C) The currently available fossil record shows that single-celled eukaryotes appeared before multicellular eukaryotes. D) The currently available fossil record documents gradual evolutionary changes that link one group of organisms to another. E) The currently available fossil record shows that the first life forms were eukaryotes.

E) The currently available fossil record shows that the first life forms were eukaryotes.

45) The mechanism that "breaks" the linkage between linked genes is A) incomplete dominance. B) pleiotropy. C) codominance. D) independent assortment. E) crossing over.

E) crossing over.

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.

E) genetics and the environment.