Ch 18 Part 3

Front 1

In animals, embryonic stem cells differ from adult stem cells in that
A) embryonic stem cells are totipotent, and adult stem cells are pluripotent.
B) embryonic stem cells are pluripotent, and adult stem cells are totipotent.
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.

Back 1

embryonic stem cells are totipotent, and adult stem cells are pluripotent.

Front 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

Back 2

the occurrence of mRNAs for the production of tissue-specific proteins

Front 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.

Back 3

phenotypes that are never born/hatched.

Front 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

Back 4

pattern formation

Front 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.

Back 5

the anterior-posterior axis.

Front 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.

Back 6

all of her offspring will show the mutant phenotype, regardless of their genotype.

Front 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

Back 7

homeotic genes

Front 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

Back 8

segmentation genes

Front 9

Gap genes and pair-rule genes fall into which of the following categories?
A) homeotic genes
B) segmentation genes
C) egg-polarity genes
D) morphogens
E) inducers

Back 9

segmentation genes

Front 10

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.

Back 10

Anterior structures would form in both sides of the embryo.

Front 11

What do gap genes, pair-rule genes, segment polarity genes, and homeotic genes all have in common?
A) Their products act as transcription factors.
B) They have no counterparts in animals other than Drosophila.
C) Their products are all synthesized prior to fertilization.
D) They act independently of other positional information.
E) They apparently can be activated and inactivated at any time of the fly's life.

Back 11

Their products act as transcription factors.

Front 12

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.

Back 12

They can code for proteins associated with cell growth.

Front 13

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.

Back 13

It is an activator for other genes.

Front 14

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.

Back 14

can encode proteins that promote DNA repair or cell-cell adhesion.

Front 15

BRCA1 and BRCA2 are considered to be tumor-suppressor genes because
A) they prevent infection by retroviruses that cause cancer.
B) their normal products participate in repair of DNA damage.
C) the mutant forms of either one of these promote breast cancer.
D) the normal genes make estrogen receptors.
E) they block penetration of breast cells by chemical carcinogens.

Back 15

their normal products participate in repair of DNA damage.

Front 16

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

Back 16

relaying a signal from a growth factor receptor

Front 17

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

Back 17

growth factor signaling to be hyperactive

Front 18

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

Back 18

colorectal only

Front 19

Drosophila embryo after about 2 hours.

At this point, the embryo is characterized as
A) a first-stage larva.
B) nuclei in the cortex that has not undergone cytokinesis.
C) nuclei in the cortex forming a single-cell layer over the surface.
D) an embryo with segmentation beginning to be apparent.

Back 19

nuclei in the cortex forming a single-cell layer over the

Front 20

The four sequestered cells at one end are most probably destined to become
A) the legs of the adult fly.
B) the germ cells of the adult.
C) mouthparts.
D) antennae.
E) wing primordial.

Back 20

the germ cells of the adult.