DP Chemistry (last assessment 2024)

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Question 20N.3.sl.TZ0.6b(i)

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Date November 2020 Marks available [Maximum mark: 1] Reference code 20N.3.sl.TZ0.6b(i)
Level sl Paper 3 Time zone TZ0
Command term Identify Question number b(i) Adapted from N/A
b(i).
[Maximum mark: 1]
20N.3.sl.TZ0.6b(i)
Phospholipids are a main component of cell membranes.

 

(b(i))

A representation of a phospholipid bilayer cell membrane is shown:

© International Baccalaureate Organization 2020.

Identify the components of the phospholipid labelled A and B.

[1]

Markscheme

A: phosphate/ionic group
AND
B: alkyl/hydrocarbon «chain» ✔


Accept "glycerol «fragment»" OR "glycerophosphate" OR “ester” for A.

Accept “fatty acid «tail»” for B.

Do not accept terms such as “polar head”, “non-polar tail”, “hydrophilic” OR “hydrophobic” for components alone.

Examiners report

Mostly well answered. Weaker candidates used the terms hydrophobic (non-polar) tail and/or hydrophilic (polar) head and therefore lost the mark. Students are expected to know the names of these structures.

Syllabus sections