1.5(a) - Protein control of cell division

Question 1

What is the cytoskeleton?

Answer 1

The cytoskeleton gives mechanical support and shape to cells

Question 2

What are microtubules?

Answer 2

Hollow cylinders composed of tubulin

Question 3

What do microtubules do/what is their function?

Answer 3

Microtubules control the movement of membrane bound organelles and chromosomes within the cell

Question 4

What are the two phases in the cell cycle?

Answer 4

1. The mitotic phase
2. The interphase

Question 5

What are the 3 phases within the interphase?

Answer 5

1. G1 phase is the (first) growth stage
2. S phase is when DNA replication takes place
   3.G2 phase is a further growth phase

Question 6

What two processes does the mitotic phase involve?

Answer 6

Mitosis and cytokinesis

Question 7

What is cytokinesis?

Answer 7

When the cell is divided into two daughter cells

Question 8

Mitosis steps

SM = Spindle microtubules

Answer 8

1. Prohpase - DNA condenses into chromosmes (2 sister chromatids). Nuclear membrane breaksdown and SM extend form the MTOC by polymerisation and attach to choromosomes via kinetorches
2. Metaphase - Chromosomes are aligned at the metaphase plate
3. Anaphase - Spindle microtubules shorten by depolymeristaion, sister chromatids are seperated and chromosomes pulled to opposite poles
4. Telephase - Chromosomes decondense and nuclear membranes are formed around them