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Date November 2018 Marks available 2 Reference code 18N.3.sl.TZ0.5
Level SL Paper 3 Time zone TZ0
Command term Explain Question number 5 Adapted from N/A

Question

Dietary recommendations are made by scientists.

The formation of proteins from amino acids is an example of an anabolic reaction in the human body.

State the source of energy for such a synthetic reaction.

[1]
a.

Suggest why it is advisable for those living in northerly or southerly latitudes (that is away from the equator) to take vitamin D supplements during the winter.

[1]
b.

Explain how a xenobiotic is biomagnified.

[2]
c.

Markscheme

catabolism «of food/nutrients»

OR

«cellular» respiration ✔

 

Accept “ATP” but not “burning of food/nutrients”.

a.

not enough sunlight/UV light «for synthesis of vitamin D in the skin» ✔

b.

cannot be metabolized/broken down

OR

not biodegradable

OR

accumulates in lipid/fat tissues ✔

 

increased concentration as one species feeds on another «in the food chain» ✔

c.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.

Syllabus sections

Options » B: Biochemistry » B.6 Biochemistry and the environment
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Options » B: Biochemistry
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