Full file at
CHAPTER 2 Genetics
MULTIPLE CHOICE
1.Chromosomes are
a. / small linear bodies.b. / contained in cells.
c. / replicated during cell division.
d. / all of the above
ANS:DDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
2.A cross between true-breeding plants bearing yellow seeds produces offspring bearing
a. / yellow seeds.b. / 1/2 yellow and 1/2 green seeds.
c. / untrue-breeding seeds.
d. / none of the above
ANS:ADIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
3.Cross-breeding the offspring of green and yellow peas led to ______in the second generation.
a. / only green individuals surviving the first days of lifeb. / a 3:1 ratio of yellow to green offspring
c. / yellowish-green individuals
d. / half the offspring being green and the other half yellow
ANS:BDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
4.Gametes
a. / are not involved in the transmission of genes.b. / are the sex cells, or eggs and sperm.
c. / do not differ between male and female animals.
d. / were discovered by Darwin.
ANS:BDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
5.Mendel’s first law (of segregation) states that
a. / characteristics from the parents blend together to produce intermediate offspring.b. / characteristics from the parents do not blend together in offspring.
c. / paternally and maternally derived characteristics segregate into gametes during meiosis.
d. / b and c only
ANS:DDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
6.Mendel’s second law (of independent assortment) states that
a. / the probability of inheriting one trait does not affect the probability of inheriting another trait.b. / the probability of inheriting one trait does affect the probability of inheriting another trait.
c. / the probability of inheriting one trait is never equal to the probability of inheriting another trait.
d. / traits on the same chromosome cannot assort into gametes.
ANS:ADIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
7.Mendel’s second law (of independent assortment) states that
a. / eggs and sperm are formed independently of one another.b. / transmission includes both blending and particulate inheritance.
c. / particles inherited from the mother and the father are equally likely
to be transmitted to offspring.
d. / b and c only
ANS:CDIF:3
TOP:Cell Division and the Role of Chromosomes in Inheritance
8.Chromosomes are contained in
a. / the gametes.b. / the nucleus of the cell.
c. / every cell of the body.
d. / all of the above
ANS:DDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
9.Homologous chromosomes
a. / come in pairs.b. / are similar in size and staining pattern.
c. / are found in primates.
d. / all of the above
ANS:DDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
10.Mitosis
a. / involves duplication of a set of chromosomes.b. / results in a daughter cell that has an exact copy of the chromosomes of its parent.
c. / results in cells that contain the same chromosomes that were present when the egg and sperm united.
d. / all of the above
ANS:DDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
11.Reduction of chromosome number occurs during
a. / recombination.b. / meiosis.
c. / somatic cell formation.
d. / linked genes.
ANS:BDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
12.A pea plant with only green seeds is
a. / homozygous recessive.b. / always tall.
c. / an example of blending inheritance.
d. / b and c only
ANS:ADIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
13.If you have two parents with the genotype Aa, what is the chance that they will have an offspring with the genotype AA?
a. / 1/8b. / 1/2
c. / 1/4
d. / 1/16
ANS:CDIF:3
TOP:Cell Division and the Role of Chromosomes in Inheritance
14.The possible genotype of a pea plant with yellow seeds is
a. / AA.b. / aa.
c. / Aa.
d. / a and c only
ANS:DDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
15.In diploid organisms
a. / chromosomes occur in homologous pairs.b. / chromosomes occur in homologous triplets.
c. / meiosis produces haploid gametes.
d. / a and c only
ANS:DDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
16.In mitosis
a. / a haploid cell divides into two diploid cells.b. / a diploid cell divides into two haploid cells.
c. / a haploid cell divides into two diploid cells.
d. / a diploid cell divides into two diploid cells.
ANS:DDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
17.Which of the following is (are) true of mitosis?
a. / Mitosis produces identical daughter cells.b. / Mitosis produces nonidentical daughter cells.
c. / Mitosis produces cells with different chromosomes.
d. / b and c only
ANS:ADIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
18.In meiosis
a. / haploid cells are produced from a single diploid cell.b. / haploid cells are produced from two diploid cells.
c. / diploid cells are produced from a single diploid cell.
d. / diploid cells are produced from two haploid cells.
