Topic 8A - Mutations and Gene Expressions

Question 1

Why might addition mutations cause major changes to a protein, and why might it not?
(3)

Answer 1

Addition mutations result in frame shifts if there are one or two bases added. All triplet codes to the right will alter, therefore changing the amino acid sequence / primary structure of the protein. If there are three additions close together, only a small section is layered / potentially only the addition of one amino acid.

Question 2

Describe what is meant by induced pluripotent stem cells.

Answer 2

• and they unspecialise

Induced pluripotent stem cells are pluripotent stem cells formed from unipotent stem cells / somatic / body cells. (1)
They are formed by using transcription factors to stimulate. (1)

Question 3

note

Answer 3

tightly condensed histones may make a gene hard to access due to lack of acetylation, and so is inactive / switched off.