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DNA

2017 Paper Two

Question Nine
Looking at past AQA A-level Chemistry questions, I wanted to go beyond the answers and focus on thought processes, ideas and tips that will help in examinations.

The series will help you to spot weaknesses and help with revision, or it can serve as addenda to your notes.If you haven't gone through the paper, please look up the questions at www.aqa.org.uk, or click the direct link below, and have a go...

AQA A-level CHEMISTRY Paper 2 Organic and Physical ChemistryMonday 19 June 2017

Data Booklet here



Straightforward recall question
X – base, Y – phosphate (group)

The mark scheme states 'any mention of sugar in either loses that mark'. The sugar has already been drawn for you (deoxyribose)


Adenine hydrogen bonds to thymine (A-T, G-C)


The drawn molecule must be thymine and you will need to arrange the molecule to show the hydrogen bonding
You will lose marks for any errors in the structure of thymine, its orientation or in the hydrogen bonding.


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