Part 2

Question 1

Which of the following choices represents the genotype of an individual diploid organism?
a. BbCCdd c. bcd
b. BCd d. BbCd

Answer 1

a. BbCCdd

Question 2

An allele is
a. a version of a gene.
b. a trait that can be affected by the external environment.
c. always codominant to its counterpart in another chromosome.
d. the result of a change in phenotype

Answer 2

a. a version of a gene.

Question 3

Which of the following does NOT represent a phenotype?
a. a person’s susceptibility to Addison’s disease
b. the height of a draft horse
c. the alleles in a mouse that control hair color
d. the extent to which an individual is shy

Answer 3

c. the alleles in a mouse that control hair color

Question 4

Which of the following statements regarding genes is NOT true?
a. Genes are located on chromosomes.
b. Genes consist of a long sequence of DNA.
c. Genes are the basic unit of information affecting a genetic trait.
d. In sexually reproducing species, each cell contains a single copy of every gene

Answer 4

d. In sexually reproducing species, each cell contains a single copy of every gene

Question 5

Which of the following statements is NOT true?
a. Two organisms with the same phenotype may have different genotypes.
b. Two organisms with the same genotype are homozygous.
c. A heterozygous organism may have the same phenotype as a homozygous organism.
d. A heterozygous organism has fewer alleles for a given gene than a homozygous organism.

Answer 5

b. Two organisms with the same genotype are homozygous.

Question 6

A thoroughbred racehorse could have at most ________ alleles of the same gene.
a. 16 c. 4
b. 8 d. 2

Answer 6

d. 2

Question 7

Which of the following is true for mutations?
a. Mutations will affect the genotype without affecting the phenotype.
b. Mutations will affect the phenotype without affecting the genotype.
c. Mutations will affect the genotype, which may affect the phenotype.
d. Mutations will affect the phenotype, which may affect the genotype.

Answer 7

c. Mutations will affect the genotype, which may affect the phenotype.

Question 8

If you compare a sperm cell in a human to a skin cell from the same individual, which of the following
differences would you expect to find?
a. The sperm cell would contain four alleles for a given gene; the skin cell would contain two
alleles.
b. The sperm cell would contain only one allele for a given gene; the skin cell would contain
two alleles.
c. Both sperm and skin cells may carry different alleles for an individual gene.
d. Both sperm and skin cells would contain 46 chromosomes found as homologous pairs.

Answer 8

b. The sperm cell would contain only one allele for a given gene; the skin cell would contain
two alleles.

Question 9

Which of the following statements is true of Mendel’s laws?
a. They are less accurate than Punnett square results.
b. They are useful only in unusual situations.
c. They correctly explain how genes are inherited.
d. They correctly predict the phenotype of an organism.

Answer 9

c. They correctly explain how genes are inherited.

Question 10

When Mendel proposed the law of segregation, which of the following pieces of information did he NOT
have?
a. data on the outcomes of crossing two true-breeding pea plants
b. ratios to predict the outcome of crossing two heterozygous pea plants
c. a prediction for how a single trait is inherited
d. knowledge of the location of the alleles for flower color

Answer 10

d. knowledge of the location of the alleles for flower color

Question 11

Which of the following did Gregor Mendel notice in garden peas?
a. Some plants always produced offspring with flowers that were the same color as the
parent plant’s flowers.
b. The first generation from a genetic cross of true-breeding plants always produced
offspring that were intermediate in their phenotype and did not look like either parent.
c. Garden peas always produce a variety of phenotypes in their offspring, which result from
frequent mutations.
d. Any individual pea plant carries at least three different alleles for flower color.

Answer 11

a. Some plants always produced offspring with flowers that were the same color as the
parent plant’s flowers.

Question 12

Which of the following expresses Mendel’s law of segregation?
a. All dominant alleles of different genes divide into different cells from the recessive alleles.
b. Two alleles of a gene separate during meiosis and end up in different gametes.
c. When gametes form, the genes originally from one parent all end up in different gametes
from the genes originally from the other parent.
d. Gametes with recessive alleles will fuse only with each other.

