Cell cycle

Question 1

What are the 5 parts of cell division?

Answer 1

G1 phase
S phase
G2 phase
mitosis/ M phase
cytokinesis

Question 2

What do G1, S and G2 phases collectively make up?

Answer 2

Interphase

Question 3

What are the 5 parts that make up mitosis?

Answer 3

prophase
prometaphase
metaphase
anaphase
telophase

Question 4

What happens in G1?

Answer 4

The cell is gathering material and preparing for protein synthesis and DNA replication:

1) the cell increases in size
2) increases the number of organelles such as mitochondria and ribosomes
3) it is cleared by checkpoint proteins before it can move onto the S phase

Question 5

What happens in S?

Answer 5

1) the DNA replicates - the amount of DNA doubles

2) Histones are produced

Question 6

What happens in G2?

Answer 6

1) There is rapid cells growth

2) DNA that has been replicated is checked to ensure there is no damage or mutations with the chromosomes.
(mainly regulated by the tumour suppressor protein - P53, if damages found then repair or apoptosis is carried out)

Question 7

What is mitosis is also known as?

Answer 7

karyokinesis

Question 8

What is the overall function that happens in the mitosis/ karyokinesis?

Answer 8

nuclear division

cytoplasmic divison (cytokinesis)

Question 9

What happens in prophase?

Answer 9

1) nuclear membrane and nucleolus disintegrates

2) centrosomes duplicate and move to opposite ends of the cell

3) chromosomes become condensed

(centrosomes organise the microtubules that produce the mitotic spindles)

Question 10

what happens in prometaphase?

Answer 10

1) chromosomes line up in the centre of the cell (via centromere) at right angles to their centromere.

2) spindle fibres join to their kinetochore

Question 11

what happens in metaphase?

Answer 11

chromosomes attach to the metaphase plate of the mitotic spindle

Question 12

what happens in anaphase?

Answer 12

centromeres are pulled part by the spindle fibres and spindle fibres are pulled to opposite pole

Question 13

what happens in telophase?

Answer 13

1) spindle fibres disintegrate

2) nuclear membrane reforms around the chromosomes at the opposite poles

Question 14

what happens in cytokinesis?

Answer 14

cytoplasm divides and there are 2 new daughter cells

Question 15

One cause of cancer?

Answer 15

mutation of p53 = uncontrollable cell division

Question 16

what makes up a chromosome?

Answer 16

2 sister chromatid joined together by a centromere.