A human cell containing 22 autosomes and a Y chromosome is
A) a sperm
B) an egg
C) a zygote
D) a somatic cell of a male
A
Homologous chromosomes move toward opposite poles of a dividing cell during
A) mitosis
B) meiosis I
C) meiosis II
D) fertilization
B
Meiosis II is similar to mitosis in that
A) sister chromatids separate during anaphase
B) DNA replicated before the division
C) the daughter cells are diploid
D) homologous chromosomes synapse
A
If the DNA content of a diploid cell in the G1 phase of a cell cycle is x, then the DNA content of the same cell at metaphase of meiosis I would be
A) 0.25x
B) 0.5x
C) x
D) 2x
D
If the DNA content of a diploid cell in the G1 phase of a cell cycle is x, then the DNA content of the same cells at metaphase of meiosis II would be
A) 0.25x
B) 0.5x
C) x
D) 2x
C
In his work with pneumonia-causing bacteria and mice, Griffith found that
A) the protein coat from pathogenic cells was able to transform nonpathogenic cells
B) heat-killed pathogenic cells caused pneumonia
C) some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic
D) the polysaccharide coat of bacteria caused pneumonia
C
What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized?
A) the origins of replication occur only at the 5' end
B) helicases and single-strand binding proteins work at the 5' end
C) DNA polymerase can join new nucleotides only to the 3' end of a pre-existing strand
D) DNA ligase works only in the 3' → 5' direction
C
In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules?
A) A = G
B) A + G = C + T
C) A + T = G + C
D) A = C
B
The elongation of the leading strand during DNA synthesis
A) progresses away from the replication fork
B) occurs in the 3' → 5' direction
C) does not require a template strand
D) depends on the action of DNA polymerase
D
In a nucleosome, the DNA is wrapped around
A) histones
B) ribosomes
C) plymerase molecules
D) a thymine dimer
A
E. Coli cells grown on 15N medium are transferred to 14N medium and allowed to grow for more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged. What density distribution of DNA would you expect in this experiment?
A) one high-density and one low-density band
B) one intermediate-density band
C) one high-density and one intermediate-density band
D) one low-density band and one intermediate-density band
D
A biochemist isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. When she adds some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture?
A) DNA polymerase
B) DNA ligase
C) Okazaki fragments
D) primase
B
The spontaneous loss of amino groups form adenine in DNA results in hypoxanthine, and uncommon base, opposite thymine.What combination of proteins could repair such damage?
A) nuclease, DNA polymerase, DNA ligase
B) telomerase, primase, DNA polymerase
C) telomerase, helicase, single-stranded binding protein
D) DNA ligase, replication fork proteins, adenylyl cyclase
A
The human genome is minimally contained in which of the
following?
A) every human cell
B) each human chromosome
C) the entire DNA of a single human
D) the entire human
population
E) each human gene
A
Which of the following defines a genome?
A) representation of a
complete set of a cell's polypeptides
B) the complete set of an
organism's polypeptides
C) the complete set of a species'
polypeptides
D) a karyotype
E) the complete set of an
organism's genes
E
If a horticulturist breeding gardenias succeeds in having a single
plant with a particularly desirable set of traits, which of the
following would be her most probable and efficient route to
establishing a line of such plants?
A) Backtrack through
her previous experiments to obtain another plant with the same
traits.
B) Breed this plant with another plant with much weaker
traits.
C) Clone the plant asexually to produce an identical
one.
D) Force the plant to self-pollinate to obtain an
identical one.
E) Add nitrogen to the soil of the offspring of
this plant so the desired traits continue.
C
Which of the following is a true statement about sexual vs. asexual
reproduction?
A) Asexual reproduction, but not sexual
reproduction, is characteristic of plants and fungi.
B) In
sexual reproduction, individuals transmit 50% of their genes to each
of their offspring.
C) In asexual reproduction, offspring are
produced by fertilization without meiosis.
D) Sexual
reproduction requires that parents be diploid.
E) Asexual
reproduction produces only haploid offspring.
