Mutations

Question 1

what is a mutation

Answer 1

a permanent change in sequence of base pairs

Question 2

what causes mutations

Answer 2

1. mistakes which escape proof-reading function
2. changes in the environment - toxins in food, radiation, chemical exposure

Question 3

what are germ cells

Answer 3

reproduction, sperm or egg cells

Question 4

what do mutations in germ cells cause

Answer 4

1. can lead to inherited diseases
2. mutation in a single base out of three can cause loss in protein function and decrease fitness
3. all children of sufferer will carry mutation

Question 5

what are somatic cells

Answer 5

all other cells in the body

Question 6

what does somatic cell mutations cause

Answer 6

1. this mutation gives a rise to cancer
2. mutations accumulate in cells with age
3. more than one gene needs to be mutated a single cell before it is cancerous

Question 7

what are carcinogens

Answer 7

all agents cause cancer

Question 8

what can carcinogens also cause

Answer 8

mutations. (mutagens x-rays and chemicals)

Question 9

what are chemical carcinogens either

Answer 9

1. direct acting- few directly attack DNA
2. Indirect- largest group, activated in detoxification

Question 10

what causes detoxification

Answer 10

cytochrome P-450, ENZYMES IN LIVER ADD CHEMICAL GROUPS to allow chemical breakdown

Question 11

what is deamination

Answer 11

the loss of an amino group from cytosine and C->T change

Question 12

what is deprivation

Answer 12

loss of base pair

Question 13

how are thymine dimers formed

Answer 13

result from cross linking 2 adjacent thymine by UV Light