Mutations

Question 1

what is a gene mutation?

Answer 1

= change in a base of the sequence of DNA
= occur spontanoiusly
= result to a different amino acid sequence in the polypeptide

Question 2

What causes mutations?

Answer 2

= high energy radiation- x-rays gamma rays ext
= carcinogens-

Question 3

What happens in addition?

Answer 3

= extra base is added to the sequence
= frame shift
= alters the dna sequence, and codons so the encoded amino acid may be different resukting to a non-functional protein

Question 4

WHat is deletion?

Answer 4

= deletion of a base in a sequence
= frame shift to the left
= different polypeptide chain and a non-functioning protein

Question 5

What is substitiuon?

Answer 5

= one base has changed for another base
= number of bases remains same
= changes one base, but as genetic code is denegnerate amino acids may have more than 1 triplet
= so may have no impacy
=

Question 6

What is an inversion dna?

Answer 6

= section of bases detach and are rejoin inverted
= different amino acids for a different region

Question 7

What is translocation?

Answer 7

= section of bases on one chromosome detaches and attaches to another chromosome
= changes gene expression and genome
=

Question 8

What do mutagenic agents do?

Answer 8

= increases/rate or chance of gene mutation

Question 9

Why may mutations not have an affect or may have a positive effect?

Answer 9

= degenerate code
= no frame shift
= affect the introns only- non coding regions
= the protein changed, teritary structure, may not be non-functioning may have a positive effect
= may lead to a new allele, so allows more genetic variatio