Past paper wrong questions

Question 1

Describe how the small intestine is adapted for efficient absorption ( 5 marks)

Answer 1

Lots of villi that increases surface area
Walls of villi are once cell thick for shorter diffusion distance
S.I very long increasing time for absorption
Good blood supply to maintain concentration gradient
Cells have many mitochondria for aerobic respiration for active transport

Question 2

Define the term double circulatory system ( 1 mark)

Answer 2

Blood is pumped to the lungs by the right side of the heart
Blood is pumped to the body by the left side of the heart

Question 3

Explain why having only one ventricle makes the circulatory system less efficient than having two ventricles. ( 2 marks)

Answer 3

Oxygenated and deoxygenated blood mixes
Less oxygen reaches the body

Question 4

Explain why an axolotl may die in water with a low concentration of oxygen. ( 4 marks)
(Axolotl have gills fr)

Answer 4

Concentration gradient is less steep
Less oxygen diffuses into blood
Less aerobic respiration occurs - less energy released
Less metabolism

Question 5

Name one condition that could be treated using regenerated human tissue

Answer 5

Diabetes

Question 6

Explain how pancreatic cancer may cause a person to lose weight ( 4 marks)

Answer 6

Reduced enzyme production
Food not fully broken down
Less glucose absorbed into bloodstream
Less glucose available for respiration so fat used up in respiration

Question 7

Describe how the balance between the mass of food eaten and the amount of exercise a person does controls body mass ( 3 marks)

Answer 7

increased energy intake if more food eaten
if exercise more, more energy is transferred / released
if energy intake = energy released - mass stays the same

Question 8

Describe four differences between a bacterial cell and a plant cell ( 4 marks)

Answer 8

Bacterial cell does not have mitochondria - plant cell does
bacterial cell is smaller than a plant cell
bacterial cell does not have a PERMANENT vacuole plant cell does
bacterial cell has smaller ribosomes than plant cells

Question 9

Explain how vaccinating chickens reduces the number of cases of salmonella food poisoning. (2 marks)

Answer 9

Fewer bacteria in chicken
Fewer bacteria digested by humans

Question 10

Suggest why salmonella cases are higher in summer than winter ( 1 mark)

Answer 10

Warmer weather so bacteria reproduce quickly

Question 11

Explain how CHD can cause a heart attack ( 3 marks)

Answer 11

educed / restricted / stopped blood flow
(so) less oxygen reaches heart muscle
(so heart muscle cannot respire enough

Question 12

Explain how lifestyle and medical risk factors increase the chance of developing CHD ( 6 marks)

Answer 12

smoking – high bp / cholesterol / fatty deposition
* obesity – lack of exercise / high bp / cholesterol / fatty
deposition / diabetes
* exercise – obesity / bp /diabetes
*high fat diet – obesity / cholesterol / diabetes

Question 13

This is the method used.
1. Place the pondweed at 5 cm from the light source.
2. Measure the rate of photosynthesis by counting the number of bubbles produced
in 1 minute.
3. Repeat with the pondweed at 10 cm and at 20 cm from the light source
Two ways method could be improved ( 2 marks

Answer 13

measure the volume of gas
released
increase length of time