Mitosis

Question 1

Prophrase

Answer 1

Chromosome condense (thicker/shorter)
= 2 sister chromatids, joined by centromeres
-nuclear envelope breaks down
-centrioles begin to pull apart move to opposite poles forming the spindle

Question 2

Metaphrase

Answer 2

Chromosomes align along the equator of the cell

-spindle fibre attach to chromosome by centromeres

Question 3

Anaphase

Answer 3

Chromatids from each pair are pulled, centromeres first towards opposite poles of the cell
Spindle fibre contract —> pull chromatids to opposite poles of the cell by the overlapping fibre contract and cause the movement of the chromatids supplied by ATP

Centromeres divides

Question 4

Telephrase (two)

Answer 4

Chromosomes uncoil (longer/thinner) and separate becoming less dense

Nuclear envelope reforms = 2 nuclei

Spindle fibres & centrioles break down

Question 5

Interphrase

Answer 5

Growing
Replicating DNA
Carry out normal cellular activities

Question 6

G1

Answer 6

PREPARATION 
-organelle replicates
- increase cell size
-protein synthesis
—> respiration 

A signal is received telling the cells to divide again

This phrase of the interphase stage of the cell cycle is called the S phrase (synthesis of DNA) (relatively short)
Chromosomes replicate and become doubled stranded chromatids

• cells make the RNA, enzymes and other proteins required for growth during the G1 phase

Question 7

G2

Answer 7

The cell continues to grow and the new DNA that has been synthesised is checked and any error are usually repaired

Question 8

What makes up interphase

Answer 8

G1+ S+ G2

Question 9

Mitosis

Answer 9

Nucleus is actively dividing

Question 10

Cytokinesis

Answer 10

New cell divides in the cytoplasm

Question 11

Checkpoints

Answer 11

G1 checkpoint - cell size? DNA damage?

If not then goes into G0 ( cell leaves the cell cycle)

G2 checkpoint - DNA replication error

Question 12

What happens in G0

Answer 12

Differentiate, (muscle cell)
die,
enter senescence (where they stop dividing) (ageing)

Question 13

Why does mitosis happen

Answer 13

Repair
Growth
Asexual reproduction