RNA Interference Case Study Activity
Teacher Resource 1
Question
(a)
Expected Answer
(i)
Marks
mRNA enters cytoplasm / DNA stays in nucleus 
mRNA, translated / used to make, protein 
mRNA short-lived  ora (or reverse argument)
DNA, transcribed / used to make, mRNA 
(ii)
max 2
siRNA smaller / fewer nucleotides / only matches part of gene  ora
siRNA double-stranded  ora
2
complementary base-pairing 
(b)
hydrogen bonding 
between purines and pyrimidines 
A with U  DO NOT ACCEPT A with T
C with G 
ref. 2 or 3 bonds (correct context) 
(c)
(i)
Max 3
(CCR5)
siRNAs continue to work in long-lived cells 
siRNAs diluted as lymphocytes divide 
(ii)
2
(CCR5)
because no essential function in body / absence not a problem 
1
[Total: 10]
Version 1
Gene technologies
1
© OCR 2016
This case study activity is adapted from OCR 2806/01 June 2007 Q.5.
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Version 1
Gene technologies
2
© OCR 2016