Cell Cycle

Question 1

What happens during interphase?

Answer 1

DNA replication, organelle duplication and protein synthesis

Question 2

What are the stages of the cell cycle?

Answer 2

Interphase, G0, G1, S, G2 and M (mitosis)

Question 3

What happens during the G0 stage?

Answer 3

Cell goes about its normal function.

Question 4

What happens during the G1 stage?

Answer 4

This is the first decision point, which is used to check if mitosis can happen.

Question 5

What happens during the S stage?

Answer 5

DNA synthesis, protein synthesis. duplication of organelles, elongation and capacity increased

Question 6

What happens during G2?

Answer 6

This is the decision point 2, check to see if mitosis can take place.

Question 7

what are the stages of mitosis?

Answer 7

Prophase, prometaphase, metaphase, anaphase, telophase and (cytokinesis)

Question 8

Where do spindle fibres grow from?

Answer 8

Centrosomes

Question 9

What is a kinetocore?

Answer 9

The ‘belt’ which joins sister chromatids around the centromere region.

Question 10

How are the daughter cells separated during mitosis and cytokinesis?

Answer 10

Using a contractile ring, made of actin, which forms a cleavage furrow that eventually splits to become to separate cells.

Question 11

What is checked before anaphase can take place? What signals are used?

Answer 11

That every single chromatid is attached to microtubules, and that these microtubules come from different poles (for sister chromatids). This is checked as unattached kinetochores send signals, such as CENP-E and BUB protein kinases, which must be dissociated before mitosis can continue.

Question 12

What do growth factors do?

Answer 12

Signal cells to go into the next stage of mitosis/cell cycle.

Question 13

What types of changes can growth factor signalling cause?

Answer 13

Metabolic regulation, gene expression and cytoskeleton structure.

Question 14

How does the growth factor signalling cascade work?

Answer 14

Kinase one becomes active after phosphorylation, which then activates the phosphorylation of kinase 2, which then actives the phosphorylation of kinase 3. These are then inactivated by phosphatases. Cyclins also regulate the cascade, regulating at the level of expression, and are degraded when unused, whilst cyclin-dependant kinases are always present but require the binding of cyclins to work.