Intro

Question 1

Define cancer

Answer 1

Any disorder of cell growth that results in invasion and destruction of surrounding healthy tissues by abnormal cell

Question 2

Two properties of cancerous cell

Answer 2

1. Abnormal cell growth and division

2. Abnormalities in the normal restraints that keep cells from spreading and invading other parts of bodies

Question 3

Cell cycle regulators

1. External signals
2. Internal signals

Answer 3

1. Growth factors
   - > received at cell surface membrane, cause completion of cell cycle
2. Cyclins
   - > increase and decrease as cell cycle continues

Question 4

Cyclically operating molecule include?

Their function?

Answer 4

1. Cyclins: trigger progression

2. Cycling-dependent kinase

Question 5

How does cyclins work?

Answer 5

• trigger progression through cell cycle
• Low conc at start; increases as signals are received to stimulate cell division
• combine with a second class protein (CDK)
• > binding to specific CDK triggers activity of cyclin-CDK complex
• > selectively phosphorylase and activate other proteins

Question 6

What happens when cyclin conc. increases?

Answer 6

• combine with a second class protein (CDK)
• > triggering the activity of cyclin-CDK complex

-CDK complex then selectively phosphorylate and activate other proteins
> bring about changes necessary to advance the cell

Question 7

Function of cyclin-CDK complex (MPF)?

Answer 7

=maturation promoting factor

-trigger cell’s passage past the G2 checkpoint into M phase (prophase)

-activates a protein breakdown process that breakdown its cyclins
=> reducing MPF activity

Question 8

Describe the formation of tumour?

Answer 8

Dsyregulation of cyclin and CDK interaction will result in uncontrolled cell division

Question 9

What happens during anaphase?

Answer 9

MPF switches itself off by initiating a process that leads to destruction of its own cyclin