1) Pax-6 is a gene that is involved in eye formation in many invertebrates, such as Drosophila.
Pax-6 is found as well in vertebrates. A Pax-6 gene from a mouse can be expressed in a fly and
the protein (PAX-6) leads to a compound fly eye. This information suggests which of the
following?
A) Pax-6 genes are identical in nucleotide sequence.
B) PAX-6 proteins have identical amino acid sequences.
C) Pax-6 is highly conserved and shows shared evolutionary ancestry.
D) PAX-6 proteins are different for formation of different kinds of eyes.
E) PAX-6 from a mouse can function in a fly, but a fly's Pax-6 gene cannot function in a mouse.
c
2) What is considered to be the first evidence of differentiation in
the cells of an embryo?
A) cell division occurring after
fertilization
B) the occurrence of mRNAs for the production of
tissue-specific proteins
C) determination of specific cells for
certain functions
D) changes in the size and shape of the
cell
E) changes resulting from induction
b
3) Embryonic lethal mutations result in
A) phenotypes that
prevent fertilization.
B) failure to express maternal effect
genes.
C) death during pupation.
D) phenotypes that are
never born/hatched.
E) homeotic phenotype changes.
d
4) Your brother has just purchased a new plastic model airplane. He
places all the parts on the
table in approximately the positions
in which they will be located when the model is complete.
His
actions are analogous to which process in development?
A)
morphogenesis
B) determination
C) induction
D)
differentiation
E) pattern formation
e
5) The product of the bicoid gene in Drosophila provides essential
information about
A) lethal genes.
B) the dorsal-ventral
axis.
C) the left-right axis.
D) segmentation.
E) the
anterior-posterior axis.
e
6) If a Drosophila female has a homozygous mutation for a maternal
effect gene,
A) she will not develop past the early embryonic
stage.
B) all of her offspring will show the mutant phenotype,
regardless of their genotype.
C) only her male offspring will
show the mutant phenotype.
D) her offspring will show the mutant
phenotype only if they are also homozygous for
the
mutation.
E) only her female offspring will show the
mutant phenotype.
b
7) Mutations in which of the following genes lead to transformations
in the identity of entire
body parts?
A) morphogens
B)
segmentation genes
C) egg-polarity genes
D) homeotic
genes
E) inducers
d
8) Which of the following genes map out the basic subdivisions along
the anterior-posterior axis
of the Drosophila embryo?
A)
homeotic genes
B) segmentation genes
C) egg-polarity
genes
D) morphogens
E) inducers
b
9) The bicoid gene product is normally localized to the anterior end
of the embryo. If large
amounts of the product were injected into
the posterior end as well, which of the following
would
occur?
A) The embryo would grow to an unusually large
size.
B) The embryo would grow extra wings and legs.
C) The
embryo would probably show no anterior development and die.
D)
Anterior structures would form in both sides of the embryo.
E)
The embryo would develop normally.
d
10) The fact that plants can be cloned from somatic cells
demonstrates that
A) differentiated cells retain all the genes of
the zygote.
B) genes are lost during differentiation.
C) the
differentiated state is normally very unstable.
D) differentiated
cells contain masked mRNA.
E) differentiation does not occur in plants.
a
11) Which of the following is most closely identical to the formation
of twins?
A) cell cloning
B) therapeutic cloning
C) use
of adult stem cells
D) embryo transfer
E) organismal cloning
e
12) In 1997, Dolly the sheep was cloned. Which of the following
processes was used?
A) use of mitochondrial DNA from adult female
cells of another ewe
B) replication and dedifferentiation of
adult stem cells from sheep bone marrow
C) separation of an
early-stage sheep blastula into separate cells, one of which was
incubated in a
surrogate ewe
D) fusion of an adult
cell's nucleus with an enucleated sheep egg, followed by
incubation in a
surrogate
E) isolation of stem cells from a
lamb embryo and production of a zygote equivalent
d
13) Which of the following problems with animal cloning might result
in premature death of the
clones?
