B3 2018

Question 1

The acidic pH conditions created by osteoclasts cause the inactive form of the protein osteocalin to change into the active form of oseocalcin, How?

Answer 1

pH changes the teritary structure of the active site
Changes the hydrogen bonds

Question 2

Binding of insulin leadsto an increase in the rate of respiration in cells such as osteoblasts

Answer 2

More transport proteins
More glucose enters cell

Question 3

When counting cells thatt touch top or left lines are counted but cels that touch right or bottom lines are not counted, why?

Answer 3

To avoid counting same cells twice
To allow comparison

Question 4

When counting white blood cells, the doctor only diluted the bloood samplle by a factor of 20 times, instead of 200 times when counting red blood cells

Answer 4

Fewer white blood cells so no need to dilute

Question 5

The scientists began by lysing cells and organelles usini a detergent that dissolves lipids in water. Suggest how the detergent releases CENP-W from cells

Answer 5

Cell membrane made from phospholipid
Dissolves the phospholipid

Question 6

Explain how ultracentrifugation separates CENP-W from other molecules

Answer 6

Spin at very high speeds
Seprate depending on mass

Question 7

This method allowed the scientists to estimate the expression of the amoA gene in each culture but not the growth of the bacterial population in each culture Why?

Answer 7

Didnt count bacteria
Copies of mRNA related to enzyme produced
Dont kknow how much mRNA produced by each cell
Dnot know if aomA linked to cell division

Question 8

Suggest one suitable method for sterilising the bottles and explain why it was necessary to sterilise them

Answer 8

Boiling in hot water
Remove bacteria that might break down ammonia