6.1.1 mutations and variation

Question 1

define mutation

Answer 1

a change in the DNA base sequence of an organism

Question 2

what are the 2 types of mutations?

Answer 2

1. chromosomal
2. gene

Question 3

what are chromosome mutations?

Answer 3

change in the number or structure of whole chromosomes

Question 4

what are gene mutations?

Answer 4

change to the sequence of nucleotides in DNA molecules

Question 5

what happens to mutations that occur during the formation of gametes?

Answer 5

the mutations will be passed onto the next generation

Question 6

what are the 2 types of gene mutations?

Answer 6

point and indel

Question 7

what is a point mutation?

Answer 7

where one base is substituted for another

Question 8

what are the 3 types of point mutations?

Answer 8

1. nonsense
2. mis-sense
3. silent

Question 9

what is a nonsense point mutation?

Answer 9

the change results in a stop codon

Question 10

what is a mis-sense point mutation?

Answer 10

a different amino acid is coded for

Question 11

what is a silent point mutation?

Answer 11

a different base occurs in the triplet but the same amino acid is coded for

Question 12

what are indel mutations?

Answer 12

an extra base is added or deleted leading to a frameshift

Question 13

what is a mutagen?

Answer 13

a chemical, physical or biological agent which causes a mutation

Question 14

give examples of some mutagens?

Answer 14

ionising radiation, chemicals etc

Question 15

what is a neutral mutation?

Answer 15

it has no effect on the organism

Question 16

what is a beneficial mutation?

Answer 16

it has an advantageous effect on organism so increases it chance of survival

Question 17

what is a harmful mutation?

Answer 17

it has a disadvantageous effect on the organism so it decreases its chance of survival