unit 1 key area 6

Question 1

what is a mutation

Answer 1

changes in the DNA that can result in no protein or an altered protein being synthesised

Question 2

what are the two types of mutations

Answer 2

gene and chromosome

Question 3

what is single gene mutations

Answer 3

single gene mutation involves the alteration of a DNA nucleotide sequence

Question 4

what are single gene mutations a result of

Answer 4

substitution insertion deletion

Question 5

what is substitution

Answer 5

one base/nucleotide is swapped for another

Question 6

what does substitution alter

Answer 6

one codon which alters one amino acid

Question 7

what are the two types of substitution

Answer 7

missense and nonsense

Question 8

what is missense substitution

Answer 8

result in one amino acid being changed for another

Question 9

what does missense substitution result in

Answer 9

non-functional protein or may have little effect on the protein

Question 10

what is nonsense substitution

Answer 10

results in a premature stop codon being produced

Question 11

what does nonsense substitution result in

Answer 11

a shorter protein being formed

Question 12

what is a splice site mutation

Answer 12

result in some introns being retained and/or some exons not being included in the mature transcript

Question 13

what is insertion

Answer 13

extra nucleotide added into sequence

Question 14

what is deletion

Answer 14

nucleotide is removed from sequence

Question 15

what do insertion and deletion both result in

Answer 15

a frameshift mutation

Question 16

what is a frame shift mutation

Answer 16

every codon after the mutation is altered therefore every amino acid after is changed

Question 17

what effect does a frameshift mutation have on the protein produced

Answer 17

major change to proteins structure

Question 18

what is a chromosome mutation

Answer 18

involves a change in the structure or number of chromosomes

Question 19

what are the 4 types of chromosome mutation

Answer 19

translocation inversion deletion duplication

Question 20

why are some chromosome mutations lethal

Answer 20

due to the substantial changes they make to genetic information

Question 21

what is a homologous chromosome

Answer 21

same length and same genes in same place

Question 22

what is a non-homologous chromosome

Answer 22

different length and don’t have same genes in same place

Question 23

what is translocation

Answer 23

a section of on chromosome breaks off and becomes attached to another chromosome (not its homologous partner)

Question 24

what is inversion

Answer 24

when a section of chromosomes is reversed

Question 25

what is duplication

Answer 25

when a section of chromosome is added from its homologous partner

Question 26

why are mutations important in evolution

Answer 26

they are the only new source of alleles for a gene which can provide a survival advantage during environmental change. this gives rise to evolution

Question 27

why is gene duplication important in evolution

Answer 27

allows one copy of the gene to undergo single gene mutation without affecting function of original gene. new allele could appear