Answer 12

b. Two alleles of a gene separate during meiosis and end up in different gametes.

Question 13

A Punnett square is used to
a. determine the source of new alleles.
b. determine how many genes control a given trait.
c. predict the gametes that will be produced by an organism.
d. predict the outcome of a genetic cross.

Answer 13

d. predict the outcome of a genetic cross.

Question 14

Two organisms that are true-breeding for a certain genetic characteristic are mated and
their offspring analyzed. Which of the following statements about this situation is true?
a. Both parents are heterozygotes.
b. The offspring are either 100 percent homozygotes or 100 percent heterozygotes.
c. The offspring represent the P generation.
d. The gametes produced by the offspring will carry two alleles for this gene

Answer 14

b. The offspring are either 100 percent homozygotes or 100 percent heterozygotes.

Question 15

A pea plant that is heterozygous for the flower color gene makes gametes. What is the
probability that a specific gamete contains the recessive allele for flower color?
a. 0 percent c. 50 percent
b. 25 percent d. 75 percent

Answer 15

c. 50 percent

Question 16

Consider a gene with two alleles that show complete dominance. When two heterozygotes for this gene
breed, they have a 25 percent chance of producing a homozygous recessive offspring. The next time these
two individuals breed, what are the chances that they will once again have a homozygous recessive
progeny?
a. 0 percent c. 50 percent
b. 25 percent d. 75 percent

Answer 16

b. 25 percent

Question 17

Two genes control fur color in Labrador retrievers. The first gene determines whether the pigment to be
deposited in the hairs will be black or brown. The second gene determines whether the pigments are put
into the dog’s hairs at all. A dog homozygous for the recessive allele of this second gene will be yellow
because no pigment is deposited in its hairs. This is an example of
a. epistasis. c. codominance.
b. pleiotropy. d. incomplete dominance.

Answer 17

a. epistasis.

Question 18

Most human genetic characters are
a. controlled by one gene. c. controlled by more than one gene.
b. not inherited according to Mendel’s laws. d. not heritable

Answer 18

c. controlled by more than one gene.

Question 19

One of the first medical tests a newborn receives determines if the child has phenylketonuria (PKU). PKU
is the result of a mutation in a single gene that causes mental retardation and a host of other phenotypes
(light hair and skin color, eczema, and a “mousy” smell). By detecting PKU early, doctors are able to
reduce the effect of this condition with a modified diet. PKU is an example of
a. epistasis. c. pleiotropy.
b. a polygenic trait. d. codominance.

Answer 19

c. pleiotropy.

Question 20

Which of the following statements is NOT true?
a. Traits that are determined by the effect of more than one gene are known as polygenic.
b. Environmental factors can alter the effects of genes.
c. Most traits are under the control of more than one gene.
d. A genotype is always expressed in the phenotype.

Answer 20

d. A genotype is always expressed in the phenotype.

Question 21

Two copies of the same gene on a single chromosome would indicate a(n) ________ had occurred.
a. deletion c. inversion
b. duplication d. translocation

Answer 21

b. duplication

Question 22

Which of the following would explain two chromosomes in an individual cell that contain some, but not
all, of the same genes at the same loci?
a. Both of the chromosomes are paternal.
b. Both of the chromosomes are maternal.
c. The chromosomes are from a common ancestor.
d. A chromosomal alteration has occurred.

Answer 22

d. A chromosomal alteration has occurred.

Question 23

A ________ is a chart that shows genetic relationships within a family over several generations.
a. karyotype c. Punnett square
b. pedigree d. single-gene disorder map

Answer 23

b. pedigree

Question 24

Humans have ________ pairs of homologous chromosomes.
a. 46 c. 22
b. 23 d. 44

Answer 24

b. 23

Question 25

A karyotype shows a chromosomal abnormality that does not change the length of any of the
chromosomes. Which abnormality is indicated?
a. inversion c. translocation
b. deletion d. duplication

Answer 25

a. inversion

Question 26

On chromosomes within an individual, there are ________ alleles for a given gene found on ________
chromosomes.
a. two; homologous c. four; paternal
b. four; maternal d. two; Y

Answer 26

a. two; homologous

Question 27

Chromosomes that are NOT involved in determining gender are known as
a. autosomes. c. homologues.
b. sex chromosomes. d. linked.

