Past Paper Q

Question 1

Why do cells not store glucose/small molecules

Answer 1

Because they are permeable and would diffuse out of the cell by osmosis

Question 2

What is it called when a cell membrane Pulls way from a cell wall

Answer 2

Plasmolysed/flaccid

Question 3

Production of yoghurt

Answer 3

• boil milk (pasteurise) to kill microorganisms (sterilise) and to eliminate competition for lactose
• cool
• add lactobacillus bacteria (Only small quantities needed since they reproduce at a high rate)
• leave for 5 hours
• keep mixture warm at optimum temperature
• The bacteria breaks down lactose in milk to lactic acid by anaerobic respiration
• this binds the proteins suit they change shape due to lower pH and this thickens the milk
• lower pH prevents other microorganisms from reproducing

Question 4

Small intestine for efficiant absorption

Answer 4

• villus protrude to increase SA and allow more absorption of food at one time
• thin walls for short diffusion distance
• capillaries - glucose + amino acids
• lacteal - fatty acids + glycerol
• capillaries maintain concentration gradient
• villus is long so more diffusion and absorption

Question 5

Production of beer

Answer 5

• harvest and germinate barley grain which turns into malt
• add malt to warm water, leave it for a while, then boil and filter
• add hops and yeast
• leave to ferment
• filter and pasteurise
• bottle and cask