question

All of the following statements are true except:

answer

The motic spindles in prokaryotic cells are composed of microtubules

question

The centromere is a region in which

answer

Chromatids are attached to one another

question

Two centromeres are arranged at opposite poles of the cell

answer

Prometaphase

question

Centrioles begin to move apart in animal cells.

answer

Prophase

question

This is longest of the mitotic stages.

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Phophase

question

Centromeres uncouple, sister chromatids are seperated, and the two new chromosomes move to opposite poles of the cell

answer

Anaphase

question

If 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?

answer

Metaphase

question

A cell containing 92 chromatids at metaphase of mitosis would, at its completion, produce two nuclei containing how many chromosomes?

answer

46

question

All of the following occur during prometaphase of mitosis in animal cells except

answer

Chromosomes are duplicated

question

If there are 20 centromeress in a cell, how many chromosomes are there?

answer

20

question

Of the following, the best conclusion concerning the difference between the S phase for beta and grama is that

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gamma contains more DNA than beta

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The best conclusion concering delta is that the cells

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Containonly one chromosomethat is very short

question

The S phase was measured by

answer

determining the start and stop of increased DNA in the cells

question

Where do the microtubules of the spindle orginate during mitosis in both plant and animal cells?

answer

Centrosome

question

All of the following occur during mitosis except

answer

The synthesis of DNA

question

if a cell has 8 chromosomes at metaphase of mitosis, how many chromosomes will it have during anaphase?

answer

16

question

Cytokinesis usually, but not always, follows mitosis. If a cell composed mitosis but not cytokinesis, what would be the result?

answer

a cell with 2 nuclei

question

reguarding mitosis and cytokinesis, one difference between higher plants and animals is that in plants

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a cell plate begins to form at telophase, whereas in animals a clevage furrow is initiated at that stage

question

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

answer

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

question

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 that?

answer

a plant cell unergoing cytokinesis

question

Taxol is an anticancer drug extracted from the pacific yew tree. In animal cells, taxol disrupts mictrotubles and acclerating their assembly from the protein precursor, tubulin. Suprisingly this stops mitosis. Specifically taxol must affect

answer

The fibers of the mitotic spindle

question

Which of the following is primarily responsible for cytokinesis in plant cells?

answer

Golgi- derived vesicles

question

Which of the following organisms does not reproduce cells by mitosis and cytokinesis?

answer

bacterium

question

During which phase of mitosis do we find chromosomes composed of 2 chromatids?

answer

from G2 of interphase through metaphase

question

Which of the following is not true of bacterial chromosome?

answer

Its centromeres uncouple during replication

question

I which group of eukaryotic organisms does the nuclear envelope remain intact during mitosis?

answer

dinoflagellates and diatoms

question

Movement of the chromosomes during anaphase would be most affected by a drug that

answer

Prevented shortening of microtubles

question

If mammalian cells recieve a go-ahead signal at the G1 checkpoint, they will

answer

complete the cycle and divide

question

Cells that are in a nonividing state are in which phase?

answer

G0

question

Measurements of the amount of DNA per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per nucleus. In which stage of the cell cycle was the nucleus with 6 picograms of DNA?

answer

G2

question

What causes the rhythmic change in cyclin concentration in the cell cycle?

answer

Its destruction by an enzyme phosphorylated by MPF

question

released by platelets in the vicinity of an injury

answer

PDGF

question

enzymes that activate or inactivate other proteins by phosphorylating them

answer

Protain kinase

question

fibroblasts have receptors fro this substance on their plasma membranes

answer

PDGF

question

a protein synthesized through the cell cycle that associates with a kiase to form active enzymes

answer

cyclin

question

triggers the cell's passage past the G2 checkpoint into mitosis

answer

MPF

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the "restriction point" occurs here

answer

G1

question

nerve and muscle cells are in this phase

answer

G0

question

the shortest part of cell cycle

answer

M

question

DNA is replicated at this time of the cell cycle

answer

Protein Kinase

question

Cyclin is destroyed toward the end of this phase

answer

M

question

What are enzymes called that control the activites of other proteins by phosphorylating them?

answer

kinase

question

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 woul have ____ picograms at the end of the S phase and ________ picograms at the end of G2

answer

16 ... 16

question

As the cell progresses through prophase and into metaphase, ehat happens to the active anaphase-promoting complex proteins?

answer

they increase sharply once all the chromosomes are lined up in metaphase

question

what triggers the seperation of chromatids during mitosis?

answer

activation of an anaphase-promoting complex

question

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

answer

cyclins

question

THe MPF protein complex turns itself off by

answer

activating an enzyme that destroys cyclin

question

recent research has indicated that cancer cells

answer

transform normal cells by altering genes involved in the control of mitosis

question

a mutation results in a cell that no longer produces a normal protein kinase for the M phase checkpoint. Which of the following would likely be the immediate result of this mutation?

answer

the cell would undergo normal mitosis, but fail to enter the next G1

question

Density-dependent inhibition is explained by which of the following?

answer

as the cells become more numerous, the amount of required growth factors and nutrients per cell becomes insufficient to allow for cell growth

question

Which of the following is true concering cancer cells?

answer

they do not exhibit density-dependent inhibition when growing in culture,when they stop dividing they do so at random points in the cell cycle, and they have escaped from cell cycle controls

Chapter 12; Cell Cycle – Flashcards

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