20.5 gene expression and cancer

Question 1

compare the size of a benign tumour to a malignant tumour

Answer 1

both grow to a large size

Question 2

compare the speed to growth in a benign tumour to a malignant tumour

Answer 2

benign-> grows slowly

malignant-> grows quickly

Question 3

compare the state of differentiation in benign tumours to malignant tumours

Answer 3

benign-> specialised

malignant-> unspecialised

Question 4

what is metastasis?

Answer 4

process where tumours spread to other parts of the body forming secondary tumours

Question 5

compare the adhesion of the cells in benign tumours and malignant tumours

Answer 5

benign-> adhesion molecule produced so stick together

malignant-> no adhesion molecules so don’t stick together

Question 6

compare the presence of a capsule in benign tumours and malignant tumours

Answer 6

benign-> capsule

malignant-> no capsule

Question 7

compare the threat to life benign tumours and malignant tumours have

Answer 7

benign-> not life threatening

malignant-> life threatening

Question 8

compare the effect of the body benign and malignant tumours have

Answer 8

benign-> localised

malignant-> systemic

Question 9

how are benign tumours removed?

Answer 9

surgery

Question 10

how are malignant tumours removed?

Answer 10

radiotherapy, chemotherapy, surgery

Question 11

compare how frequent benign tumours and malignant tumours appear after treatment

Answer 11

benign-> rarely

malignant-> more frequently

Question 12

malignant tumour definition

Answer 12

cancerous tumour

Question 13

benign tumour definition

Answer 13

non- cancerous tumour

Question 14

what are the 2 main type of genes that play a role in cancer?

Answer 14

• oncogenes

- tumour suppressor genes

Question 15

what are oncogenes?

Answer 15

mutated proto-oncogenes

Question 16

what are proto-oncogenes?

Answer 16

genes that stimulate a cell to divide when growth factors attach to a protein cells on its cell surface membrane

Question 17

what happens to proto- oncogenes when growth factors attach to them?

Answer 17

genes are activated which cause DNA to replicate and the cell divides

Question 18

why are oncogenes genes permanently switched on?

Answer 18

• receptor protein can be permanently activated, so that cell division is switched on even if the growth factor is absent
• oncogenes code for a growth factor that is then produced in excessive amounts causing excessive division of cells

Question 19

what are tumour suppressor genes?

Answer 19

genes that slow down cell division, repair mistakes in DNA and ‘tell’ cells to apoptose