MetabolismIB MYP Biology: Topic test

1. 1
   A baby elephant in a sanctuary in Thailand doubles its mass in a few months. Its body is building new muscle from amino acids, while its cells also break down glucose to release energy.

   (a)

   Which term describes all of the chemical reactions that take place in the elephant's body?

   [1 mark]

   • ADigestion
   • BMetabolism
   • CRespiration
   • DExcretion

   (b)

   Which of these is an anabolic reaction?

   [1 mark]

   • ARespiration of glucose in muscle cells
   • BDigestion of protein in the stomach
   • CBuilding muscle protein from amino acids
   • DBreaking down glycogen to glucose

   (c)

   Distinguish between anabolic and catabolic reactions, using an example from the elephant for each.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A teacher in Accra traces a mouthful of bread through the gut with her class. The bread is chewed, swallowed, churned in the stomach and then passes into the small intestine, where the digested food is absorbed into the blood.

   (a)

   In which part of the gut is most digested food absorbed into the blood?

   [1 mark]

   • AMouth
   • BStomach
   • CLarge intestine
   • DSmall intestine

   (b)

   What does peristalsis do?

   [1 mark]

   • AMuscles squeeze to push food along the gut
   • BEnzymes break starch down into sugars
   • CBile breaks fat into small droplets
   • DAcid kills bacteria in the food

   (c)

   Distinguish between mechanical digestion and chemical digestion. Give one example of each.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A student investigates catalase, an enzyme found in liver that breaks down hydrogen peroxide into water and oxygen. She adds 1 g of liver to hydrogen peroxide at different temperatures and measures the volume of oxygen collected in 60 seconds. The volumes were 4 cm³ at 10 °C, 9 cm³ at 20 °C, 15 cm³ at 30 °C, 17 cm³ at 40 °C, 6 cm³ at 50 °C and 0 cm³ at 60 °C.

   (a)

   Describe how the volume of oxygen changes as the temperature increases.

   [3 marks]

   (b)

   Explain these results.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A mountaineer in Nepal climbs from sea level to 4000 m. The air at this height contains less oxygen. After a few weeks, his breathing rate and heart rate are higher than at sea level, and his body makes more red blood cells. Some athletes inject themselves with extra red blood cells before a race, which is banned by sports organisations.

   (a)

   Explain how his breathing system and circulatory system work together to supply oxygen to his muscles at altitude.

   [6 marks]

   (b)

   Discuss whether athletes should be allowed to inject extra red blood cells to improve their performance.

   [6 marks]

   Total for question 4: 12 marks

5. 5
   A nutritionist in Manila plans a lunch for a young athlete. It contains grilled fish, brown rice and a mango.

   (a)

   Which nutrient in the fish is needed for the growth and repair of muscle?

   [1 mark]

   • AProtein
   • BCarbohydrate
   • CVitamin D
   • DFibre

   (b)

   How could the nutritionist test the mango for reducing sugar?

   [1 mark]

   • AAdd iodine solution and look for a blue-black colour
   • BHeat with Benedict's solution and look for a brick-red colour
   • CAdd biuret solution and look for a purple colour
   • DAdd ethanol, then water, and look for a cloudy emulsion

   (c)

   Explain why the athlete's diet should contain calcium and iron.

   [2 marks]

   Total for question 5: 4 marks

6. 6
   A cook in Seoul sprinkles salt on slices of cucumber. After twenty minutes the slices have become soft and limp and are sitting in a pool of liquid.

   (a)

   Which process moved the water out of the cucumber cells?

   [1 mark]

   • AActive transport
   • BDigestion
   • COsmosis
   • DTranspiration

   (b)

   Before the salt was added, the cucumber cells were firm. Which word describes a plant cell that is full of water and pushing against its cell wall?

   [1 mark]

   • AFlaccid
   • BPlasmolysed
   • CDenatured
   • DTurgid

   (c)

   Explain why the water moved out of the cucumber cells.

   [2 marks]

   Total for question 6: 4 marks

7. 7
   A student wants to find out whether leaves lose more water vapour through their upper surface or their lower surface. She takes three leafy stems of the same plant. She smears petroleum jelly, which blocks stomata, on the upper surface of every leaf on stem 1, on the lower surface of every leaf on stem 2, and on neither surface on stem 3. She stands each stem in water and measures the mass of each stem every day for three days.

   (a)

   Predict which stem will lose the least mass, and explain your prediction.

   [3 marks]

   (b)

   Identify the independent variable and the dependent variable, and describe two variables that she must control.

   [4 marks]

   Total for question 7: 7 marks

8. 8
   A woman in Chennai has kidney failure. Her kidneys can no longer filter her blood, so waste products and excess water build up in her body. She has dialysis three times a week, four hours each time, and is on the waiting list for a kidney transplant. A relative has offered to donate one of their two kidneys.

   (a)

   Explain why kidney failure is life-threatening and how dialysis helps.

   [6 marks]

   (b)

   Discuss whether the woman should have a kidney transplant from her relative rather than carrying on with dialysis.

   [6 marks]

   Total for question 8: 12 marks

End of questions