Answer 27

a. autosomes

Question 28

Which of the following statements about homologous chromosomes is true?
a. There are 46 pairs in humans.
b. They contain the same genes in the same locations.
c. They contain identical alleles in the same location.
d. They are also known as sex chromosomes

Answer 28

b. They contain the same genes in the same locations.`

Question 29

One chromosomal abnormality that is usually fatal is
a. a mutation in a gene.
b. an exchange of material between homologous chromosomes.
c. extra copies of sex chromosomes.
d. the addition of an extra autosomal chromosome.

Answer 29

d. the addition of an extra autosomal chromosome.

Question 30

Which of the following must be true for a woman who is heterozygous for a given gene?
a. She must be heterozygous for all genes.
b. All of her eggs will contain both of the alleles for that gene.
c. All of her eggs will contain one allele or the other, but not both alleles.
d. She carries a rare mutation

Answer 30

c. All of her eggs will contain one allele or the other, but not both alleles.

Question 31

During cell division a piece of a chromosome breaks off and reattaches to the same chromosome, but the
piece is now in reverse order. How would this abnormality affect the chromosome?
a. An extra copy of the chromosome will be made to ensure normal function.
b. The inverted section will be deleted to prevent problems.
c. The chromosome will take on a circular configuration.
d. Genes in the section that was inverted could lose normal function

Answer 31

d. Genes in the section that was inverted could lose normal function

Question 32

Which of the following genetic changes would NOT be passed from parent to child?
a. a mutation in a skin cell
b. the loss of a chromosome in a sperm cell
c. the addition of a chromosome in an egg cell
d. a translocation in a gamete

Answer 32

a. a mutation in a skin cell

Question 33

What information is NOT visible in a karyotype?
a. the individual’s sex
b. the number of autosomes
c. whether the individual carries genetic mutations
d. whether deletions have occurred

Answer 33

c. whether the individual carries genetic mutations

Question 34

n a karyotype of a male, which of the following would indicate an abnormality?
a. one X chromosome and one Y chromosome
b. three copies of chromosome 22
c. 22 pairs of autosomes
d. a total of 46 chromosomes

Answer 34

b. three copies of chromosome 22

Question 35

A karyotype of an individual with mild mental retardation shows three copies of the
X chromosome. If this individual decides to have children, how is her chromosomal abnormality likely to
affect her offspring?
a. All of her children will inherit an extra copy of the X chromosome.
b. Any female children have a 75 percent chance of inheriting an extra copy of an
X chromosome.
c. She will be unable to produce male children.
d. Half of her eggs will contain an extra copy of the X chromosome

Answer 35

d. Half of her eggs will contain an extra copy of the X chromosome

Question 36

A karyotype from an adult male indicates a chromosomal abnormality, which does not affect his health.
Which of the following abnormalities is most likely seen?
a. three copies of the X chromosome
b. no copies of chromosome 2
c. a translocation between chromosome 14 and chromosome 15
d. a deletion on chromosome 5

Answer 36

c. a translocation between chromosome 14 and chromosome 15

Question 37

In humans, X-linked genetic diseases
a. are associated with autosomes.
b. tend to be expressed more in females than males.
c. only affect males.
d. tend to be expressed more in males than in females.

Answer 37

d. tend to be expressed more in males than in females.

Question 38

The gender of a human child is determined by the
a. loci. c. autosomes.
b. egg. d. sperm.

Answer 38

d. . sperm

Question 39

In humans, the “master sex switch” that determines whether an embryo will become a male is the
a. X chromosome. c. SRY gene.
b. locus. d. androgen switch

Answer 39

c. SRY gene.