B
There is a group of invertebrate animals called rotifers, among which
a particular group of species reproduces, as far as is known, only
asexually. These rotifers, however, have survived a long evolutionary
history without evidence of having been overcome by excessive
mutations.
60) Since the rotifers develop from eggs, but
asexually, what can you predict?
A) The eggs and the zygotes
are all haploid.
B) The animals are all hermaphrodites.
C) While asexual, both males and females are found in nature.
D) All males can produce eggs.
E) No males can be found.
E
How is natural selection related to sexual reproduction as opposed to
asexual reproduction?
A) Sexual reproduction results in many new
gene combinations, some of which will lead to differential
reproduction.
B) Sexual reproduction results in the most
appropriate and healthiest balance of two sexes in the population.
C) Sexual reproduction results in the greatest number of new
mutations.
D) Sexual reproduction allows the greatest number of
offspring to be produced.
E) Sexual reproduction utilizes far
less energy than asexual reproduction.
A
In the human species, all somatic cells have 46 chromosomes. Which of
the following can also be true?
A) A plant species (privet
shrubs) has 46 chromosomes per cell.
B) Some adult humans have
69 chromosomes per cell.
C) Some adult humans have 23
chromosomes per cell.
D) A certain fungal species has only one
chromosome per cell.
E) A certain bacterial species has 23 chromosomes.
A
The human X and Y chromosomes
A) are both present in every
somatic cell of males and females alike.
B) are of approximately
equal size and number of genes.
C) are almost entirely
homologous, despite their different names.
D) include genes that
determine an individual's sex.
E) include only genes that govern
sex determination.
D
Which of the following is true of a species that has a chromosome
number of 2n = 16?
A) The species is diploid with 32
chromosomes per cell.
B) The species has 16 sets of chromosomes
per cell.
C) Each cell has eight homologous pairs.
D)
During the S phase of the cell cycle there will be 32 separate
chromosomes.
E) A gamete from this species has four chromosomes.
C
The karyotype of one species of primate has 48 chromosomes. In a
particular female, cell division goes awry and she produces one of her
eggs with an extra chromosome (25). The most probable source of this
error would be a mistake in which of the following?
A) mitosis
in her ovary
B) metaphase I of one meiotic event
C)
telophase II of one meiotic event
D) telophase I of one meiotic
event
E) either anaphase I or II
E
A triploid cell contains three sets of chromosomes. If a cell of a
usually diploid species with 42 chromosomes per cell is triploid, this
cell would be expected to have which of the following?
A) 63
chromosomes in 31 1/2 pairs
B) 63 chromosomes in 21 sets of 3
C) 63 chromosomes, each with three chromatids
D) 21
chromosome pairs and 21 unique chromosomes
B
Independent assortment of chromosomes is a result of
A)
the random and independent way in which each pair of homologous
chromosomes lines up at the metaphase plate during meiosis I.
B) the random nature of the fertilization of ova by sperm.
C) the random distribution of the sister chromatids to the two
daughter cells during anaphase II.
D) the relatively small
degree of homology shared by the X and Y chromosomes.
E) the
random and independent way in which each pair of homologous
chromosomes lines up at the metaphase plate during meiosis I, the
random nature of the fertilization of ova by sperm, the random
distribution of the sister chromatids to the two daughter cells during
anaphase II, and the relatively small degree of homology shared by the
X and Y chromosomes.
A
Eukaryotic sexual life cycles show tremendous variation. Of the
following elements, which do all sexual life cycles have in
common?
I. Alternation of generations
II. Meiosis
III. Fertilization
IV. Gametes
V. Spores
A) I, IV, and V
B) I, II, and IV
C) II, III, and IV
D) II, IV, and V
E) I, II, III, IV, and V
C
Referring to a plant's sexual life cycle, which of the following
terms describes the process that leads directly to the formation of
gametes?
A) sporophyte meiosis
B) gametophyte mitosis
C) gametophyte meiosis
D) sporophyte mitosis
E)
alternation of generations
B
Which of the life cycles is typical for animals?
