mutation

Question 1

mutations

Answer 1

changes in DNA which result in no protein or protein being synthesised
- random, spontaneous, rare

Question 2

factors that increase rate of mutation

Answer 2

mutagenic agents

Question 3

2 types of mutagenic agents

Answer 3

chemicals - mustard gas
radiation - uv light, x rays, gamma rays

Question 4

single gene mutation

Answer 4

change in one of the base pairs in DNA sequence of a gene

Question 5

substitution

Answer 5

1 base altered
1 amino acid affected

Question 6

insertion

Answer 6

extra base inserted into DNA
- ‘READING’ codons altered
- causes major changes to structure

Question 7

deletion

Answer 7

base deleted from DNA
- ‘reading’ triplets altered
- amino acids different causing changes to protein

Question 8

frameshift mutations

Answer 8

base removed (deletion) then additional base (inserted) causing amino acids to be changed
- affects structure of protein

Question 9

why are insertion and deletion mutations bad

Answer 9

lead to changes in sequence of amino acids in the protein being synthesised
- causes overall shape which is imp in relation to its function to alter
- may affect shape of active site

Question 10

when do mutations occur

Answer 10

when DNA copying itself in prep for cell division

Question 11

chromosome structure mutations

Answer 11

involves changes to the no or sequence of genes in chromosome
- on a larger scale and have a greater effect that single gene mutations

Question 12

duplication

Answer 12

section of chromosome added from its homologous partner
- break causing 2 sections to separate, section of genes from partner inserted

Question 13

deletion

Answer 13

section of chromosome is removed
- breaks in 2 places section becomes removed or detached
- after deletion - shorter than original chromosome and doesn’t have certain genes

Question 14

inversion

Answer 14

section of chromosomes reversed
- sections breaks in 2 places, detaches, rotates, rejoins

Question 15

translocation

Answer 15

section of chromosome added to another chromosome which isn’t its homologous partner
- break off from original, attach to other

Question 16

mutations are…

Answer 16

only source of new variations, producing new sequences of genes in chromosomes
- have an adverse or lethal effect of organisms

Question 17

gene duplication allows

Answer 17

• potential beneficial mutations to occur
• original gene to still be expressed
• produce normal functioning protein