mutations

Question 1

what is a mutation

Answer 1

a random change in the DNA base sequnce that alters the amino acid being coded for therefore differs the polypeptide chain being produced

Question 2

when are mutations most likely to happen

Answer 2

during synthesis of interphase as it is where DNA replictaion occurs

Question 3

explain how a mutation can cause a non functional enzyme

Answer 3

• a change in the DNA base sequence will change the amino acid being coded for
• therefore the polypeptide chain alters and so the primary structure of the protein is disrupted
• ionic bonds, hydrogen bonds and disulphide bridges are disrupted affecting the secondary and tertiary structure of the protein
• this can change the shape of the active site and so no more enzyme-substrate complexes can form

Question 4

define mutagenic agents

Answer 4

factors which increase the rate of mutations

Question 5

give examples of mutagenic agents

Answer 5

carcogenic chemicals, ionising radiation

Question 6

give the 4 key exam points when describing a mutation

Answer 6

1. what mutation has occured the dna base sequenece
2. how has this changed the amino acid sequence
3. does it change the tertiary structure and therefore the active site
4. how does this lead to a non functional protein

Question 7

how do mutations lead to cancer

Answer 7

change in the Dna base sequence changing the amino acid sequence being coded for
leads to the uncontrollable cell division