4.8 Metabolism
6 exam questions worth 10 marks. Write your answer, open the mark scheme, then give yourself the marks you earned. Your answers are saved on this device.
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Define metabolism.
Mark scheme
the sum of all the reactions in a cell / the body
Model answer
Metabolism is the sum of all the reactions in a cell or the body.
Name the storage carbohydrate made from glucose in (a) plants and (b) animals.
Mark scheme
- (a) starch (1)
- (b) glycogen (1)
Model answer
Plants store starch, and animals store glycogen.
What is a lipid molecule made from?
Mark scheme
- one glycerol (molecule) (1)
- three fatty acids (1)
Model answer
One molecule of glycerol joined to three fatty acids.
Describe what happens to excess amino acids in the body.
Mark scheme
- broken down / converted to urea in the liver (1)
- urea removed by the kidneys / in urine (1)
Model answer
Excess amino acids are converted into urea in the liver, and the urea is removed by the kidneys in urine.
Explain why metabolic reactions depend on respiration.
Mark scheme
- respiration transfers / releases energy (1)
- which is needed to build larger molecules / for the reactions (1)
Model answer
Respiration releases the energy that cells need to build larger molecules, such as proteins and glycogen.
Which molecule is used to strengthen plant cell walls?
Choose one answer.
Correct Not quite: the answer is Cellulose
Mark scheme
A: cellulose
Model answer
A: cellulose, made from glucose.
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