Question 40

Which of the following genotypes represents a human male?
a. XY c. XX
b. YY d. XO

Answer 40

a. XY

Question 41

The gene for a certain sex-linked trait is found only on the Y chromosome. If the male parent carries this
gene, which of the following statements about the inheritance of that trait is true?
a. The trait will be expressed in 100 percent of the female offspring.
b. The trait will be expressed in 50 percent of the female offspring.
c. The trait will be expressed in 100 percent of the male offspring.
d. The trait will be expressed in 50 percent of the male offspring.

Answer 41

c. The trait will be expressed in 100 percent of the male offspring.

Question 42

The X chromosome in humans is
a. found as a pair in females.
c. present only in females.
b. the only human sex chromosome.
d. always found in single copy

Answer 42

a. found as a pair in females

Question 43

A carrier is an individual with a ________ genotype who does not express the recessive trait but can pass
it along to offspring.
a. homozygous c. recessive
b. heterozygous d. dominant

Answer 43

b. heterozygous

Question 44

xWhy are X-linked recessive genetic disorders more commonly seen in males?
a. For an X-linked disorder to occur, an individual must receive one allele only found on the
X chromosome and a second allele found only on the Y chromosome, which
females do not have.
b. Females must receive two copies of the recessive allele to exhibit the disorder, but males
need only one copy.
c. The alleles of sex-linked genes are carried only on the Y chromosome, which females do
not have.
d. Females only have X chromosomes and genes on the X chromosome are not expressed.

Answer 44

b. Females must receive two copies of the recessive allele to exhibit the disorder, but males
need only one copy.

Question 45

If a father is affected by an X-linked condition and the mother is a carrier, what is the probability of their
children being affected?
a. All sons will be affected. c. All daughters will be affected.
b. Half of the sons will be affected. d. Half of the sons will be carriers.

Answer 45

b. Half of the sons will be affected.

Question 46

A female who is a carrier of the sex-linked gene A has the genotype
a. Aa. c. aa.
b. AA. d. XAXa.

Answer 46

d. XAXa.

Question 47

Most inherited human disorders are the result of
a. recessive mutations of genes located on autosomes.
b. dominant mutations of genes located on the X chromosome.
c. recessive mutations of genes located on the Y chromosome.
d. simultaneous mutations of the same gene on homologous chromosomes

Answer 47

a. recessive mutations of genes located on autosomes.

Question 48

If two parents are heterozygous for an autosomal recessive disease,
a. they are both considered genetic carriers for the disease.
b. their children have no chance of inheriting the disease.
c. their children have a 50 percent chance of inheriting the disease.
d. all of their children will also be heterozygous.

Answer 48

a. they are both considered genetic carriers for the disease.

Question 49

What information in a pedigree would indicate a condition is likely dominant?
a. Twenty-five percent of the individuals in the pedigree have the condition.
b. Two-thirds of the affected individuals are females.
c. None of the affected individuals have unaffected parents.
d. Most of the affected individuals are males

Answer 49

c. None of the affected individuals have unaffected parents.

Question 50

If a genetic disorder is caused by a dominant allele, individuals with which of the following genotypes
would be affected by the disorder?
a. AA and aa c. AA and Aa
b. aa and Aa d. AA, Aa, and aa

Answer 50

c. AA and Aa

Question 51

The two strands of a DNA molecule are held together by ________ bonds between their base pairs.
a. hydrogen c. phosphate
b. amino acid d. protein

Answer 51

a. hydrogen

Question 52

Along one side of a DNA molecule, the nucleotides are connected to each other by
a. covalent bonds between phosphate groups and sugar molecules.
b. hydrogen bonds between adenine and guanine.
c. covalent bonds between bases and sugar molecules.
d. hydrogen bonds between adjacent sugar molecules

Answer 52

a. covalent bonds between phosphate groups and sugar molecules.

