MUTATIONS

Question 1

what are mutations?

Answer 1

mutations are permanent changes in the base sequences of DNA

Question 2

what are the main causes of mutations?

Answer 2

main causes are an accidental change when the cell is replication its DNA and by mutagens such as radiation, chemicals, or viruses.

Question 3

how does a mutation in DNA alters the protein produced?

Answer 3

when a mutation occurs, the sequence of triplets in DNA changes, meaning a different mRNA codon sequence during transcription - meaning dif tRNAs at the ribosome during translation which produces a dif amino acid sequence in the protein so the protein may fold incorrectly or not function.

Question 4

what is substitution? and its effect?

Answer 4

where it results in a whole new amino acid being added to the polypeptide chain the effects can vary between silent, missense, and nonsense mutation.

Question 5

what is insertion and deletion? and its effect?

Answer 5

insertion and deletion mutations cause a frameshift in the whole sequence of amino acids because each base is shuffled into a new codon

Question 6

what is a frame-shift - why does it have a bad effect?

Question 7

define what silent, missense, and nonsense mutation mean in terms of the effects of substituion.

Answer 7

Silent mutation: No change in the protein’s function
Missense mutation: A change in one amino acid, which may alter the protein’s function
Nonsense mutation: A premature stop codon, resulting in a shortened protein that is often nonfunctional