Guide to using these solutions;
Every answer written in red represent what an A1 candidate would present to the examiner.
All of the information written in black font would not be required in the exam; its purpose is
to provide detailed explanations, to give context and related definitions so as to ultimately
deepen your understanding of the concepts being tested. To get the most out of your past
exam papers, I recommend that you approach all of them in this manner yourself too; don’t
simply answer the question and move on as you would in the real exam. Rather, use each
question as an opportunity to revise specific sections of the course. Don’t simply learn the
answers by heart, put them in context and focus on understanding their relationships with
other aspects of the course. You will find that each paper suddenly becomes the equivalent
of two or three as you start generating your own questions that parallel with those
presented. Best of luck!
Section A; answer any five questions.
1. Answer any 5 of the following parts (a) to (f):
(a) Monosaccharides. These are are the simplest units of carbohydrates.
Monosaccharides are essentially single sugar units (a ring of carbon atoms).
Glucose and fructose are examples of two important monosaccharides found in
living things.
(b) Digestion. Digestion is a catabolic process (i.e. the combination of physical and
mechanical breakdown processes in the body that breaks complex molecules
down into simpler ones) that, in the case of carbohydrates, breaks down
polysaccharides into monosaccharides so that the body can absorb them
(primarily in the ileum and jejunum of the small intestine).
(c) Y=6. The carbohydrate referred to here is glucose, a monosaccharide of the
formula C6H12O6. Digested from a polymeric form (starch for example), this is the
only energy source that can be utilised by all cells in the human body.
(d) Cellulose. Be careful not to mix up cellulose and starch. Cellulose has more cross
bonding between the chains, and cannot be digested by humans as we lack the
enzyme needed to break the bonds linking the glucose molecules together. This
is why it is used as fibre in the diet-to stimulate peristalsis.
(e) Starch. Plants store glucose in the form of this polysaccharide, while humans
store glucose as glycogen in liver and muscle tissue.
(f) Deoxyribose. Be careful here…why would ribose not be an acceptable answer?
Think about one key distinction between RNA and DNA…
2. (a) All of the competing individuals get some of the resource. This contrasts with
contest competition, in which one individual gets all of the resource and the other is
left without it.
(b) Water. Minerals or space are all acceptable answers here too.
(c) Mates. Water, shelter and territory are all acceptable here too.