Question 53

Which of the following is not a base found in DNA?
a. thymine c. guanine
b. adenine d. uracil

Answer 53

d. uracil

Question 54

What part of a nucleotide accounts for the genetic variation between individuals?
a. sugar c. base
b. phosphate d. polymerase

Answer 54

c. base

Question 55

How many phosphate groups are present in a single strand of DNA?
a. the same number as there are adenine bases
b. the same number as there are adenine + thymine bases
c. the same number as there are guanine + cytosine bases
d. the same number as there are adenine + thymine + guanine + cytosine bases

Answer 55

d. the same number as there are adenine + thymine + guanine + cytosine bases

Question 56

.If a segment of double-stranded DNA has 20 percent A, how much of it is C?
a. 20 percent c. 40 percent
b. 30 percent d. 60 percent

Answer 56

b. 30 percent

Question 57

When bases of DNA bind to the complementary strand
a. A always pairs with T. c. A always pairs with C.
b. A sometimes pairs with T. d. A sometimes pairs with C.

Answer 57

a. A always pairs with T

Question 58

In a strand of double-stranded DNA, C will always be bound with
a. A. c. C.
b. T. d. G.

Answer 58

d. G.

Question 59

f one strand of DNA has the sequence CGATT, the sequence of the other strand of the same molecule
will be
a. CGATT. c. TACGG.
b. GCTUU. d. GCTAA.

Answer 59

d. GCTAA

Question 60

When looking at a single-stranded piece of DNA,
a. G will always be next to C. c. G will sometimes be next to T.
b. G will always be next to G. d. G will never be next to A

Answer 60

c. G will sometimes be next to T.

Question 61

When examining the two complementary strands of nucleotides in one DNA molecule, you would expect
to find that
a. the sum of Gs and Cs in one strand would be equal to the sum of the Gs and Cs in the
other strand.
b. the sum of Ts and As in one strand would be equal to the sum of the Cs and Gs in the
other strand.
c. the sum of Ts and As in one strand would be greater than the sum of the Ts and As in the
other strand.
d. the sum of As and Cs in one strand would be less than the sum of the Ts and Gs in the
other strand.

Answer 61

a. the sum of Gs and Cs in one strand would be equal to the sum of the Gs and Cs in the
other strand.

Question 62

The sequence of DNA differs among individuals within a species. This is the basis for
a. mutation. c. base pairing.
b. protein structure. d. variations in phenotypes.

Answer 62

d. variations in phenotypes.

Question 63

The hereditary genetic material present in all living cells is
a. carbohydrate. c. DNA.
b. protein. d. RNA.

Answer 63

c. DNA.

Question 64

The order of the base pairs in a DNA molecule
a. differs from species to species.
b. is identical in all organisms.
c. is identical in organisms of the same species.
d. differs from cell to cell in a given organism.

Answer 64

a. differs from species to species.

Question 65

The significance of specific base pairing in DNA is that
a. it stabilizes the sugar molecule.
b. it provides a method for making exact copies of DNA.
c. it prevents errors in DNA replication.
d. protein copies can be made directly from the DNA

Answer 65

b. it provides a method for making exact copies of DNA.

Question 66

Once replication in a DNA molecule is complete, each new DNA molecule contains
a. one old strand and one new strand.
b. the paired old strands and the paired new strands.
c. new DNA polymerase.
d. a new sequence of nucleotides.

Answer 66

a. one old strand and one new strand.

Question 67

When a cell divides, it
a. breaks down its DNA.
b. deletes old genetic information.
c. copies information from neighboring cells.
d. copies its own genetic information.

Answer 67

d. copies its own genetic information.

Question 68

DNA replication
a. involves the copying of only the parts of a chromosome that encode protein.
b. occurs before mitosis in the cell cycle.
c. is constantly occurring in all the cells in your body.
d. converts the double helix to two single helices

Answer 68

b. occurs before mitosis in the cell cycle.

