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Question 18M.3.hl.TZ2.11

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Date May 2018 Marks available [Maximum mark: 3] Reference code 18M.3.hl.TZ2.11
Level hl Paper 3 Time zone TZ2
Command term Outline, Sketch Question number 11 Adapted from N/A
11.
[Maximum mark: 3]
18M.3.hl.TZ2.11

Hemoglobin contains an iron ion that can bind to oxygen as part of the process of respiration.

(a)

Hemoglobin’s oxygen dissociation curve is shown at a given temperature. Sketch the curve on the graph at a higher temperature.

M18/4/CHEMI/HP3/ENG/TZ2/11.a

[1]

Markscheme

curve below original curve «showing lower affinity for oxygen» beginning at 0

 

Award mark if end of student curve does not finish at same location as original curve.

[1 mark]

(b)

Outline two differences between normal hemoglobin and foetal hemoglobin.

[2]

Markscheme

Any two of:

foetal hemoglobin has higher affinity for oxygen «than normal hemoglobin»

foetal hemoglobin is less sensitive to inhibitors/2,3-bisphosphoglycerate/2,3-BPG/DPG «than normal hemoglobin»

foetal hemoglobin contains two gamma units instead of the two beta units found in adult hemoglobin

[2 marks]