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ZZZ AS level: Biology > Mutations > Flashcards

Flashcards in Mutations Deck (14)
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1
Q

what are mutations?

A

a sudden change in the amount or arrangement of genetic material in a cell

2
Q

what is a gene mutation?

A
  • change in sequence of bases in DNA
3
Q

state two types of gene mutations

A
  • base substitution

- base deletion

4
Q

what is base substitution?

A

nucleotide is replaced by another

5
Q

how does base substitution affect the amino acid sequence and what consequences can arise?

A
  • some mutations do not affect the sequence due to degenerate nature of genetic code
  • however, if the mutation affects the sequence, then mRNA copy is altered - different complementary anticodon of tRNA - so different primary structure so altered tertiary structure will affect the active site. This could produce a non-functional protein
6
Q

what is base deletion?

A

nucleotide is lost from DNA sequence`

7
Q

what is the effect of deletion?

A
  • causes frameshift
  • different amino acid sequence
  • polypeptide unlikely to function
8
Q

what can affect the rate of gene mutation?

A

mutagenic agents increase the rate

9
Q

what is a chromosome mutation

A

change in the structure or number of whole chromosomes

10
Q

what is the term to explain when there is three or more sets of chromosomes?
- in which organisms does this usually occur?

A
  • polyploidy

- in plants

11
Q

what is the term to explain when a pair of chromosomes fail to separate in meiosis?

A

non-disjunction

12
Q

give an example of a condition due to non-disjunction

A

down’s syndrome - gamete has extra chromosome so offspring has extra chromosome (21)

13
Q

will the mutation be inherited in somatic mutation?

A

no

14
Q

will the mutation be inherited in gametic mutation

A

yes

- occurs in gomads