Intro to Cell- Exam 3

What would happen if the kinase that adds the inhibitory phosphate to Cdk were defective?

M phase would begin prematurely.

For the experiment shown in Figure 11.9, which answer correctly states the prediction of the "hypothesis" or "null hypothesis"?

Prediction of hypothesis: Antibodies to some membrane proteins will block cell-cell adhesion.

Cytokinesis in animal cells is accomplished by constriction of the cell along the plane of cell division (formation of a cleavage furrow). In plant cells, which have cell walls, a completely different mechanism of cytokinesis has evolved. Which of the following statements are true of cytokinesis in plant cells? Select the two that apply.

-Vesicles from the Golgi apparatus move along microtubules, coalesce at the plane of cell division, and form a cell plate. -The cell plate consists of the plasma membrane and cell wall that will eventually separate the two daughter cells.

Identify the events in the cell cycle that must be completed successfully for daughter cells to share an identical complement of chromosomes.

-the spindle apparatus must connect with the kinetochores of each sister chromatid in prometaphase -all the chromosomes must be replicated during the S phase -the sister chromatids of each replicated chromosome must be partitioned in anaphase and fully separated into daughter cells by cytokinesis

Drag the labels onto the table to indicate which type(s) of gated ion channels are found in each membrane associated with a chemical synapse. (The letters in the table refer to the lettered structures in the image above.) Labels can be used once, more than once, or not at all.

2, 3, 1, 0, 2

Based on what you have learned about how cells ensure that proteins end up in the right place (Chapter 7), what type of signal would you expect to be exposed on a cytosolic receptor after a steroid hormone changes the receptor's conformation?

Amino acids required for transport through the nuclear pore complex

Which answer correctly associates a phase of mitosis with what happens to chromosomes during that phase?

Anaphase: Sister chromatids separate.

What evidence suggests that during anaphase, kinetochore microtubules shorten at the kinetochore?

Daughter chromosomes were observed to move toward the pole faster than do the marked regions of fluorescently labeled kinetochore microtubules.

Which statement is correct concerning the relationship between chromosomes and either genes, chromatin, or sister chromatids?

Each replicated chromosome consists of two sister chromatids.

Which answer correctly identifies a cell-cycle checkpoint with a criterion for passing it?

G2 checkpoint: Chromosomes have replicated successfully.

Which statement is most accurate concerning how the molecular composition of a plant cell wall compares with the ECM of animal cells?

Plant cell wall fibers consist primarily of carbohydrates; ECM fibers are dominated by proteins.

Some disease-causing microbes attack the body by turning on or off specific signal transduction pathways. In the disease cholera, the bacterium Vibrio cholera causes massive diarrhea by interfering with such a pathway. A toxin from this bacterium enters intestinal cells and chemically modifies G proteins. Once modified, the G proteins can no longer cleave GTP into GDP, What would you expect to see with the intestinal cells of a person with cholera?

The G proteins remain activated and continually activate adenylyl cyclase.

For the experiment shown in Figure 12.6, which answer best describes what the prediction would be if chromosome movement were based on microtubule shortening at the spindle pole?

The darkened section will move toward the spindle pole but the distance between chromosomes and the darkened section will remain constant.

Select the false statement about the G protein hormone receptor system

The hormone is a ligand for G protein

How can a hormone that is present in very small quantities within the bloodstream elicit such a large response within a cell?

The message from the hormone is amplified many times within the cell.

Which statement about the daughter cells following mitosis and cytokinesis is correct?

They are genetically identical with each other and with the parent cell.

The drug cytochalasin B blocks the function of actin. Which of the following aspects of the cell cycle would be most disrupted by cytochalasin B?

cleavage furrow formation and cytokinesis

The most abundant protein found in the extracellular matrix of animal cells is _____.

collagen

The division of the cytoplasm following mitosis is called _____.

cytokinesis

Which of the following characteristics determines when the refractory period ends?

how long it takes for the voltage-gated Na+ channels to REACTIVATE at the end of an action potential

In which mitotic phase do the chromosomes condense and does the mitotic spindle begin to form?

prophase