Gene expression

Question 1

name the 3 possible effects of a

Substitution mutation

Answer 1

no change to protein as DNA is degenerate

change to the primary sequence to protein as a different aa is coded for. (sickle cell anaemia)

stop codon is coded for instead significantly altering the protein. non- functional

Question 2

what are some examples of mutagenic agents?

Answer 2

high energy ionising radiation including U.V X-ray and alpha/beta

chemicals - from tobacco

Question 3

when does a mutation occur

Answer 3

mutations are very rare and occur spontaneously

can create PERMENANT changes in DNA during dna replication

Question 4

name possible effects of a deletion/addition muation

Answer 4

can result in frame shift as the dna code is read in triplets and non-overlapping.

can have a significant impact on the protein - larger effect

if multiple of 3 bases change then it has less of an impact as DIRECTLY affecting one aa rather than lots ‘downstream’ . This would be a Point mutation

Question 5

what is a gene mutation

Answer 5

any change to the sequence of dna bases

>change to the structure or quantity of DNA

Question 6

how to inhibit DNA trancription (3)

> epigenetics

Answer 6

increased methylation of dna
decreased acetylation of histones
do not involve oestrogen

Question 7

how is epigenetics different to mtations

Answer 7

can be altered by envrionmental factors and doesn’t affect the DNA base sequence but rather the structure of it