ch. 11 learning curve

Which of the following statements about viruses are true? a. Viruses contain multiple genes, and each of these genes is an oncogene. b. Viruses are a type of prokaryotic cell. c. Viruses are the root cause of most—if not all—cancers. d. Human cancers have not been associated with viruses. e. None of the answer options is correct.

e. None of the answer options is correct.

A human cell with a total of 23 chromosomes is:

haploid

Some types of leukemia are the result of constitutively active (i.e., "always on") growth factor receptors. T or F?

true

How many chromosome pairs are there in a normal human genome?

23

At the start of mitosis, how many centromeres are present in a human cell?

46

Evidence exists (especially in dinoflagellates) that mitosis evolved from binary fission. For example, in certain eukaryotic cells during mitosis, DNA is attached to the membrane of the nucleus (much like a circular chromosome of a bacterium is attached to the plasma membrane). T or F?

True

What is the role of the protein FtsZ? a. It forms a ring at the site of constriction. b. It is responsible for the replication of DNA. c. It is involved in the attachment of DNA to the plasma membrane. d. It forms the new cell wall between daughter cells.

a. It forms a ring at the site of constriction.

Why would a compound that interferes with bacterial cell wall synthesis be useful for treating a bacterial infection? a. It would limit the spread of the infection through cell division. b. It would prevent the cells from becoming larger. c. It would prevent replication of DNA. d. It would prevent replication of DNA, and it would limit the spread of the infection.

a. It would limit the spread of the infection through cell division.

Why don't plant cells use a contractile ring to divide their daughter cells? a. Plant cells don't have plasma membranes. b. A contractile ring can't "pinch" a cell wall. c. Plant cells don't form daughter cells. d. Plant cells don't have an actin cytoskeleton.

b. A contractile ring can't "pinch" a cell wall.

Muscle cells in the mammalian heart are multinucleate, meaning that multiple nuclei are present in the cytoplasm of a large cell. Predict what is different about the cell cycle in a muscle cell. a. The G1 and G2 phases are extended. b. Cytokinesis does not occur. c. M phase is inhibited. d. S phase happens twice.

b. Cytokinesis does not occur.

Which one of the following statements regarding the S cyclin-CDK complex is true? a. It regulates the expression of histone proteins. b. It ensures that DNA is not replicated multiple times. c. It is responsible for the phosphorylation of nuclear proteins. d. It is regulated solely by the action of p53. e. It is responsible for the degradation of nuclear membranes.

b. It ensures that DNA is not replicated multiple times.

A woman has her genome sequenced and finds that she carries a mutation in p53. Will she develop cancer? a. Yes, she will certainly develop cancer given the role of p53 in the cell cycle. b. Possibly—this mutation may predispose her to developing certain types of cancer. c. No, mutations in p53 do not contribute to cancer.

b. Possibly—this mutation may predispose her to developing certain types of cancer.

Which of the following is not true regarding CDKs? a. They bind to cyclin. b. The levels of CDK change with the cell cycle. c. They function as a kinase. d. They function to control the cell cycle.

b. The levels of CDK change with the cell cycle.

A phragmoplast functions to: a. anchor microtubules to sister chromatids. b. form a new cell wall. c. break down the nuclear envelope. d. stimulate the growth of the microtubule spindle.

b. form a new cell wall.

What is the function of histone proteins? a, to connect chromosomes to the mitotic spindle b. to package DNA in eukaryotic chromosomes c. to organize the microtubules that make up the spindle d. to attach sister chromatids together

b. to package DNA in eukaryotic chromosomes

Predict what would happen if crossing over between homologous chromosomes occurred as part of mitosis. a. Daughter cells could contain two copies of the same allele. b. There would be no effect since sister chromatids separate in anaphase. c. Daughter cells would not be genetically identical, and they could contain two copies of the same allele. d. Daughter cells would not be genetically identical.

c. Daughter cells would not be genetically identical, and they could contain two copies of the same allele.

At which checkpoint would a cell become arrested if a chromosome was not properly aligned in the spindle? a. at a checkpoint late in G1 b. at a checkpoint late in G2 c. at a checkpoint early in the mitotic phase d. None of the answer options is correct.

c. at a checkpoint early in the mitotic phase

The process of cell division in a prokaryotic cell is called: a. binary fusion. b. mitosis. c. binary fission. d. cytokinesis.

c. binary fission.

Polar bodies are: a. produced by mitosis. b. functional gametes that are produced by mitosis. c. haploid cells. d. functional gametes that are produced by meiosis

c. haploid cells.

The division of genetic material in a eukaryotic cell is called: a. replication. b. genetic fission. c. mitosis. d. cytokinesis.

c. mitosis

The division of genetic material in a eukaryotic cell is called: a. genetic fission. b. cytokinesis. c. mitosis. d. replication.

c. mitosis.

What happens to CDKs in the absence of cyclins? a. They become phosphorylated. b. They are inactive and become phosphorylated. c. They are inactive. d. They are degraded.

c.. They are inactive.

Asexual reproduction occurs in: unicellular eukaryotes. a. animal cells. b. plant cells. c. bacterial cells. d. All of these choices are correct.

d. All of these choices are correct.

What would happen if a chromosome only connected to the mitotic spindle at one of its kinetochores? a. One of the daughter cells would have an extra copy of that chromosome. b. The sister chromatids would not separate. c. The chromosome would not line up properly at metaphase. d. All of these choices are correct.

d. All of these choices are correct.

