2017

Question 1

Use information in this question to calculate how many bacteria were present in
1 cm3 of undiluted liquid culture.

Answer 1

6 000 000

Question 2

The student concluded that the minimum concentration of propan-2-ol needed to
stop the growth of Lactobacillus was 15 units. This conclusion is incorrect.
Describe how you could obtain a more accurate estimate of the minimum
concentration of propan-2-ol needed to stop the growth of this species of
bacterium.

Answer 2

Find several values between 10 and 15 units then make repetitions of each.

Question 3

Explain the advantages of lipid droplet and micelle formation

Answer 3

Droplets increase surface area for lipase enzyme actions so there would be faster hydrolysis. Micells carry fatty acids, glycerol, and monoglycerides through the membrane to the intestinal epithelial cell.

Question 4

Lymphoedema is a swelling in the legs which may be caused by a blockage in
the lymphatic system.
Suggest how a blockage in the lymphatic system could cause lymphoedema.

Answer 4

Excess of tissue fluids builds up.

Question 5

Explain the result for the chip in 0.8 mol dm–3 sucrose solution

Answer 5

0.8 mol dm sucrose solution has a lower water potential therefore water moves into the sucrose solution by osmosis.

Question 6

2017 last question