Cell Cycle & Mitosis

Question 1

4 cell cycle phases

Answer 1

M
G1
S
G2

Question 2

3 control points

Answer 2

Enter S
Enter M
Exit M

Question 3

cdc genes

Answer 3

crucial for cells cycle control, code for protein needed during cell cycle

Question 4

cdc gene mutations

Answer 4

cause cells to arrest at specific points during the cell cycle

Question 5

cdc mutants are conditional

Answer 5

usually temp. sensitive

Question 6

cell cycle control is _____ throughout eukaryotes

Answer 6

conserved

Question 7

mitosis promoting factor (MPF)

Answer 7

• cell cycle control complex able to cause M phase in nuclei

- complex between 34kD serine/threonine protein kinase, p34cdc2, and 45kD substrate (Xenopus B-type cyclin)

Question 8

cdc2

Answer 8

master regulator which is a cyclin dependent kinase (Cdk)

Question 9

cdc2 inhibited & activated by:

Answer 9

inhibited: wee1
activated: cdc25

Question 10

cyclins are ____ and _____ each cell cycle

Answer 10

made

destroyed

Question 11

Cdk regulation ensures:

Answer 11

ordered progression through the cell cycle

Question 12

Cdk only active when:

Answer 12

tightly bound to cyclin

Question 13

2 main groups of cyclin/cdk complexes

Answer 13

• G1/S

- G2/M

Question 14

licensing prevents:

Answer 14

re-replication

Question 15

each cyclin/cdk complex _____ a different set of substrate proteins

Answer 15

phosphorylates

Question 16

When are cdks fully activated?

Answer 16

when Cdk-activating kinase phosphorylates cdk near its’ active site

Question 17

4 control points

Answer 17

1. cell growth
2. favourable environment?
3. DNA damage?
4. replication problems?

Question 18

4 preparation stages for mitosis:

Answer 18

1. chromosome duplication
2. cohesin holds together sister chromatids
3. centrosome duplication
4. MPF activation

Question 19

Prophase (2)

Answer 19

• chromosomes condense

- mitotic spindle assembles

Question 20

Prometaphase (2)

Answer 20

• nuclear envelope breakdown

- chromosomes attach to MTs

Question 21

Metaphase (2)

Answer 21

• chromosomes aligned at equator

- paired kinetochore MTs on each chromosome attach to opposite poles of spindle

Question 22

Anaphase (3)

Answer 22

• sister chromatids separate
• spindle poles move apart
• kinetochore MTs get shorter

Question 23

Telophase (3)

Answer 23

• 2 sets of chromosomes arrive at poles of spindle
• new nuclear envelope reassembles
• contractile ring begins to form

Question 24

Cytokinesis

Answer 24

• division of cytoplasm with help of actin/myosin contractile ring

Question 25

MPF controls entry into____ by ______ of key targets

Answer 25

mitosis

phosphorylation

Question 26

2 things required for higher order chromosome structure

Answer 26

cohesin

condensin

Question 27

cohesin and condensin together make:

Answer 27

structural maintenance complexes (SMC)

Question 28

MTs are ____ during mitosis and constantly _____ & ____

Answer 28

dynamic
shrink
elongate

Question 29

phosphorylation ______ nuclear envelope, when M-Cdk is ______

Answer 29

breaks down

active

Question 30

M-Cdk inactivated at _____ so new nuclear envelope re-assembles

Answer 30

anaphase

Question 31

3 types of MTs during mitosis

Answer 31

aster
kinetochore
interpolar

Question 32

kinetochores attach chromatids to:

Answer 32

microtubules

Question 33

spindle assembly checkpoint monitors:

Answer 33

1. occupancy of kinetochores

2. tension

Question 34

spindle assembly checkpoints acts through:

Answer 34

APC and MAD proteins

Question 35

MAD proteins at unattached kinetochores inhibit:

Answer 35

APC

Question 36

metaphase to anaphase transition

Answer 36

cohesin complex dissociates with help of active separase

Question 37

separase is inhibited by:

Answer 37

securin

Question 38

anaphase A

anaphase B

Answer 38

A - chromosomes pulled poleward

B - poles are pulled and pushed apart

Question 39

APC promotes:

Answer 39

1. destruction of cyclin

2. mitotic exit

Question 40

active APC causes _______ and ______ of securin

Answer 40

ubiquitylation

degradation