gene mutation

Question 1

define mutation

Answer 1

a spontaneous change in the DNA of a gene through either base substitution or base deletion

Question 2

how does base substitution work

Answer 2

• a base in the template strand is misread by the mRNA
• the mRNA codes for the wrong complimentary base on the strand
• the wrong base sequence forms and the tRNA carries the wrong amino acid to the sequence (wrong codon= anticodon compliementry to the wrong one)
• the wrong polypeptide sequence is formed

Question 3

base deletion

Answer 3

• a base is not read/ ignored
  causes all of the bases top move up 1 space from where they’re suppose to be in order to code correctly (frameshift occurs)
• the bases are all now in the wrong place so all of the codons are incorrect
• all the amino acids could be completely different to what they’re meant to be (dependent on with placement of the base)
• now the whole polypeptide is wrong

Question 4

what is the exception for base deletion for polypeptide production

Answer 4

if the base is the third one that’s ignored the amino acid coded may not be wrong due to the degenerative nature of the DNA code- ie there’s more than 1 codon that codes for a particular amino acid

Question 5

how do mutations occur in someone

Answer 5

either inherited or developed

Question 6

how can mutations be inherited

Answer 6

the mutation could be in an organ that produced gametes and then the offspring have the mutation based onto them

Question 7

what happens if a mutation is developed in a specific organ

Answer 7

if the mutation occurs in a specific organ cell etc this could damage or alter how the organ works or what the organ produces ie liver and insulin
if the mutation is developed in a cell under constant division this could increase the rate of division and alternate the stop stages f the cell cycle provide uncontrollable division causing malignant or benign tumours which could cause death (somatic division)