Chapter 12 Cell Cycle And Mitosis

Question 1

In eukaryotic cells chromosomes are composed of

Answer 1

C) DNA and proteins

Question 2

What is the final result of mitosis in a human

Answer 2

Genetically identical 2n somatic cells

Question 3

If there are 20 duplicated choromosnes in a cell how many centromeres are there

Answer 3

20

Question 4

The first gap in the cell cycle (G1) corresponds to

Answer 4

A) normal growth and cell function

Question 5

The microtubule-organising center found in animal cells is an identifiable structure present during all phases of the cycle specifically it is known as the

Answer 5

Centrosome

Question 6

The mitotic spindle is a microtubular structure that is involved in ________.

Answer 6

D) separation of sister chromatids

Question 7

Metaphase is characterised by ________.

Answer 7

A) aligning of chromosomes on the equator

Question 8

Kinetochore microtubules assist in the process of splitting centromeres by ________.

Answer 8

B) creating tension by pulling toward opposite poles

Question 9

How is plant cell cytokinesis different from animal cell cytokinesis?

Answer 9

B) Plant cells deposit vesicles containing cell-wall building blocks on the metaphase plate; animal cells form a cleavage furrow.

Question 10

FtsZ is a bacterial cytoskeletal protein that forms a contractile ring involved in bacterial cytokinesis. Its function is analogous to ________.

Answer 10

A) the cleavage furrow of eukaryotic animal cells

Question 11

t which phase are centrioles beginning to move apart in animal cells?

Answer 11

D) prophase

Question 12

Which of the following are primarily responsible for cytokinesis in plant cells but not in animal cells?

Answer 12

B) Golgi-derived vesicles

Question 13

The beginning of anaphase is indicated by which of the following?

Answer 13

C) Cohesin is cleaved enzymatically.

Question 14

During which phase of mitosis do the chromatids become chromosomes?

Answer 14

B) anaphase

Question 15

A cleavage furrow is ________.

Answer 15

C) a groove in the plasma membrane between daughter nuclei

Question 16

Several organisms, primarily protists, have what are called intermediate mitotic organisation. These protists are intermediate in what sense?

Answer 16

C) They maintain a nuclear envelope during division.

Question 17

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

Answer 17

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

Question 18

Which of the following does NOT occur during mitosis?

Answer 18

B) replication of the DNA

Question 19

Motor proteins require which of the following to function in the movement of chromosomes toward the poles of the mitotic spindle?

Answer 19

C) ATP as an energy source

Question 20

MPF is a dimer consisting of ________.

Answer 20

D) cyclin and a cyclin-dependent kinase

Question 21

Cyclin-dependent kinase (Cdk) is ________.

Answer 21

D) an enzyme that attaches phosphate groups to other proteins

Question 22

The M-phase checkpoint ensures that all chromosomes are attached to the mitotic spindle. If this does not happen, cells would most likely be arrested in ________.

Answer 22

D) metaphase

Question 23

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

Answer 23

A) PDGF

Question 24

Which of the following is a protein maintained at steady levels throughout the cell cycle that requires cyclin to become catalytically active?

Answer 24

D) Cdk

Question 25

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

Answer 25

B) MPF

Question 26

The cyclin component of MPF is destroyed toward the end of which phase?

Answer 26

D) M

Question 27

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

Answer 27

B) As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing.

Question 28

Besides the ability of some cancer cells to overproliferate, what else could logically result in a tumour?

Answer 28

B) lack of appropriate cell death

Question 29

Anchorage dependence of animal cells in vitro or in vivo depends on which of the following?

Answer 29

B) response of the cell cycle controls to signals from the plasma membrane

Question 30

Cells from advanced malignant tumours often have very abnormal chromosomes and an abnormal number of chromosomes. What might explain the association between malignant tumours and chromosomal abnormalities?

Answer 30

C) Cell cycle checkpoints are not in place to stop cells with chromosome abnormalities.