A) I only
B) II only
C) III only
D) I and II
E) I and III
A
Which of the life cycles is typical for plants and some algae?
A) I only
B) II only
C) III only
D) I and II
E) I and III
C
Which of the life cycles is typical for most fungi and some protists?
A) I only
B) II only
C) III only
D) I and II
E) I and III
B
Which life cycle stage is found in plants but not animals?
A)
gamete
B) zygote
C) multicellular diploid
D)
multicellular haploid
E) unicellular diploid
D
At which stage of mitosis are chromosomes usually photographed in the
preparation of a karyotype?
A) prophase
B) metaphase
C) anaphase
D) telophase
E) interphase
B
A given organism has 46 chromosomes in its karyotype. We can
therefore conclude which of the following?
A) It must be human.
B) It must be a primate.
C) It must be an animal.
D)
It must be sexually reproducing.
E) Its gametes must have 23 chromosomes.
E
When Thomas Hunt Morgan crossed his red-eyed F₁ generation flies to
each other, the F₂ generation included both red- and white-eyed flies.
Remarkably, all the white-eyed flies were male. What was the
explanation for this result?
A) The gene involved is on
the Y chromosome.
B) The gene involved is on the X chromosome.
C) The gene involved is on an autosome, but only in males.
D) Other male-specific factors influence eye color in flies.
E) Other female-specific factors influence eye color in flies.
B
Thomas Hunt Morgan's choice of Drosophila melanogaster has been
proven to be useful even today. Which of the following has/have
continued to make it a most useful species?
I. its four
pairs of chromosomes
II. a very large number of visible as well
as biochemically mutant phenotypes
III. easy and inexpensive
maintenance
IV. short generation time and large number of
offspring
A) I and IV only
B) II and III only
C) I, II, and III only
D) II, III, and IV only
E)
I, II, III, IV, and V
E
The centimorgan (cM) is a unit named in honor of Thomas Hunt Morgan.
To what is it equal?
A) the physical distance between two linked
genes
B) 1% frequency of recombination between two genes
C) 1 nanometer of distance between two genes
D) the
distance between a pair of homologous chromosomes
E) the
recombination frequency between two genes assorting independently
B
Sturtevant provided genetic evidence for the existence of four pairs
of chromosomes in Drosophila in which of these ways?
A)
There are four major functional classes of genes in Drosophila.
B) Drosophila genes cluster into four distinct groups of linked
genes.
C) The overall number of genes in Drosophila is a
multiple of four.
D) The entire Drosophila genome has
approximately 400 map units.
E) Drosophila genes have, on
average, four different alleles.
B
Which of the following is the meaning of the chromosome theory of
inheritance as expressed in the early 20th century?
A)
Individuals inherit particular chromosomes attached to genes.
B) Mendelian genes are at specific loci on the chromosome and in
turn segregate during meiosis.
C) Homologous chromosomes give
rise to some genes and crossover chromosomes to other genes.
D)
No more than a single pair of chromosomes can be found in a healthy
normal cell.
E) Natural selection acts on certain chromosome
arrays rather than on genes.
B
A gene is considered to be non-Mendelian in its inheritance pattern
if it seems to "violate" Mendel's laws. Which of the
following would be considered Mendelian?
A) a gene whose
expression varies depending on the gender of the transmitting parent
B) a gene derived solely from maternal inheritance
C) a
gene transmitted via the cytoplasm or cytoplasmic structures
D) a
gene transmitted to males from the maternal line and from fathers to
daughters
E) a gene transmitted by a virus to egg-producing cells
D
Which of the following produces a Mendelian pattern of
inheritance?
A) genomic imprinting
B) a mitochondrial gene
mutation
C) a chloroplast gene mutation
D) viral genomes
that inhabit egg cytoplasm
E) a trait acted upon by many genes
E
Correns described that the inheritance of variegated color on the
leaves of certain plants was determined by the maternal parent only.
What phenomenon does this describe?
