Deck 16: Development, Stem Cells, and Cancer

Question 1

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

Answer 1

D

Question 2

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

Answer 2

B

Question 3

Which of the following statements is a likely explanation for why therapeutic cloning is considered acceptable by many?

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 treatments for a large number of diseases.
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.

Answer 3

B

Question 4

A researcher is using adult stem cells and comparing them to other adult cells from the same tissue. Which of the following statements describes a likely finding of this research?

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 non-stem cells have fewer repressed genes.

Question 5

In animals, which of the following statements describes one 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, whereas reproductive cloning does not.
D) Therapeutic cloning supplies cells that may treat disease, whereas reproductive cloning supplies cells that may be used to produce new individuals.

Question 6

Recent research has shown that adult cells can be induced to become pluripotent stem cells (iPS). In order to make this conversion, what is done to the adult cells?

A) A retrovirus is used to introduce four master regulatory genes.
B) The adult stem cells are fused with embryonic cells.
C) Cytoplasm from embryonic cells is injected into the adult cells.
D) The nucleus of an embryonic cell is used to replace the nucleus of an adult cell.

Question 7

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) abnormal gene regulation due to variant methylation
C) the indefinite replication of totipotent stem cells
D) abnormal immune function due to bone marrow dysfunction

Question 8

The product of the bicoid gene in Drosophila provides essential information about

A) lethal genes.
B) the dorsal-ventral axis.
C) segmentation.
D) the anterior-posterior axis.

Question 9

Which of the following is most like the formation of twins?

A) cell cloning
B) therapeutic cloning
C) use of adult stem cells
D) embryo transfer
E) organismal cloning

Question 10

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

Question 11

Which of the following statements is true of embryonic 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.

Question 12

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

Question 13

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.

Question 14

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

Question 15

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.

Question 16

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.

Question 17

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.

Question 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 in each individual.

Question 19

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 occurrences could still be problematic?

A) the possibility that, once introduced into the patient, the iPS cells produce nonpancreatic cells
B) the success of the iPS cells taking up residence in the pancreas
C) the ability of the iPS cells to respond to appropriate regulatory signals
D) the possibility that, once introduced into the patient, the iPS cells produce only pancreatic cells

Question 20

Pax-6 is a gene that is involved in eye formation in many invertebrates, such as Drosophila. Pax-6 is also found 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.

Question 21

A genetic test to detect predisposition to cancer would likely examine the APC gene for involvement in which type(s) of cancer?

A) colorectal
B) lung and breast
C) small intestinal and esophageal
D) lung only

Question 22

Which of the following statements correctly describes tumor-suppressor genes?

A) They are frequently overexpressed in cancerous cells.
B) They are cancer-causing genes introduced into cells by viruses.
C) They can encode proteins that promote DNA repair or cell-cell adhesion.
D) They often encode proteins that stimulate the cell cycle.

Question 23

Which of the following statements accurately describes one main characteristic of proto-oncogenes?

A) Their normal function is to suppress tumor growth.
B) They are produced by somatic mutations induced by carcinogenic substances.
C) They code for proteins associated with normal cell growth.
D) They are underexpressed in cancer cells.

Question 24

Cell differentiation always involves

A) the transcription of the myoD gene.
B) the movement of cells.
C) the production of tissue-specific proteins.
D) the selective loss of certain genes from the genome.

Question 25

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) normally leads to formation of head structures.
B) normally leads to formation of tail structures.
C) is transcribed in the early embryo.
D) is a protein present in all head structures.

Question 26

Which of the following is characteristic of the product of the p53 gene?

A) It is an activator for other genes.
B) It slows down the cell cycle.
C) It does not cause cell death via apoptosis.
D) It slows down the rate of DNA replication by interfering with the binding of DNA polymerase.

Question 27

Why are the BRCA1 and BRCA2 genes considered to be tumor-suppressor genes?

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) They block penetration of breast cells by chemical carcinogens.

Question 28

Apoptosis involves all but which of the following?

A) fragmentation of the DNA
B) cell-signaling pathways
C) lysis of the cell
D) digestion of cellular contents by scavenger cells

Question 29

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.

Question 30

In colorectal cancer, several genes must be mutated in order to contribute to a cell developing into a cancer cell. 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

Question 31

The cancer-causing forms of the Ras protein are involved in which of the following processes?

A) activation of protein kinases
B) DNA replication
C) DNA repair
D) activation of apoptosis

Question 32

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 are mutant versions of normal genes.
C) Proto-oncogenes are genetic "junk."
D) Proto-oncogenes normally help regulate cell division.

Question 33

Forms of the Ras protein found in tumors usually cause which of the following?

A) DNA replication to be hyperactive
B) cell-to-cell adhesion to be nonfunctional
C) cell division to stop
D) growth factor signaling to be hyperactive

Question 34

Which of the following statements correctly describes one of the differences between embryonic and adult stem cells in animals?

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 fewer genes than adult stem cells.
D) Embryonic stem cells are localized to specific sites within the embryo, whereas adult stem cells are spread throughout the body.