Deck 16: Development,stem Cells,and Cancer

Question 1

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.

Answer 1

D

Question 2

A Drosophila female has a homozygous mutation for a maternal effect gene.Which of the following results would occur due to this mutation?

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.

Answer 2

B

Question 3

Imagine you are a doctor,and a patient comes to you with type I diabetes and needs treatment.Which of the following types of cells would provide the most effective treatment?

A)embryonic stem cells
B)adult stem cells
C)adult somatic cells
D)gametes

Answer 3

A

Question 4

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

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

Question 5

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.

Question 6

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 7

If a lethal mutation occurs in an embryo,what might be the result?

A)phenotypes that prevent fertilization
B)failure to express maternal effect genes
C)death during development
D)phenotypes that are never born/hatched

Question 8

Which of the following events 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

Question 9

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.Which process in development do these actions compare to?

A)morphogenesis
B)determination
C)induction
D)pattern formation

Question 10

Which of the following characteristics would a mutation in the bicoid gene in Drosophila most likely effect?

A)egg polarity
B)the dorsal-ventral axis
C)segmentation
D)the anterior-posterior axis

Question 11

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.

Question 12

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

Question 13

Entire plants can be cloned from individual somatic cells.What phenomenon does this demonstrate?

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.

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

Question 15

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 16

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 17

Cloned animals often die prematurely.Which of the following processes explains why this can occur?

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 18

Which of the following processes must be performed on adult somatic cells in order to induce them to become pluripotent stem 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 19

Which of the following processes can be used to clone animals?

A)use of mitochondrial DNA from adult female cells of another individual
B)replication and dedifferentiation of adult stem cells from bone marrow
C)separation of an early stage blastula into separate cells,followed by incubation in a surrogate
D)fusion of an adult cell's nucleus with an enucleated egg,followed by incubation in a surrogate

Question 20

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 chromosome inactivation in the embryo is random and produces different patterns in each individual.

Question 21

Which type(s)of cancer is the APC gene most associated with?

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

Question 22

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 23

Which of the following would result from a mutation in a proto-oncogene?

A)normal suppression of tumor growth
B)normal stimulation of cell growth and division
C)abnormal stimulation of cell growth and division
D)reduction in tumor size

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

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 26

Which of the following processes would result from a mutation in the ras gene?

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

Question 27

Forms of the p53 protein found in tumors usually cause which of the following?

A)activation of DNA repair
B)activation of apoptosis
C)cell division to stop
D)excessive cell growth

Question 28

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 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

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 31

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)BRCA1 and BRCA2

Question 32

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.

Question 33

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 34

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.