How must spindle microtubules attach to chromosomes during prometaphase of meiosis I? a. Spindle microtubules from one pole must attach to both kinetochores in a pair of sister chromatids. b. Microtubules attach at the centrosomes. c. Spindle microtubules from one pole attach to one kinetochore, and spindle microtubules from the other pole attach to the other kinetochore in a pair of sister chromatids, just like in mitosis. d. Microtubules attach to the chiasma. e. Microtubules attach using their minus (slow assembling) ends.

a. Spindle microtubules from one pole must attach to both kinetochores in a pair of sister chromatids.

The development of cancer requires both the _____ of an oncogene and the _____ of a tumor suppressor. a. activation; inhibition b. activation; activation c. inhibition; inhibition d. inhibition; activation

a. activation; inhibition

In which phase of mitosis do spindle microtubules shorten? a. anaphase b. metaphase c. telophase d. prophase

a. anaphase

During what step in meiosis do the daughter cells become haploid? a. anaphase I b. metaphase II c. prophase II d. anaphase II

a. anaphase I

The division of the cell's cytoplasm in a eukaryotic cell is known as: a. cytokinesis. b. cell fission. c. mitosis. d. both cytokinesis and mitosis.

a. cytokinesis.

The assembly of what cytoskeletal protein is initiated by the M cyclin-CDK complex? a. microtubules b. microfilaments c. intermediate filaments d. All of these choices are correct.

a. microtubules

Which of the following is not a step in the process of binary fission? a. rearrangement of the microtubule cytoskeleton b. elongation of the cell c. replication of DNA d. formation of a new cell wall

a. rearrangement of the microtubule cytoskeleton

Which of the following statements is true regarding binary fission? a. Proteins only anchor the original circular genome to the plasma membrane; the copy produced by DNA replication is free-floating. b. In binary fission, cell division is typically asymmetrical, with one daughter cell appearing much smaller than the other. c. Tubulin, rather than FtsZ, is responsible for cell division during binary fission. d. DNA replication during binary fission is a bidirectional process, occurring in opposite directions. e. None of the answer options is correct.

d. DNA replication during binary fission is a bidirectional process, occurring in opposite directions.

Which of the following is not a characteristic of meiotic cell division? a. Cell division requires two rounds of nuclear division. b. Cell division results in the production of gametes. c. Cell division results in the formation of four daughter cells. d. Daughter cells are genetically identical.

d. Daughter cells are genetically identical.

What would happen if crossing over occurred between sister chromatids? a. Genetic diversity would decrease due to the loss of gene combinations. b. Genetic diversity would increase due to the addition of gene combinations. c. Gene rearrangement would lead to changes in gene expression. d. Nothing would happen because sister chromatids are genetically identical or nearly identical.

d. Nothing would happen because sister chromatids are genetically identical or nearly identical.

When in the cell cycle would you find sister chromatids? a. S b. G1 c. G2 d. S and G2

d. S and G2

What would happen to the daughter cells if the G2 phase of the parent cell is shortened? a. The cells would not undergo cytokinesis. b. The cells would be missing chromosomes. c. The cells would be larger than normal. d. The cells would be smaller than normal.

d. The cells would be smaller than normal.

Which of the following is not true regarding CDKs? a. They function as a kinase. b. They bind to cyclin. c They function to control the cell cycle. d. The levels of CDK change with the cell cycle.

d. The levels of CDK change with the cell cycle.

Why are the X and Y chromosomes not considered homologous? a. They come from different parents. b. They do not carry the same set of genes. c. Mammalian males carry two very different chromosomes. d. They do not carry the same set of genes, and mammalian males carry two very different sex chromosomes.

d. They do not carry the same set of genes, and mammalian males carry two very different sex chromosomes.

The microtubules that form the mitotic spindle extend out from the centrosome. Where would you expect to find the plus (fast assembling) end of a spindle microtubule? a. away from the centrosome b. at the centrosome c. at the kinetochore d. away from the centrosome, at the kinetochore

d. away from the centrosome, at the kinetochore

Synapsis is best described as: a. the exchange of genetic information between non-sister chromatids. b. the alignment of non-sister chromatids at the metaphase plate. c. the exchange of genetic information between sister chromatids. d. the pairing of homologous chromosomes in prophase I.

d. the pairing of homologous chromosomes in prophase I.

What is the function of the centromere? a. to attach the chromosome to the spindle b. to organize the microtubules to form a spindle c. to attach the DNA to the plasma membrane d. to attach the sister chromatids to each other

d. to attach the sister chromatids to each other

How does a cell regulate the progression of the cell cycle? a. through the expression and synthesis of cyclin proteins b. through checkpoints c. through the expression and synthesis of CDKs d. through destruction of cyclins e. All of these choices are correct.

e. All of these choices are correct.

The prokaryotic protein FtsZ is evolutionarily related to eukaryotic tubulin. What does this mean? a. The gene sequence for FtsZ is similar to tubulin. b. The amino acid sequence for FtsZ is similar to tubulin. c. The overall protein structure of FtsZ is similar to tubulin. d. The two proteins evolved from a common ancestral protein. e. All of these choices are correct.

e. All of these choices are correct.

Which of the following statements regarding cancer—according to Hanahan and Weinberg—are true? a. Cancer cells typically secrete factors that promote blood vessel formation. b. Cancer cells can sometimes metastasize and travel throughout the body. c. Mutations in growth factor receptors are sometimes required for cancer cell division. d. Cancer cells can resist cell-death signals. e. All of these choices are correct.

e. All of these choices are correct.

A graduate student is planning an experiment to evaluate the expression of PDGF-related genes in her cell population of interest. As a control, she hopes to confirm the expression of genes that are present in all dividing cells. For her controls, she should evaluate the expression of: a. PDGF. b. laminin. c. G proteins. d. Notch. e. CDKs.

e. CDKs.