Mitosis

Question 1

What stage of the cell cycle does all DNA unravel?

Answer 1

Interphase

Question 2

Which stage is being disrupted if vincristine (drug to treat cancer) prevents the formation of spindle fibres within the nuclei of cells?

Answer 2

Mitosis

Question 3

Within the required practical. Why do you soak root tips in hydraulic acid 2 marks

Answer 3

1. To break down links between cells/cell walls
   Which separates cells/cell walls
   OR
   To break down/hydrolyse cellulose/cell wall;
2. Allowing the stain to pass/diffuse into the cells
3. To stop mitosis;

Question 4

Human papilloma virus infects cells that are no longer dividing. The human papilloma virus genome contains genes that code for proteins that cause human cells to restart their cell cycles.

Human papilloma virus infection can cause cancer.

Explain why.

1 mark

Answer 4

Uncontrolled cell cycle / division / mitosis