Module 8- Cancer

Question 1

3 marks

The KRAS gene codes for a protein called K-Ras. The protein relays signals from outside a cell to a cell’s nucleus, stimulating cell division. An alteration in the KRAS gene produces an oncogene which can cause a tumour to develop.
Suggest and explain how an alteration in the KRAS gene can cause a tumour to develop.

Answer 1

1. Mutation in KRAS gene
2. Change in signalling protein
3. Results in uncontrollable cell division

Question 2

3 marks

Describe how alterations to tumour suppressor genes can lead to the development of tumours.

Answer 2

1. Increased methylation of tumour suppressor genes
2. Mutation in tumour suppressor genes
3. Tumour suppressor genes are not transcribed/expressed
   OR
   Amino acid sequence/primary structure altered
4. Results in uncontrollable cell division

Question 3

Define metastasis

Answer 3

Cells can break off these tumours and spread to other parts of the body through the bloodstream or lymphatic system

Question 4

Define malignant tumour

Answer 4

Uncontrolled mitosis, unspecialised cells, metastasis

Question 5

Define oncogene

Answer 5

Could cause expression of excessive growth factor protein or distortion of receptor protein= uncontrolled mitosis

Question 6

Define tumour suppressor gene

Answer 6

Could cause expression of proteins that cause apoptosis (P53)= death of tumour cells