EXAM PAST PAPER QUESTIONS ANSWERS A LEVEL BIOLOGY - LIPIDS document

AQA
A-Level
BIOLOGY
3.1 | Biological Molecules
1.3 | Lipids

Time allowed
62 minutes

MARK SCHEME




Score Percentage

/52 %
4.1 | CELL BIOLOGY | QUESTION PAPER 1 1

, (a)




One mark for each correct column
Mark ticks only and ignore crosses
4




(b) 1. Two marks for box round two hydrogens and one of the oxygens from
OH groups on carbons 1 and 4;;

2. One mark from incorrect answer involving any two hydrogens and an
oxygen from carbons 1 and 4;
Do not award marks if all atoms concerned are on same
carbon atom or are on carbon atoms other than 1 and 4 or
where the answer does not have two hydrogen and one
oxygen
2




(c) (i) 1. Holds chains / cellulose molecules together / forms cross links
between chains / cellulose molecules / forms microfibrils, providing
strength / rigidity (to cellulose / cell wall);

2. Hydrogen bonds strong in large numbers;x
Principles here are first mark for where hydrogen bonds are
formed and second for a consequence of this.
Accept microfibres
2




(ii) Compact / occupies small space / tightly packed;
Answer indicates depth required. Answers such as “good for
storage”, “easily stored” or “small” are insufficient.
1
[9]