Question 69

Replication of DNA cannot begin until
a. phosphate bonds between nucleotides are broken.
b. hydrogen bonds between complementary bases are broken.
c. covalent bonds between sugar molecules are broken.
d. hydrogen bonds between nucleotides in one strand are broken

Answer 69

b. hydrogen bonds between complementary bases are broken.

Question 70

The adenine bases in a DNA molecule are radioactively labeled. The DNA is then placed in a solution
containing unlabeled nucleotides and the enzymes needed for DNA replication. The DNA molecule is
allowed to replicate twice, forming four new DNA molecules. You would find the radioactively labeled
adenine in
a. each of the eight strands. c. all but one strand.
b. two of the eight strands. d. six of the eight strands

Answer 70

b. two of the eight strands

Question 71

The polymerase chain reaction (PCR) is used to
a. produce many copies of a selected DNA sequence.
b. insert DNA from one organism into a new host.
c. screen for a particular gene.
d. deliver DNA products into a human patient.

Answer 71

a. produce many copies of a selected DNA sequence.

Question 72

The DNA primers used in polymerase chain reaction (PCR) are
a. identical to the entire base sequence of one strand of the DNA.
b. produced when a gene of interest is read by restriction enzymes.
c. attached to the gene of interest by polymerase.
d. complementary to DNA sequences at both ends of the DNA sequence of interest.

Answer 72

d. complementary to DNA sequences at both ends of the DNA sequence of interest.

Question 73

Mismatch errors are
a. almost always corrected by mutagens.
b. also called mutations.
c. almost always corrected by specialized proteins.
d. usually caused by mutated proteins

Answer 73

c. almost always corrected by specialized proteins.

Question 74

Which of the following must occur for a mismatch error to be repaired?
a. DNA repair proteins identify damaged DNA.
b. The sequence of nucleotides in the damaged DNA sequence guides the synthesis of the
correct DNA sequence.
c. DNA-eating enzymes within the nucleus destroy entire strands of damaged DNA.
d. The damaged DNA undergoes DNA replication one more time.

Answer 74

a. DNA repair proteins identify damaged DNA.

Question 75

Which of the following will NOT generally cause mutations?
a. chemicals c. viruses
b. radiation d. DNA replication

Answer 75

d. DNA replication

Question 76

A permanent change in the DNA base sequence due to an uncorrected mismatch error is called a(n)
a. mutation. c. repair protein.
b. replication. d. insertion.

Answer 76

a. mutation.

Question 77

The difference between the different alleles of a gene is
a. their DNA base sequences.
b. the way they are copied when the cell divides.
c. the type of lipid they are composed of.
d. they are not heritable.

Answer 77

a. their DNA base sequences

Question 78

A scientist uses polymerase chain reaction (PCR) to compare the sequence of a disease and
a healthy gene. The scientist finds that these two genes are identical except for one G in place
of a T at position 256 in the gene. This type of mutation is a(n)
a. deletion. c. silent mutation.
b. insertion. d. substitution mutation

Answer 78

d. substitution mutation

Question 79

Is a species that lacks DNA repair mechanisms likely to have more or fewer variations between
individuals than a species that possesses repair mechanisms?
a. fewer, because there are fewer ways to change the DNA
b. fewer, because the repair mechanisms introduce more variation into the DNA sequence
c. more, because more spontaneous mutations will go uncorrected
d. more, because without a repair mechanism, the cell’s DNA replication genes are
inactivated

Answer 79

c. more, because more spontaneous mutations will go uncorrected

Question 80

DNA fingerprinting is based on regions of DNA that are variable between individuals. Many of these
differences between individuals produce no change in phenotype. This type of mutation is a(n)
a. deletion. c. silent mutation.
b. insertion. d. substitution mutation.

Answer 80

c. silent mutation.

