1.5: Protein control of cell division

Question 1

One type of cytoskeleton protein fibre. Hollow cylinders made of the protein tubulin subunits.

Answer 1

Microtubules.

Question 2

Functions of the cytoskeleton.

Answer 2

Cell shape OR Mechanical support OR Organelle attachment OR Movement of vesicles OR Remodelled to form spindle fibre.

Question 3

Polymerisation (lengthens) and depolymerisation (shortens) of microtubules to give the cytoskeleton its dynamic propeties. Also builds the spidnle from tubulin subunits.

Answer 3

Microtubule organising centre (MTOC) OR Centrosome.

Question 4

Results from an uncontrolled reduction in the rate of cell cycle.

Answer 4

Degenerative disease.

Question 5

Abnormal mass of cells produced by an uncontrolled increase in the rate fo the cell cycle.

Answer 5

Tumor

Question 6

A normal gene involved in the control of cell growth which can mutate to form a tumor-promoting oncogene.

Answer 6

Proto-oncogene.

Question 7

Sequence of the cell cycle.

Answer 7

G1, S, G2, M then Cytokinesis.

Question 8

Overall name for the stages of the cell cycle that prepare the cell for mitosis.

Answer 8

Interphase.

Question 9

Occurs during the G1 and G2 stages of interphase.

Answer 9

Cell growth.

Question 10

Occurs during the S phase of interphase.

Answer 10

DNA Replication

Question 11

Sequences of the mitosis stages.

Answer 11

Prophase, metaphase, anaphase then telophase.

Question 12

Stage of mitosis when the DNA condenses into chromosomes each consisting of two sister chromatids.

Answer 12

Prophase.

Question 13

Stage of mitosis when the chromosomes attach to the spindle at cell equator (metaphase place).

Answer 13

Metaphase.

Question 14

Stage of mitosis where as spindle microtubules shorten by depolymerisation, sister chromatids are
separated, and the chromosomes are pulled to opposite poles.

Answer 14

Anaphase.

Question 15

Stage of mitosis when chromosones decondense and two nuclei form.

Answer 15

Telophase.

Question 16

Cell cycle stage where the seperation of the two nuclei and cell contents into two daughter cells occurs.

Answer 16

Cytokinesis.

Question 17

Microtubule structure involved in the arrangement of chromosones on the metaphase plate and seperation of sister chromatids.

Answer 17

Spindle

Question 18

Critical points in cell division where “stop” and “go ahead” signals regulate the cycle. They occur in the g1, g2 and M phases of the cell cycle.

Answer 18

Checkpoints.

Question 19

Critical “go ahead”signals required to pass the G1 checkpoint.

Answer 19

Big enough OR No DNA damage OR growth factor arrived.

Question 20

Critical “go ahead” signal required to pass the M checkpoint.

Answer 20

All chromosomes attached to the spindle.

Question 21

Non-dividing state that a cell enters if it does not recieve the “go ahead” signal at the G1 checkpoint.

Answer 21

G0

Question 22

Proteins that acumulate at each stage of the cell cylce and activate cyclin-dependent kinases (CDK) enzymes.

Answer 22

Cyclins

Question 23

Enzymes activated by cyclin proteins. They phosphorylate proteins involved in progressing the cell cycle.

Answer 23

Cyclin-dependant kinases OR Cdks.

Question 24

When sufficient proteins have been phosphorylated the cell moveson to the next stage of the cell cycle. Held at a checkpoint if insufficient.

Answer 24

Threshold of phosphorylation.

Question 25

Tumor suppressor inhibitor of transcription which is phosphorylated by G1 Cdks to allow the synthesis of various proteins required for DNA replication in the S stage.

Answer 25

Retinoblastoma OR Rb

Question 26

Protein activated by DNA damage.

Answer 26

p53

Question 27

Cell processes stimulated by p53 tumor-suppressor protein activation.

Answer 27

DNA repair OR Cell cycle arrest OR Cell death/ Apoptosis.

Question 28

Programmed cell death triggered by signals that may originate within or outith the cell.

Answer 28

Apoptosis

Question 29

Family of protease enzymes that play an essential role in apoptosis by causing cell destruction.

Answer 29

Caspases

Question 30

External death signal that triggers apoptosis.

Answer 30

Death signal from lymphocyte OR Growth factor absence

Question 31

Internal death signal that trigers apoptosis.

Answer 31

Irreperrable DNA damage OR Activation of p53.

Question 32

Removes cells no longer required duing te development of an organism o during metamorphosis.

Answer 32

Apoptosis.