ANS:ADIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
19.Which of the following is (are) true of meiosis?
a. / Daughter cells contain one chromosome from each homologous pair.b. / Daughter cells contain both chromosomes from each homologous pair.
c. / Meiosis produces sex cells.
d. / a and c only
ANS:DDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
20.Gametes
a. / contain one of each pair of homologous chromosomes.b. / are responsible for normal body growth of organisms.
c. / can be eggs or sperm.
d. / a and c only
ANS:DDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
21.Which sequence is correct?
a. / diploid individual haploidgamete diploid zygote body growthb. / diploid individual meiosis fertilization mitosis
c. / diploid individual mitosis zygote formation diploid individual
d. / all of the above
ANS:DDIF:3
TOP:Cell Division and the Role of Chromosomes in Inheritance
22.A zygote is
a. / a single cell.b. / a union of two gametes.
c. / a cell that may undergo mitosis.
d. / all of the above
ANS:DDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
23.An allele
a. / is a form of a gene.b. / contributes to an individual phenotype.
c. / contributes to an individual genotype.
d. / all of the above
ANS:DDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
24.The genotype of an individual refers to
a. / its visible characteristics.b. / the number of chromosomes in its sex cells.
c. / the number of chromosomes in its body cells.
d. / none of the above
ANS:DDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
25.The phenotype of an individual refers to
a. / its visible characteristics.b. / the number of homologous pairs of chromosomes.
c. / the number of chromosomes in its body cells.
d. / the number of chromosomes in its sex cells.
ANS:ADIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
26.An individual with two identical alleles at a locus is
a. / an independent phenotype.b. / a homozygote.
c. / a heterozygote.
d. / dominant.
ANS:BDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
27.A heterozygote is an individual with
a. / the same paternal and maternal allele at a particular locus.b. / a different paternal and maternal allele at a particular locus.
c. / a recessive allele.
d. / a and c only
ANS:BDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
28.True-breeding plants bearing yellow seeds have what genotype?
a. / aab. / aA
c. / Aa
d. / AA
ANS:DDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
29.When Mendel crossed true-breeding plants bearing yellow seeds with true-breeding plants bearing green seeds, what was the phenotypic ratio among the F1offspring?
a. / all aa individualsb. / all AA individuals
c. / 1/2 yellow and 1/2 green individuals
d. / all yellow individuals
ANS:DDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
30.True-breeding plants bearing green seeds have what genotype?
a. / aab. / aA
c. / Aa
d. / AA
ANS:ADIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
31.When a true-breeding plant bearing yellow seeds produces gametes, what alleles are represented among those gametes?
a. / only A allelesb. / only a alleles
c. / both a and A alleles, in equal frequencies
d. / both a and A alleles, but mostly A alleles
ANS:ADIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
32.When Mendel crossed true-breeding plants bearing yellow seeds with true-breeding plants bearing green seeds, what was the genotypic ratio among the F1offspring?
a. / all aa individualsb. / all AA individuals
c. / all Aa individuals
d. / all green individuals
ANS:CDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
33.When Mendel crossed individuals from the F1generation with each other, what was the genotypic ratio among the offspring?
a. / all Aa or aAb. / 25% aa, 50% Aa/aA, and 25% AA
c. / all AA or aa
d. / 33.3% aa, 33.3% Aa/aA, and 33.3% AA
ANS:BDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
34.When Mendel crossed individuals from the F1generation with each other, what was the phenotypic ratio among the offspring?
a. / all yellowb. / 1/2 green and 1/2 yellow
c. / 3/4 yellow and 1/4 green
d. / 3/4 green and 1/4 yellow
ANS:CDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
35.The probability of an offspring getting two A alleles, one from the father and one from the mother, is
a. / 50%.b. / 25%.
c. / 12.5%.
d. / 12.5%.
ANS:BDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
36.When Mendel crossed heterozygote pea plants for two different traits, he recorded a phenotypic ratio of
a. / 1:2:1.b. / 4:8:4.
c. / 9:3:3:1.
d. / 12:4.
ANS:CDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
37.Recombination and crossing-over are very important in the genetic process because they produce
a. / variation.b. / a new somatic cell.
c. / DNA.
d. / linked chromosomes.