Question 81

Prokaryotes lack membrane-enclosed organelles and thus do not have nuclei. Therefore,
a. prokaryotes are unable to undergo transcription and translation.
b. prokaryotic cells do not need to undergo translation.
c. prokaryotic cells do not need to undergo transcription.
d. prokaryotic transcription and translation both take place in the cytoplasm

Answer 81

d. prokaryotic transcription and translation both take place in the cytoplasm

Question 82

A human gene put into a plant cell will
a. not produce a protein.
b. produce a plant protein.
c. produce the same protein produced in a human cell.
d. produce a hybrid protein consisting of both human and plant components.

Answer 82

c. produce the same protein produced in a human cell.

Question 83

DNA technology can be used with all organisms because they all
a. contain antibodies. c. share the same chemical DNA structure.
b. can contract the same diseases. d. contain the same genes

Answer 83

c. share the same chemical DNA structure.

Question 84

Bacteria and humans use the same DNA components, and both kinds of cells also perform transcription
and translation. Which of the following choices is a potentially significant outcome of this shared
mechanism?
a. Bacteria are able to transcribe and translate human DNA, and thus they potentially could
produce human proteins.
b. Bacteria are able to transcribe and translate human DNA, thus they could evolve into
humans.
c. Bacterial and human proteins are identical in amino acid sequence because the mechanism
for producing them is the same.
d. Bacterial and human DNA are identical in sequence because the method for producing
them is the same.

Answer 84

a. Bacteria are able to transcribe and translate human DNA, and thus they potentially could
produce human proteins.

Question 85

Protein coding genes specify the production of ________ as their immediate product.
a. rRNA c. DNA
b. tRNA d. mRNA

Answer 85

d. mRNA

Question 86

Which of the following best describes the function of genes?
a. They control the production of enzymes.
b. They control the production of structural proteins.
c. They control the production of all proteins.
d. They control the production of amino acids

Answer 86

c. They control the production of all proteins.

Question 87

Which of the following does NOT take place in the nucleus?
a. transcription c. replication
b. intron removal d. translation

Answer 87

d. translation

Question 88

The order of the bases in DNA determines the order of the
a. amino acids in DNA. c. amino acids in mRNA.
b. bases in a protein. d. bases in mRNA.

Answer 88

d. bases in mRNA.

Question 89

Some viruses produce an enzyme called reverse transcriptase. Based on your understanding of gene
expression, what should this enzyme do?
a. It produces RNA from a DNA template.
b. It produces DNA from an RNA template.
c. It produces proteins from an RNA template.
d. It produces RNA from a protein template.

Answer 89

b. It produces DNA from an RNA template.

Question 90

In bacteria, the antibiotic erythromycin prevents ribosomes from functioning. The most likely reason that
bacteria die from treatment with erythromycin is because the antibiotic
a. inhibits transcription.
b. inhibits translation.
c. causes the wrong bases to be added to the growing mRNA strand.
d. causes the wrong amino acids to be bound to the tRNA strands

Answer 90

b. inhibits translation.

Question 91

The key enzyme used during transcription is
a. RNA polymerase. c. rRNA.
b. DNA polymerase. d. terminase

Answer 91

a. RNA polymerase.

Question 92

As transcription begins, RNA polymerase binds to a segment of a gene called a(n)
a. promoter. c. start codon.
b. intron. d. anticodon

Answer 92

a. promoter.

Question 93

Which of the following is true of transcription?
a. It destroys the DNA template. c. Base pairing is unimportant.
b. The DNA molecule must unwind. d. The end result is a protein

Answer 93

b. The DNA molecule must unwind

Question 94

If a strand of DNA has the sequence CGTAA, the RNA made from this molecule will have the sequence
a. CGTAA. c. TAGCC.
b. GCUTT. d. GCAUU.

Answer 94

d. GCAUU.

Question 95

During transcription,
a. the DNA strands replicate, producing four mRNA molecules.
b. each strand in the DNA molecule directs the production of an mRNA molecule.
c. a template strand of DNA directs the production of an mRNA molecule.
d. a template strand of DNA directs the production of all of the tRNA molecules needed for
producing the gene’s protein product.

Answer 95

c. a template strand of DNA directs the production of an mRNA molecule.

