June 2013

Question 1

Describe the role played by myosin in muscle contraction

Answer 1

Myosin head binds to actin, forming cross bridges

Myosin detached from actin and moves further along

Question 2

How do you work out a percentage increase

Answer 2

Big - small

Divided by small

Question 3

Explain how a carrier molecule on its own can prevent the infection of cells of a disease.
(So carrier molecule without siRNA)

Answer 3

Carrier binds to disease’s antigen

Prevents the disease from binding to the cell

Question 4

Explain why the DNA probe that was used was from an exon on the DNA not an intron

Answer 4

Introns not in mRNA
Introns don’t code for amino acids
Mutations of exons affects amino acid sequence so it’s important to know if exons affected not introns

Question 5

Explain why there is an increase in oxygen consumption when temperature increases

Answer 5

Increase temperature causes faster enzyme activity

So fast rate of respiration hence more oxygen consumed