ANS:ADIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
38.What is the probability that an Aa individual will produce a gamete with an A allele?
a. / 100%b. / 75%
c. / 50%
d. / 25%
ANS:CDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
39.Consider a cross between tall and short plants in which all of the offspring are tall. This suggests that
a. / the allele for tall is recessive.b. / the allele for tall is dominant.
c. / the alleles for tall and short are codominant.
d. / none of the above
ANS:BDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
40.What is the probability of a heterozygote for seed coat and color having an aB gamete?
a. / 100%b. / 50%
c. / 25%
d. / 0%
ANS:CDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
41.Mendel crossed AABB with aabb individuals, where B = smooth, b = wrinkled, A = yellow, and a = green. What was the genotypic ratio of the F1 generation?
a. / all AAbbb. / 1/2 AAbb and 1/2 aaBB
c. / all AaBb
d. / all AABB
ANS:CDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
42.Imagine a cross between AA and Aa individuals. What is the genotypic ratio among the offspring?
a. / 1/2 AA and 1/2 aab. / 1/2 Aa and 1/2 aa
c. / 1/2 AA and 1/2 Aa
d. / all AA
ANS:CDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
43.Under which circumstance does Mendel’s law of independent assortment hold?
a. / only when traits are tightly linked (close together) on the same chromosomeb. / only when traits are on different chromosomes
c. / only when there is crossing over
d. / a and c only
ANS:BDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
44.Independent assortment states that
a. / the fact that a gamete has an A rather than an a allele does not influence the probability that it will have a B rather than a b allele.b. / alleles at different loci do not influence each other as they assort into gametes.
c. / dominant alleles act independently of recessive alleles.
d. / a and b only
ANS:DDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
45.Which of the following is (are) true of chromosomes?
a. / Hereditary material is contained in the chromosomes.b. / Chromosomes come in pairs.
c. / One chromosome from each homologous pair is passed on to daughter cells during meiosis.
d. / all of the above
ANS:DDIF:1
TOP:Cell Division and the Role of Chromosomes in Inheritance
46.Imagine two loci on one chromosome. At one locus, the genotype is Aa and at the other locus, the genotype is Bb. After meiosis, what are all of the possible genotypes of the gametes?
a. / AB and ab gametesb. / all AB gametes
c. / AB, ab, Ab, and aB gametes
d. / Ab and aB gametes
ANS:CDIF:3
TOP:Cell Division and the Role of Chromosomes in Inheritance
47.Crossing over
a. / occurs when homologous pairs of chromosomes exchange material.b. / increases genetic combinations.
c. / can occur between loci on the same chromosome.
d. / all of the above
ANS:DDIF:3
TOP:Cell Division and the Role of Chromosomes in Inheritance
48.When two loci are very close together on a chromosome
a. / they are linked.b. / a crossing-over event between them is less likely than when two loci are far apart.
c. / they can blend into a single gene.
d. / a and b only
ANS:DDIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
49.Molecular genetics
a. / produces new discoveries in medicine and agriculture.b. / links biology to chemistry and physics.
c. / provides data for reconstructing the evolutionary history of species.
d. / all of the above
ANS:DDIF:1TOP:Molecular Genetics
50.Two traits are less likely to assort independently if
a. / the loci are on the same as opposed to different chromosomes.b. / the loci are far apart as opposed to close together on the same chromosome.
c. / they are heterozygous.
d. / a and b only
ANS:ADIF:2
TOP:Cell Division and the Role of Chromosomes in Inheritance
51.Modern molecular genetics
a. / resulted from the discovery of the structure of DNA.b. / links biology to chemistry and physics.
c. / provides important data for reconstructing evolutionary history.
d. / all of the above
ANS:DDIF:1TOP:Molecular Genetics
52.Analysis of DNA sequences tells us
a. / that humans and chimpanzees share a more recent common ancestor than either shares with gorillas.b. / that the last common ancestor of chimpanzees and human lived between 5 and 7 mya.
c. / when the first modern humans left Africa and where they went.
d. / all of the above
ANS:DDIF:2TOP:Molecular Genetics
53.DNA is a complex molecule with many alternative forms that are equally stable chemically, which allows
a. / the double helix to form.b. / independent evolution.
c. / the message that DNA carries to be transmitted faithfully.
d. / continuous variation.