Question 96

Following transcription, the
a. strands of DNA bond back to each other.
b. mRNA is digested.
c. DNA molecule is broken down.
d. ribosome is released from the tRNA molecule.

Answer 96

a. strands of DNA bond back to each other.

Question 97

A mutation occurs in the promoter of a protein-encoding gene. How might this mutation affect the
production of the protein encoded by the gene?
a. The mRNA made from this gene would exhibit the same mutation and, therefore, would
not fold or function properly.
b. The protein made from the promoter would have a different amino acid sequence and,
therefore, would not function properly.
c. The promoter might not be recognized by RNA polymerase, so the enzyme would be
unable to attach to the promoter and start transcription.
d. The start codon would be missing from the mRNA made from this gene, so the mRNA
could not be translated

Answer 97

c. The promoter might not be recognized by RNA polymerase, so the enzyme would be
unable to attach to the promoter and start transcription.

Question 98

The bases present in an RNA molecule are
a. C, T, A, and G. c. G, C ,U, and T.
b. U, A, C, and G. d. U, C, T, and A

Answer 98

b. U, A, C, and G.

Question 99

In bacteria, the antibiotic chloramphenicol prevents amino acids from bonding together. The most likely
reason that bacteria die from treatment with chloramphenicol is because the antibiotic
a. inhibits transcription.
b. inhibits translation.
c. causes the wrong bases to be added to the growing mRNA strand.
d. causes the wrong amino acids to be bound to the tRNA strands.

Answer 99

b. inhibits translation.

Question 100

Which molecules are involved in translation?
a. DNA and RNA c. mRNA, tRNA, and rRNA
b. mDNA, tDNA, and rDNA d. proteins, amino acids, and DNA

Answer 100

c. mRNA, tRNA, and rRNA

Question 101

Which RNA molecule brings new amino acids to the growing protein chain in translation?
a. mRNA c. rRNA
b. tRNA d. dRNA

Answer 101

b. tRNA

Question 102

The importance of tRNA is that it
a. carries a specific amino acid to the mRNA.
b. reads the DNA molecule.
c. contains codons that specify amino acids.
d. is important in the construction of ribosomes.

Answer 102

a. carries a specific amino acid to the mRNA.

Question 103

Which of the following is true of rRNA?
a. It is made up of base pairs. c. It is not translated.
b. It carries amino acids. d. It helps transcribe DNA.

Answer 103

c. It is not translated.

Question 104

During translation,
a. many mRNA molecules work with one tRNA molecule and one rRNA molecule to
produce a protein.
b. one tRNA molecule works with paired mRNA molecules and many rRNA molecules to
produce a protein.
c. strings of bonded tRNA molecules work with one mRNA molecule and one rRNA
molecule to produce a protein.
d. one mRNA molecule works with several rRNA molecules and many tRNA molecules to
produce a protein.

Answer 104

d. one mRNA molecule works with several rRNA molecules and many tRNA molecules to
produce a protein.

Question 105

Consider a build-at-home bookshelf that comes with instructions and various pieces of wood as an
analogy for translation. In this analogy, what would best match the job of the ribosome?
a. the instructions c. the pieces of wood
b. the person building the bookshelf d. the bookshelf

Answer 105

b. the person building the bookshelf

Question 106

In bacteria, the antibiotic tetracycline blocks the site where tRNA molecules enter the ribosome. The most
likely reason that bacteria die from treatment with tetracycline is because the antibiotic
a. inhibits the cell from producing the mRNA.
b. causes the tRNA molecules to randomly arrange into proteins that do not function.
c. causes tRNA rather than mRNA to be made into proteins.
d. prevents the bacteria from assembling essential proteins.

Answer 106

d. prevents the bacteria from assembling essential proteins.

Question 107

Each set of three bases in an mRNA molecule codes for one of 20 specific
a. rRNA molecules. c. amino acids.
b. nucleotides. d. proteins.

Answer 107

c. amino acids.