A-level paper 1 mistakes

Question 1

Why might a patient have an unusually high proportion of eosinophils?

Answer 1

The patient will produce more of these cells due to an allergy

Question 2

Explain why heart cells are damaged as a result of heart disease.

Answer 2

Plaque can lead to arteries becoming blocked
This deprives heart cells of oxygen
So cells cannot respire

Question 3

Compare and contrast the properties and uses of embryonic stem cells and pluripotent stem cells (IPS cells)

Answer 3

Similarities:
Both are able to divide indefinitely
Both are able to differentiate into a number of different cells
Differences:
IPS cells were adult cells, embryonic cells taken from inner cell mass
IPS have a gene, embryonic stem cells don’t.
Less ethical issues surrounding IPS cells
IPS cells form adult cells whereas embryonic stem cells form younger cells

Question 4

Explain how a mutation can result in a shortened protein being produced.

Answer 4

The mutation may produce a stop codon
Therefore translation will stop sooner

Question 5

Some people have mutations that affect proteins involved in the electron transport chain.
Explain why these mutations lead to a build up of lactate.

Answer 5

Electron carriers can’t transport electrons
Reduced NAD will not be oxidised
So pyruvate will produce lactate