week 6 - part 2

Question 1

Name the 4 phases of the cell cycle

Answer 1

GSGM
1. G1, cell growth - has a checkpoint
2. Replication
3. G2, pause - has a checkpoint
4. Mitosis

Question 2

Why does G1+G2 have a checkpoint?

Answer 2

To see if the cell is the right size, damaged or correctly replicated

Question 3

How does the splitting of the cell (mitosis) occur?

Answer 3

an enzyme called MPF

Question 4

Name the 6 stages in mitosis

Answer 4

PPMATC
1. Prophase
2. Prometaphase
3. Metaphase
(m phase)
4. Anaphase
5. Telophase
6 cytokenesis

Question 5

Prophase

Answer 5

organization of chromosome, spindle assembly (the long lines)

Question 6

Prometaphase

Answer 6

Nuclear envelope (surrounds the chromosome) breaks, chromosomes attach to spindle

Question 7

Metaphase

Answer 7

Chromosomes line up at the equator

Question 8

Anaphase

Answer 8

Chromosomes split apart, spindles move away from each other

Question 9

Telophase

Answer 9

New nuclei form, cytokinesis begins

Question 10

Cytokinesis

Answer 10

Cleavage in the middle, mitosis begins

Question 11

Why is the cytoskeleton important in cell division?

Answer 11

Spindle ensure each cell gets the same copy, actin filaments split the cell (contractile ring), Nuclear lamina breaks down and reassembles nucleus

Question 12

Meiosis

Answer 12

Cell division for sexual reproduction, a cell divides twice then divides twice again, reducing chromosome no. to ensure each cell has the correct no. of cells, chromosomes pair

Question 13

M Phase

Answer 13

Nucleus + Cytoplasm divide, 2 daughter cells produced

Question 14

S phase

Answer 14

DNA is produced/ replicated

Question 15

g1

Answer 15

between end of cytokinesis and dna production

Question 16

g2

Answer 16

between end of dna synthesis and beginning of mitosis

Question 17

What is the cell cycle control system

Answer 17

A network of proteins to ensure all dna is replicated occurs in a set order

Question 18

what does the control cycle depend on?

Answer 18

proteins called cdks

Question 19

What is cylin?

Answer 19

Protein in the cell cycle, controls progression of the cycle by binding to cdks, conc rises and falls at different stages

Question 20

how does cylin-cdk trigger different stages of the cell cycle?

Answer 20

the kinase activity increases at different stages of the cycle

Question 21

What does M-cdk do?

Answer 21

drives entry for mitosis

Question 22

Cohesins

Answer 22

Ring shaped protein; organises interphase proteins into large chromatin loops

Question 23

Contractile ring

Answer 23

Myosin+Actin filaments pinching a cell in two

Question 24

Apoptosis

Answer 24

A form of cell suicide