ANS:CDIF:2TOP:Molecular Genetics
54.The structure of DNA is that of
a. / a series of intertwining chromosomes.b. / a double-stranded molecule, consisting of four bases.
c. / a series of nucleotides: adenine, guanine, thymine, and cytosine.
d. / b and c only
ANS:DDIF:2TOP:Molecular Genetics
55.Are any of the following statements true?
a. / DNA has a nonrepeating four-base structure.b. / DNA is contained in chromosomes.
c. / DNA stands for determining nuclear acid.
d. / DNA does not tell us why heredity leads to the patterns Mendel described in pea plants.
ANS:BDIF:1TOP:Molecular Genetics
56.Exact replication of DNA is possible due to
a. / the low number of possible nucleotides.b. / base-pair complementarity.
c. / the sequence of nucleotides along the DNA, which is always the same.
d. / a and c only
ANS:BDIF:1TOP:Molecular Genetics
57.Sickle-cell anemia
a. / is common among people of West Africa.b. / is caused by a single amino acid change in the hemoglobin molecule.
c. / results when hemoglobin molecules do not fold correctly, reducing their ability to bind to oxygen.
d. / all of the above
ANS:DDIF:2TOP:Molecular Genetics
58.Unlike a eukaryote, a prokaryote
a. / does not have a cell nucleus.b. / has uninterrupted DNA sequences that code for proteins.
c. / lacks chromosomes.
d. / all of the above
ANS:DDIF:3TOP:Molecular Genetics
59.Alternative splicing
a. / involves the snipping out of intron-based parts of mRNA.b. / means that some entrons are not included when the mRNA is spliced back together.
c. / allows the same DNA sequence to code for more than one protein.
d. / all of the above
ANS:DDIF:3TOP:Molecular Genetics
60.Some biologists hypothesize that introns are maintained in eukaryotes because their population sizes are much smaller than in prokaryotes. ______is the random, nonadaptive evolutionary process that explains this phenomenon.
a. / Genetic driftb. / Natural selection
c. / Protein synthesis
d. / Transcription
ANS:ADIF:3TOP:Molecular Genetics
61.The mRNA codon for the amino acid TGG is ______, and its tRNA anticodon is ______.
a. / AGG; UCCb. / GGT; CCA
c. / GTG; CAC
d. / UGG; ACC
ANS:DDIF:2TOP:Molecular Genetics
62.Within DNA are properties that specify
a. / the linear sequence of amino acids in a protein (primary structure).b. / the way in which the protein folds up (tertiary structure).
c. / the function of the protein.
d. / all of the above
ANS:DDIF:2TOP:Molecular Genetics
63.Which of the following is (are) true of DNA transcription/translation?
a. / A codon corresponds to an amino acid.b. / A DNA sequence codes for a protein.
c. / A protein consists of a series of codons.
d. / a and b only
ANS:DDIF:1TOP:Molecular Genetics
64.Because there are 64 possible codons and only 20 amino acids a. many mutations have no effect on phenotype.
a. / every mutation has some effect on phenotype. Genetics / 155b. / each tRNA molecule contains two extra amino acids.
c. / each tRNA molecule contains two extra codons.
ANS:ADIF:2TOP:Molecular Genetics
65.Which of the following sequences is accurate for transcription and translation?
a. / DNAtRNA mRNA proteinb. / DNA mRNAprotein
c. / Protein tRNA DNA
d. / Protein tRNA DNA
ANS:BDIF:2TOP:Molecular Genetics
66.As DNA codes for proteins it can be interrupted by noncoding sequences called
a. / organelles.b. / proteins.
c. / introns.
d. / synthetases.
ANS:CDIF:1TOP:Molecular Genetics
67.The presence of repressors and activators in regulatory genes means that there is ______of gene expression.
a. / translationb. / combinational control
c. / a biochemical pathway
d. / primary structure
ANS:BDIF:2TOP:Molecular Genetics
68.The organelles that splice the mRNA in eukaryotes after the introns have been snipped out are called
a. / splitsomes.b. / mergesomes.
c. / splicesomes.
d. / unitesomes.
ANS:CDIF:1TOP:Molecular Genetics