3.4.8

Question 1

2 major causes of spontaneous mutations

Answer 1

radiation

chemical mutagens

Question 2

mutagens

Answer 2

any agent that cause/increase the frequency of mutations by triggering changes in the genetic material of an organism

Question 3

carcinogens

Answer 3

mutagens that lead to mutations causing cancer

Question 4

how humans exposed to mutagens

Answer 4

radiation in environment (UV radiation from sun)

chemical mutagens

cigarette smoke

food (nitrites, e.g. in cured meat)

Question 5

radiation

Answer 5

occurs when energy (in form of waves/particles) emitted

Question 6

effects of low energy radiation

Answer 6

harmless=lack the energy to break chemical bonds

example: microwave

Question 7

higher energy radiation (ionising radiation)

Answer 7

can break bonds between atoms leading to mutations (e.g. x-ray, alpha/b/g radiation from radioactive elements

Question 8

mutation

Answer 8

change in an organisms genetic code

Question 9

gene mutation

Answer 9

change in the nucleotide sequence of a section of DNA coding for a particular sequence

new alleles are created by gene mutation

Question 10

iodine-131

Answer 10

may increase the mutation rate in thyroid gland and cause cancer if incorporated to thyroid hormones

Question 11

ARS (Acute Radiation Syndrome)

Answer 11

when a person exposed to a large dose of ionising radiation

lower doses=nausea, headache
higher dose=seizures, fever, death

people who survived ARS=higher risk of cancer (leukemia) and number of mutations