Week 7 Quiz

At the start of mitosis, how many centromeres are present in a human cell? A. 46 B. 23 C. 12 D. 92

A

Cellular crawling motion is accomplished by the polymerization of microfilaments along the leading edge with contraction of microfilaments along the trailing edge through the action of myosin the polymerization of microtubules along the leading edge with contraction of microfilaments along the trailing edge through the action of myosin the polymerization of microfilaments along the trailing edge with contraction of microfilaments along the leading edge through the action of myosin the polymerization of microfilaments along the leading edge with contraction of microfilaments along the trailing edge through the action of kinesin the polymerization of microfilaments along the leading edge with contraction of microfilaments along the trailing edge through the action of dynein

A

Signal amplification relies on: A. a sequential increase in the different components of the signal transduction pathway. B. increasing numbers of cell-surface receptors as the signal is transduced. C. increased activity of protein phosphatases. D. increasing amounts of ligand as signal transduction proceeds.

A

What best describes the cytoskeletal element intermediate filaments branched network found in the cell cortex the widest diameter of cytoskeletal structures a double helix of polymerized actin proteins the narrowest diameter of cytoskeletal structures

A

What best describes the cytoskeletal element microtubules A. hollow tube-like structures made of polymerized tubulin protein dimers strong fibers of more than a hundred different types the narrowest diameter of cytoskeletal structures branched network found in the cell cortex

A

What best describes the cytoskeletal element microtubules hollow tube-like structures made of polymerized tubulin protein dimers strong fibers of more than a hundred different types the narrowest diameter of cytoskeletal structures branched network found in the cell cortex

A

What happens to CDK in the absence of cyclin? A. It is inactive. B. It is degraded. C. It becomes phosphorylated. D. Answers a and c are both correct.

A

Which of the following statements concerning cyclin-dependent kinases (CDKs) is NOT true? A. CDKs are inactive, or "turned off," in the presence of cyclins. B. CDKs are active, or "turned on," when complexed with cyclins. C. CDKs are enzymes that attach phosphate groups to other proteins. D. CDKs are present throughout the cell cycle.

A

Given that the correct number of chromosomes is vital to the proper functioning of a cell, which of the statements below is correct if a cell passes from G1 to S phase in the cell cycle? A. The cell copies its chromosomes and enters G2 or returns to G1. B. The cell completes the process of cell division or it dies. C. The cell divides or returns to G1 and enters G0.

B

At the start of mitosis, how many sister chromatids are present in a human cell? A. 46 B. 92 C. 23 D. 12

B

The activation of protein kinase A by cyclic AMP binding likely occurs because of: A. the binding of GTP. B. a conformation change. C. phosphorylation. D. the activity of a phosphatase.

B

What motor proteins are responsible for the activity of the contractile ring during cytokinesis in animal cells? A. dynein B. myosin C. dynamin D. kinesin

B

A cell in prophase I of meiosis has ______________ as much DNA as each of the daughter cells following cytokinesis of meiosis II. A. twice B. half C. four times D. one-quarter

C

A human cell with a total of 23 chromosomes would be considered: A. diploid. B. polyploid. C. haploid. D. euploid.

C

Another name for non-sister chromatids is: A. bivalents. B. diploids. C. homologous chromosomes. D. chiasmata.

C

Dynamic instability of microtubules is caused by the large size of this type of cytoskeletal element results from a deficiency of tubulin dimers available allows microtubules to perform their functions is shared by other cytoskeletal elements All of the above are true

C

Given that the correct number of chromosomes is vital to the proper functioning of a cell, which of the statements below is correct if a cell passes from G1 to S phase in the cell cycle? A. The cell divides or returns to G1 and enters G0. B. The cell copies its chromosomes and enters G2 or returns to G1. C. The cell completes the process of cell division or it dies.

C

How do mitogen-activated protein kinases become inactive? A. Receptor kinases move apart in the membrane. B. Ras hydrolyzes GTP to GDP. C. Phosphatases remove phosphate groups. D. Ligand diffuses away from the ligand-binding site.

C

Which checkpoint would become active if a chromosome was not properly aligned on the spindle? A. G1/S phase checkpoint B. G2/M phase checkpoint C. M phase checkpoint D. None of the above are correct.

C

Which of the following happens during prophase I of meiosis? A. recombination between sister chromatids of homologous chromosomes B. recombination between sister chromatids of non-homologous chromosomes C. recombination between non-sister chromatids of homologous chromosomes D. recombination between non-sister chromatids of non-homologous chromosomes

C

Which of the following second messengers is derived from membrane lipids? A. cAMP B. calmodulin C. DAG D. the alpha subunit of the G-protein

C

A human cell with a total of 23 chromosomes would be considered: A. diploid. B. euploid. C. polyploid. D. haploid.

D

How does meiosis generate genetic diversity? A. crossing over B. random alignment at metaphase 1 C. synapsis D. Answers a and b are both correct.

D

Microtubules grow longer more quickly at one end than the other by growing outward from the centrosome in cycles following rapid depolymerization if tubulin is available All of the above are true

D

The development of a cancer requires both the _______ of an oncogene and the ________ of a tumor suppressor. A. activation; activation B. inhibition; inhibition C. inhibition; activation D. activation; inhibition

D

Which of the following has the most similarity in nucleotide sequence? A. complementary strands of DNA B. non-homologous chromosomes C. homologous chromosomes D. sister chromatids E. maternal and paternal versions of the same chromosome

D

Cancer can be characterized by a mass of rapidly dividing cells called a tumor metastasized tumor cells that leave the tumor and invade distant parts of the body cells that express of a type of intermediate filament that is inappropriate for the tissue type All of the above characterize cancers

all of the above

A cell in prophase I of meiosis has ______________ as much DNA as each of the daughter cells following cytokinesis of meiosis II. A. half B. four times C. one-quarter D. twice

b

Cell shapes are largely determined by cytoskeletal protein networks in the cytoplasm adhesion proteins that assemble at cell surfaces a mesh of proteins and polysaccharides in the extracellular matrix all of the above

d