A) use of pluripotent
instead of totipotent stem cells
B) use of nuclear DNA as well as
mtDNA
C) abnormal gene regulation due to variant
methylation
D) the indefinite replication of totipotent stem
cells
E) abnormal immune function due to bone marrow dysfunction
c
14) Reproductive cloning of human embryos is generally considered
unethical. However, on the
subject of therapeutic cloning there
is a wider divergence of opinion. Which of the following is
a
likely explanation?
A) Use of adult stem cells is likely
to produce more cell types than use of embryonic stem cells.
B)
Cloning to produce embryonic stem cells may lead to great medical
benefits for many.
C) Cloning to produce stem cells relies on a
different initial procedure than reproductive cloning.
D) A clone
that lives until the blastocyst stage does not yet have human
DNA.
E) No embryos would be destroyed in the process of
therapeutic cloning.
b
15) Which of the following is true of embryonic stem cells but not of
adult stem cells?
A) They normally differentiate into only eggs
and sperm.
B) They can give rise to all cell types in the
organism.
C) They can continue to reproduce for an indefinite
period.
D) They can provide enormous amounts of information about
the process of gene regulation.
E) One aim of using them is to
provide cells for repair of diseased tissue.
b
16) A researcher is using adult stem cells and comparing them to
other adult cells from the same
tissue. Which of the following is
a likely finding?
A) The cells from the two sources exhibit
different patterns of DNA methylation.
B) Adult stem cells have
more DNA nucleotides than their counterparts.
C) The two kinds of
cells have virtually identical gene expression patterns in
microarrays.
D) The nonstem cells have fewer repressed
genes.
E) The nonstem cells have lost the promoters for more genes.
a
17) In animals, what is the difference between reproductive cloning
and therapeutic cloning?
A) Reproductive cloning uses totipotent
cells, whereas therapeutic cloning does not.
B) Reproductive
cloning uses embryonic stem cells, whereas therapeutic cloning does
not.
C) Therapeutic cloning uses nuclei of adult cells
transplanted into enucleated nonfertilized eggs.
D) Therapeutic
cloning supplies cells for repair of diseased or injured organs.
d
18) The first cloned cat, called Carbon Copy, was a calico, but she
looked significantly different
from her female parent.
Why?
A) The environment, as well as genetics, affects phenotypic
variation.
B) Fur color genes in cats are influenced by
differential acetylation patterns.
C) Cloned animals have been
found to have a higher frequency of transposon activation.
D) X
inactivation in the embryo is random and produces different
patterns.
E) The telomeres of the parent's chromosomes
were shorter than those of an embryo.
d
19) In recent times, it has been shown that adult cells can be
induced to become pluripotent stem
cells (iPS). In order to make
this conversion, what has been done to the adult cells?
A) A
retrovirus is used to introduce four specific regulatory
genes.
B) The adult stem cells must be fused with embryonic
cells.
C) Cytoplasm from embryonic cells is injected into the
adult cells.
D) An adenovirus vector is used to transfer
embryonic gene products into adult cells.
E) The nucleus of an
embryonic cell is used to replace the nucleus of an adult cell.
a
20) Let us suppose that someone is successful at producing induced
pluripotent stem cells (iPS)
for replacement of pancreatic
insulin-producing cells for people with type 1 diabetes. Which
of
the following could still be problematic?
I. the
possibility that, once introduced into the patient, the iPS cells
produce nonpancreatic cells
II. the failure of the iPS cells to
take up residence in the pancreas
III. the inability of the iPS
cells to respond to appropriate regulatory signals
A) I
only
B) II only
C) III only
D) I and II
E) all of them
e
21) In animals, embryonic stem cells differ from adult stem cells in
that
A) embryonic stem cells can differentiate into more cell
types than adult stem cells.
B) adult stem cells can
differentiate into more cell types than embryonic stem cells.
C)
embryonic stem cells have more genes than adult stem cells.
D)
embryonic stem cells have fewer genes than adult stem cells.
E)
embryonic stem cells are localized to specific sites within the
embryo, whereas adult stem
cells are spread throughout the body.
a
22) Which of the following statements describes
proto-oncogenes?
