mutations 1.4

Question 1

mutation

Answer 1

a random change to an organisms genetic information (DNA)

Question 2

what happens to proteins in a mutation

Answer 2

can result in no protein or an altered protein being synthesised or can have no effect on the phenotype

Question 3

what increases the rate of mutations

Answer 3

mutagenic agents

Question 4

examples of mutagenic agents

Answer 4

chemicals (mustard gas) and radiation (UV light)

Question 5

genetic disorders

Answer 5

is a condition or disease related to an individuals genotype

Question 6

what causes genetic disorders

Answer 6

caused by mutations which result in a protein not being expressed or a faulty protein being expressed

Question 7

single gene mutation

Answer 7

involve the DNA nucleotide sequence being altered by one gene in a chromosome

Question 8

point mutation

Answer 8

when only one nucleotide is changed

Question 9

types of single gene mutations

Answer 9

substitution, insertion and deletion

Question 10

substitution

Answer 10

occurs when one nucleotide is substituted (replaced) by another

Question 11

what can substitution mutations cause

Answer 11

a missense or nonsense mutation or a splice site mutation

Question 12

missense mutation

Answer 12

one amino acid is changed for another which may result in a non functional protein or it may have a little effect on the protein

Question 13

nonsense mutation

Answer 13

altered mRNA codon is replaced by a stop codon so translation stops prematurely, the protein is shorted and doesn’t function

Question 14

splice site mutation

Answer 14

-the removal of introns from the primary mRNA transcript during RNA splicing is controlled by splice sites that appear at the end of an intron before an exon

-when a mutation at one of these site causes an intron to be retained in error and/or an exon to be removed in error, the altered mRNA transcript may be translated into a protein that doesn’t function properly

Question 15

what causes frameshift mutations

Answer 15

insertion or deletion mutations

Question 16

what happens when a frameshift mutation occurs

Answer 16

all the codons and amino acids after the mutation are altered which has a major effect on the structure of the protein produced during translation

Question 17

chromosome structure mutations

Answer 17

involves the change in the structure of one or more chromosomes and of the structure of a chromosomes changed it would bring about a change in the number or sequence of genes in that chromosome

Question 18

types of chromosome structure mutations

Answer 18

inversion, deletion, duplication and translocation

Question 19

inversion

Answer 19

occurs when a section of a chromosome is reversed (the genes switch places)

Question 20

deletion (chromosome structure mutations)

Answer 20

occurs when a section of a chromosome is removed (genes are missing)

Question 21

duplication

Answer 21

occurs when a section of one chromosome breaks off and joins onto its homologous partner (genes are duplicated in this chromosome)

Question 22

translocation

Answer 22

occurs when a section of one chromosomes breaks off and joins onto another chromosome that is not its homologous partner

Question 23

the two ways translocation can occur

Answer 23

non reciprocal translocation and reciprocal translocation

Question 24

non reciprocal translocation

Answer 24

a section of deleted genes from chromosome 2 join onto chromosome 1

Question 25

reciprocal translocation

Answer 25

a section of deleted genes from chromosome 2 join onto chromosome 1 and deleted genes from chromosome 1 join onto chromosome 2 (it’s been reciprocated)

Question 26

lethal effect

Answer 26

chromosome structure mutations often involve substantial change to their structure and have a lethal effect on the individual affected