A) mitochondrial inheritance
B) chloroplast inheritance
C) genomic imprinting
D)
infectious inheritance
E) sex-linkage
B
Males are more often affected by sex-linked traits than females
because
A) male hormones such as testosterone often
alter the effects of mutations on the X chromosome.
B) female
hormones such as estrogen often compensate for the effects of
mutations on the X chromosome.
C) X chromosomes in males
generally have more mutations than X chromosomes in females.
D)
males are hemizygous for the X chromosome.
E) mutations on the
Y chromosome often worsen the effects of X-linked mutations.
D
SRY is best described in which of the following ways?
A) a gene present on the X chromosome that triggers female
development
B) an autosomal gene that is required for the
expression of genes on the Y chromosome
C) a gene region present
on the Y chromosome that triggers male development
D) an
autosomal gene that is required for the expression of genes on the X
chromosome
E) a gene required for development, and males or
females lacking the gene do not survive past early childhood
C
Red-green color blindness is a sex-linked recessive trait in humans.
Two people with normal color vision have a color-blind son. What are
the genotypes of the parents?
A) XcXc and XcY
B) XcXc and
XCY
C) XCXC and XcY
D) XCXC and XCY
E) XCXc and XCY
E
Cinnabar eyes is a sex-linked recessive characteristic in fruit
flies. If a female having cinnabar eyes is crossed with a wild-type
male, what percentage of the F₁ males will have cinnabar eyes?
A) 0%
B) 25%
C) 50%
D) 75%
E) 100%
E
Calico cats are female because
A) the males die during embryonic
development.
B) a male inherits only one of the two X-linked
genes controlling hair color.
C) the Y chromosome has a gene
blocking orange coloration.
D) only females can have Barr
bodies.
E) multiple crossovers on the Y chromosome prevent
orange pigment production.
B
Sex determination in mammals is due to the SRY region of the Y
chromosome. An abnormality of this region could allow which of the
following to have a male phenotype?
A) Turner syndrome, 45, X
B) translocation of SRY to an autosome of a 46, XX individual
C) a person with an extra X chromosome
D) a person with
one normal and one shortened (deleted) X
E) Down syndrome, 46, XX
B
In humans, clear gender differentiation occurs, not at fertilization,
but after the second month of gestation. What is the first event of
this differentiation?
A) formation of testosterone in male
embryos
B) formation of estrogens in female embryos
C)
anatomical differentiation of a penis in male embryos
D)
activation of SRY in male embryos and masculinization of the gonads
E) activation of SRY in females and feminization of the gonads
D
Which of the following differentiates between independent assortment
and segregation?
A) The law of independent assortment requires
describing two or more genes relative to one another.
B) The law
of segregation requires describing two or more genes relative to one
another.
C) The law of segregation requires having two or more
generations to describe.
D) The law of independent assortment is
accounted for by observations of prophase I.
E) The law of
segregation is accounted for by anaphase of mitosis.
A
Mendel's observation of the segregation of alleles in gamete
formation has its basis in which of the following phases of cell
division?
A) prophase I of meiosis
B) anaphase II of
meiosis
C) metaphase I of meiosis
D) anaphase I of meiosis
E) anaphase of mitosis
D
At what point in cell division is a chromosome lost so that, after
fertilization with a normal gamete, the result is an embryo with 45,
X?
I. an error in anaphase I
II. an error in
anaphase II
III. an error of the first postfertilization
mitosis
IV. an error in pairing
A) I or II only
B) II or IV only
C) III or IV only
D) I, II, or III
only
E) I, II, III, or IV
E
Polytene chromosomes of Drosophila salivary glands each consist of
multiple identical DNA strands that are aligned in parallel arrays.
How could these arise?
A) replication followed by mitosis
B) replication without separation
C) meiosis followed by
mitosis
D) fertilization by multiple sperm
E) special
association with histone proteins
B
In trying to determine whether DNA or protein is the genetic
material, Hershey and Chase made use of which of the following facts?
A) DNA contains sulfur, whereas protein does not.
