Mutations

Question 1

Mutation

Answer 1

• sudden, permanent and heritable change to the DNA sequence

- such changes will be transcripted to mRNA and get translated into proteins leading to disease expression

Question 2

Point mutation

Answer 2

• refers to a single base alteration in DNA
• point mutations are usually substitutions where one base is replaced by another
• it is a transisiton if a purine is relaced for a purine etc or a transversion if a purine is replaced by a pyramidine and vice versa

Question 3

Frame shift

Answer 3

• the deletion or insertion is not in multiples of three codons
• this leads to a shift in the triplet reading frame with variable results

Question 4

Silent mutations

Answer 4

no change in protein product occurs as the single amino acid is often coded for by more than one triplet sequence

Question 5

Misense mutation

Answer 5

-the new mutant codon specifies a different amino acid with variable effects on the final protein product

Question 6

Non-sense

Answer 6

-the new codon is UUA, UGA or UAG and codes for STOP so the amino acid is actually a non-functional protein

Question 7

Translocation

Answer 7

• refers to exchange of chunks of genetic materials from one chromosome to another
• these are essentially mutations occurring at larger dimensions
• mostly reciprocal so one segment is exchanged for another among chromosomes

Question 8

Robertsonian translocation

Answer 8

• non reciprocal that results in a single dused chromosome from 2 acrocedntric chromosomes
• the small p arms are discarded and metacentric fusion occurs
• thus from 2 chromosomes a single chromosome is formed with no significant loss of genetic material
• hence these are viable and balanced within the individual in whom they occur
• however in gametes this reults in unbalanced translocation