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Question 20N.3.HL.TZ0.13a

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Date November 2020 Marks available [Maximum mark: 3] Reference code 20N.3.HL.TZ0.13a
Level HL Paper 3 Time zone TZ0
Command term Describe Question number a Adapted from N/A
a.
[Maximum mark: 3]
20N.3.HL.TZ0.13a

Plant-derived proteins are likely to be safer for human use than those derived from mammalian cell cultures, as plant pathogens are not harmful to humans. The hepatitis B vaccine has been produced in tobacco plants.

(a)

Describe how the tobacco mosaic virus is used in the production of hepatitis B vaccine.

[3]

Markscheme

a. fusion between genes of (viral) capsid and hepatitis B antigen/HBsAg;

b. (transformed) virus infects tobacco plant;

c. tobacco plant expresses antigen/HBsAg;

d. HBsAg producing plants fed to animals;

e. animals produce anti-HBsAg antibodies;

Examiners report

Most have some knowledge of the usage of the tobacco mosaic virus but had difficulty in providing clear answers.

Syllabus sections