A) Their normal function is to suppress tumor
growth.
B) They are introduced to a cell initially by
retroviruses.
C) They are produced by somatic mutations induced
by carcinogenic substances.
D) They can code for proteins
associated with cell growth.
E) They are underexpressed in cancer cells.
d
23) Which of the following is characteristic of the product of the
p53 gene?
A) It is an activator for other genes.
B) It
speeds up the cell cycle.
C) It causes cell death via
apoptosis.
D) It allows cells to pass on mutations due to DNA
damage.
E) It slows down the rate of DNA replication by
interfering with the binding of DNA
polymerase.
a
24) Tumor-suppressor genes
A) are frequently overexpressed in
cancerous cells.
B) are cancer-causing genes introduced into
cells by viruses.
C) can encode proteins that promote DNA repair
or cell-cell adhesion.
D) often encode proteins that stimulate
the cell cycle.
E) do all of the above.
c
25) BRCA1 and BRCA2 are considered to be tumor-suppressor genes
because
A) they prevent infection by tumor viruses that cause
cancer.
B) their normal products participate in repair of DNA
damage.
C) the mutant forms of either one of these prevent breast
cancer.
D) the normal genes make estrogen receptors.
E) they
block penetration of breast cells by chemical carcinogens.
b
26) The cancer-causing forms of the Ras protein are involved in which
of the following
processes?
A) relaying a signal from a
growth factor receptor
B) DNA replication
C) DNA
repair
D) cell-cell adhesion
E) cell division
a
27) Forms of the Ras protein found in tumors usually cause which of
the following?
A) DNA replication to stop
B) DNA replication
to be hyperactive
C) cell-to-cell adhesion to be
nonfunctional
D) cell division to cease
E) growth factor
signaling to be hyperactive
e
28) A genetic test to detect predisposition to cancer would likely
examine the APC gene for
involvement in which type(s) of
cancer?
A) colorectal only
B) lung and breast
C) small
intestinal and esophageal
D) lung only
E) lung and prostate
a
29) In colorectal cancer, several genes must be mutated in order to
contribute to a cell
developing into a cancer cell, supporting
Knudsen's hypothesis. Which of the following kinds
of
genes would you expect to be mutated?
A) genes coding for
enzymes that act in the colon
B) genes involved in control of the
cell cycle
C) genes that are especially susceptible to
mutation
D) the same genes that Knudsen identified as associated
with retinoblastoma
E) the genes of the bacteria that are
abundant in the colon
b
1) Muscle cells differ from nerve cells mainly because they
A)
express different genes.
B) contain different genes.
C) use
different genetic codes.
D) have unique ribosomes.
E) have
different chromosomes.
a
2) Cell differentiation always involves
A) the production of
tissue-specific proteins, such as muscle actin.
B) the movement
of cells.
C) the transcription of the myoD gene.
D) the
selective loss of certain genes from the genome.
E) the
cell's sensitivity to environmental cues, such as light or heat.
a
3) Apoptosis involves all but which of the following?
A)
fragmentation of the DNA
B) cell-signaling pathways
C)
activation of cellular enzymes
D) lysis of the cell
E)
digestion of cellular contents by scavenger cells
d
4) Absence of bicoid mRNA from a Drosophila egg leads to the absence
of anterior larval body
parts and mirror-image duplication of
posterior parts. This is evidence that the product of the
bicoid
gene
A) is transcribed in the early embryo.
B) normally
leads to formation of tail structures.
C) normally leads to
formation of head structures.
D) is a protein present in all head
structures.
E) leads to programmed cell death.
c
5) Proto-oncogenes can change into oncogenes that cause cancer. Which
of the following best
explains the presence of these potential
time bombs in eukaryotic cells?
A) Proto-oncogenes first arose
from viral infections.
B) Proto-oncogenes normally help regulate
cell division.
C) Proto-oncogenes are genetic
"junk."
D) Proto-oncogenes are mutant versions
of normal genes.
E) Cells produce proto-oncogenes as they age.
b