AP Biology Review: Ch. 11-12

The centromere is a region in which

chromatids remain attached to one another until anaphase.

which of the following describes cyclin-dependent kinase (Cdk)?

Cdk is present throughout the cell cycle and Cdk is an enzyme that attached phosphate groups to other proteins. (Both b and c)

Consider this pathway: epinephrine → G protein-coupled receptor → G protein → adenylyl cyclase→ cAMP. Identify the second messenger.

cAMP

a protein maintained at constant levels throughout the cell cycle that requires cyclin to become catalytically active

cdk

Sutherland discovered that epinephrine signals

elevation of cytosolic concentrations of cyclic AMP.

If there are 20 chromatids in a cell, how many centromeres are there?

10

A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA per nucleus. Those cells would have_______ picograms at the end of the s phase and _______ at the end of G2.

16;16

which of the following is released by platelets in the vicinity of an injury?

PDGF

For a newly evolving protist, what would be the advantage of using eukaryote-like cell division rather than binary fission?

Cell division would allow for the orderly and efficient segregation of multiple linear chromosomes

Nerve and muscle cells are in this phase:

G0

A particular cell has half as much DNA as some other cells in a mitotically active tissue. The cell in question is most likely in

G1

Which observation suggested to Sutherland the involvement of a second messenger in epinephrine'seffect on liver cells?

Glycogen breakdown was observed only when epinephrine was administered to intact cells.

Lipid-soluble signaling molecules, such as testosterone, cross the membranes of all cells but affectonly target cells because

Intracellular receptors are present only in target cells.

Which of the following describes the events of apoptosis?

Its DNA and organelles are fragmented, the cell shrinks and forms blebs, and the cell self-digests.

This is the shortest part of the cell cycle:

M

which of the following triggers the cell's passage past the G2 checkpoint into mitosis?

MPF

If the cells in the process of dividing are subjected to colchicine, a drug that interferes with the functioning of the spindle apparatus, at which stage will mitosis be arrested?

Metaphase

Which is the longest of the mitotic stages?

Metaphase

Which of the following statements is true of signal molecules?

Protein kinase A activation is one possible result of signal molecules binding to G protein-coupled receptors.

How do daughter cells at the end of mitosis and cytokinesis compare with their parent cell when it was in G1 of the cell cycle?

The daughter cells have the same number of chromosomes and the same amount of DNA.

What is most likely to happen to an animal's target cells that lack receptors for local regulators?

They might not be able to multiply in response to growth factors from nearby cells.

Several organisms, primarily protists, have what are called intermediate mitotic organization. what is the most probable hypothesis about these intermediate forms of cell division?

They show some of the evolutionary steps toward complete mitosis but not all.

Nucleotides can be radiolabeled before they are incorporated into newly forming DNA and can therefore be assayed to track their incorporation. in a set of experiments, a student- faculty research team used labeled T nucleotides and introduced these into the culture of dividing human cells at specific times. which of the following questions might be answered by such a method?

What is the length of the s phase of the cell cycle?

The formation of a cell plate is beginning across the middle of a cell and nuclei are re-forming at opposite ends of the cell. What kind of cell is this?

a plant cell undergoing cytkinesis

The MPF protein turns itself off by

activating a process that destroys cyclin component.

A major group of G protein-coupled receptors contains seven transmembrane α helices. The amino end ofthe protein lies at the exterior of the plasma membrane. Loops of amino acids connect the helices either at the exterior face or on the cytosol face of the membrane. The loop on the cytosol side between helices 5 and 6 is usually substantially longer than the others. Where would you expect to find the carboxyl end?

at the cytosol surface

A major group of G protein-coupled receptors contains seven transmembrane α helices. The amino end ofthe protein lies at the exterior of the plasma membrane. Loops of amino acids connect the helices either at the exterior face or on the cytosol face of the membrane. The loop on the cytosol side between helices 5 and 6 is usually substantially longer than the others. The coupled G protein most likely interacts with this receptor

at the loop between H5 and H6

In general, a signal transmitted via phosphorylation of a series of proteins

brings a conformational change to each protein.

Proteins that are involved in the regulation of the cell cycle, and that show fluctuations in concentration during the cell cycle, are called

cyclins

Vinblastine is a standard chemotherapeutic drug to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to

disruption of mitotic spindle formation

The termination phase of cell signaling requires which of the following?

incompatibility of the binding of the signal molecule to the receptor

What are scaffolding proteins?

large molecules to which several relay proteins attach to facilitate cascade effects

Binding of a signaling molecule to which type of receptor leads directly to a change in the distribution of ions on opposite sides of the membrane?

ligand-gated ion channel

Apoptosis involves all but which of the following? A) fragmentation of the DNA B) cell-signaling pathways C) activation of cellular enzymes D) lysis of the cell E) digestion of cellular contents by scavenger cells

lysis of the cell

which of the following is a function of those spindle microtubules that do not attach to kinetochores?

maintaining the region of overlap of fibers in the cells center.

what is the general term for enzymes that activate or inactivate other proteins by phosphorylating them?

protein kinase

Which of the following most likely would be an immediate result of growth factor binding to its receptor?

protein kinase activity

the decline of MPF activity at the end of mitosis is due to

the degradation of cyclin.

Using the yeast signal transduction pathways, both types of mating cells release the mating factors.These factors bind to specific receptors on the correct cells,

then one cell nucleus binds the mating factors and produces a new nucleus in the opposite cell.

Cytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not cytokinesis, the result would be a cell with

two nuclei