3.8 The cell cycle

Question 1

Describe how tumours and cancers form (2)

Answer 1

● Mutations in DNA / genes controlling mitosis can lead to uncontrolled cell division
● Tumour formed if this results in mass of abnormal cells
○ Malignant tumour = cancerous, can spread (metastasis)
○ Benign tumour = non-cancerous

Question 2

Suggest how cancer treatments control rate of cell division

Answer 2

● Some disrupt spindle fibre activity / formation
○ So chromosomes can’t attach to spindle by their centromere so no metaphase
○ So chromatids can’t be separated to opposite poles (no anaphase)
○ So prevents / slows mitosis
● Some prevent DNA replication during interphase
○ So can’t make 2 copies of each chromosome (chromatids)
○ So prevents / slows mitosis

Question 3

Define cancer

Answer 3

A group of diseases caused by a growth disorder of cells.
It is the result of damage to the genes that regulate mitosis and the cell cycle.This leads to uncontrollable cell growth

Question 4

What is a malignant tumour

Answer 4

A rapid growing tumour which is more likely to be life threatening as they can spread across the body
Cancerous

Question 5

What is a benign tumour

Answer 5

A slower growing tumour that stayes in one place they are also more compact
Non cancerious

Question 6

How is cancer treated

Answer 6

By blocking a part of the cell cycle (chemotherapy)

Question 7

How does chemotherapy disrupt the cell cycle

Answer 7

Prevents DNA from replicating
Inhibiting the metaphase stage of mitosis by interferring with spindle formation

Question 8

What is the problem with drugs like chemo

Answer 8

It also disrupts the cell cycle of normal cells
Chemo targets the cells that rapidly divide like cancer cells but this also attacks hair cells as they also divide rapidly