BIOC192 Lecture 18 - What are Dominant and Recessive Mutations?

Question 1

what is cancer?

Answer 1

result of an accumulation of mutations that make the cells to have disturbed division and increased cell division.

Question 2

what are most of the cancer cell mutations associated with?

Answer 2

associated with DNA replication

Question 3

why does the incidence of cancer increase with age?

Answer 3

the more times a cell divides, the more likely it is to gain a mutation

Question 4

where does the mutations occur in the cell leading to cancer?

Answer 4

somatic cells

Question 5

what are the 2 types of mutations that cause cancer?

Answer 5

1) spontaneous mutations (occur by chance)

2) exposure to a mutagen (also called carcinogen)

Question 6

what are the 2 types of genes that cause cancer when mutated?

Answer 6

1) tumor suppressor genes

2) onco-genes

Question 7

what are tumour suppressor genes?

Answer 7

encode proteins that normally prevent uncontrolled cell growth e.g:

• proteins that inhibit cell division
• prevent other mutations (DNA repair enzymes)
• often referred to as the ‘brake pedal’

Question 8

what is the result of the lack of tumour suppressor genes?

Answer 8

lack of these genes can stimulate cell growth - i.e recessive mutations promote cancer

Question 9

what are onco-genes?

Answer 9

encode proteins that promote cell growth e.g:

• proteins that stimulate cell division
• cancer mutations increase the activity of these genes
• dominant mutations promote cancer

Question 10

why does it require a companion of both the tumour suppressor genes and the Onco-genes to cause cancer?

Answer 10

because the tutor-suppressor genes are known as the brake pedal they can no matter what stop the Onco-genes known as the accelerator therefore it requires a combination of both the dominant and recessive mutations to promote cancer

Question 11

what is the function of tumour suppressor genes?

Answer 11

mutations that decrease gene activity that cause cancer

Question 12

what is the process of the tumour suppressor cell decreases gene activity?

Answer 12

this cell is prevented from undergoing cell division due to inactivation of E2F transcription factor

Question 13

what is the function of Onco-genes?

Answer 13

mutations that increase gene activity that cause cancer

Question 14

what is a proto-oncogene?

Answer 14

a normal gene that when mutated can promote uncontrolled cell growth

Question 15

what are 2 ways to increase the activity of a gene through mutations?

Answer 15

1) mutations that increase transcription

2) mutations that increase protein acuity

Question 16

what is the result of a mutation increasing protein activity?

Answer 16

the protein produced is always active or is not degraded

Question 17

what are the 3 treatments for cancer?

Answer 17

1) surgery (remove cancer cells)
2) radiation therapy (targeted radiation treatment to kill cancer cells)
3) chemotherapy (uses drugs that target dividing cells as cancer cells grow and divide rapidly - but it also affects normal cells)

Question 18

what is targeted cancer therapy?

Answer 18

drugs that target changes in cancer cells that allow them to grow and divide