B) DNA
contains phosphorus, whereas protein does not.
C) DNA contains
nitrogen, whereas protein does not.
D) DNA contains purines,
whereas protein includes pyrimidines.
E) RNA includes ribose,
whereas DNA includes deoxyribose sugars.
B
Which of the following investigators was/were responsible for the
following discovery?
In DNA from any species, the amount of
adenine equals the amount of thymine, and the amount of guanine equals
the amount of cytosine.
A) Frederick Griffith
B) Alfred
Hershey and Martha Chase
C) Oswald Avery, Maclyn McCarty, and
Colin MacLeod
D) Erwin Chargaff
E) Matthew Meselson and
Franklin Stahl
D
Cytosine makes up 42% of the nucleotides in a sample of DNA from an
organism. Approximately what percentage of the nucleotides in this
sample will be thymine?
A) 8%
B) 16%
C) 31%
D)
42%
E) It cannot be determined from the information provided.
A
What is meant by the description "antiparallel" regarding
the strands that make up DNA?
A) The twisting nature of DNA
creates nonparallel strands.
B) The 5' to 3' direction of one
strand runs counter to the 5' to 3' direction of the other strand.
C) Base pairings create unequal spacing between the two DNA
strands.
D) One strand is positively charged and the other is
negatively charged.
E) One strand contains only purines and the
other contains only pyrimidines.
B
Use the following list of choices for the following question
I.
helicase
II. DNA polymerase III
III. ligase
IV. DNA
polymerase I
V. primase
31) Which of the enzymes
removes the RNA nucleotides from the primer and adds equivalent DNA
nucleotides to the 3' end of Okazaki fragments?
A) I
B)
II
C) III
D) IV
E) V
D
In E. coli, there is a mutation in a gene called dnaB that alters the
helicase that normally acts at the origin. Which of the following
would you expect as a result of this mutation?
A) No
proofreading will occur.
B) No replication fork will be formed.
C) The DNA will supercoil.
D) Replication will occur via
RNA polymerase alone.
E) Replication will require a DNA template
from another source.
B
What is a syndrome?
A) a characteristic facial appearance
B) a group of traits, all of which must be present if an
aneuploidy is to be diagnosed
C) a group of traits typically
found in conjunction with a particular chromosomal aberration or gene
mutation
D) a characteristic trait usually given the
discoverer's name
E) a characteristic that only appears in
conjunction with one specific aneuploidy
C
If nondisjunction occurs in meiosis II during gametogenesis, what
will be the result at the completion of meiosis?
A) All the
gametes will be diploid.
B) Half of the gametes will be n + 1,
and half will be n - 1.
C) 1/4 of the gametes will be n + 1, 1/4
will be n - 1, and 1/2 will be n.
D) There will be three extra
gametes.
E) Two of the four gametes will be haploid, and two
will be diploid.
C
After telophase I of meiosis, the chromosomal makeup of each daughter
cell is
A) diploid, and the chromosomes are each composed of a
single chromatid.
B) diploid, and the chromosomes are each
composed of two chromatids.
C) haploid, and the chromosomes are
each composed of a single chromatid.
D) haploid, and the
chromosomes are each composed of two chromatids.
E) tetraploid,
and the chromosomes are each composed of two chromatids.
D
For a species with a haploid number of 23 chromosomes, how many
different combinations of maternal and paternal chromosomes are
possible for the gametes?
A) 23
B) 46
C) 460
D) 920
E) about 8 million
E
There is a group of invertebrate animals called rotifers, among which
a particular group of species reproduces, as far as is known, only
asexually. These rotifers, however, have survived a long evolutionary
history without evidence of having been overcome by excessive
mutations.
61) Assuming that the eggs are diploid,
tetraploid, or partially tetraploid, what mechanism may still occur
without fertilization?
A) meiosis in each generation
B)
meiosis in every second generation
C) independent assortment of
maternal and paternal chromosomes
D) meiosis in times of
adverse environmental conditions
E) crossing over of homologs
E