AQA AS BIOLOGY PAPER 1 VIEW AHEAD
EXAM WITH TESTED QUESTIONS AND
ANSWERS 2026
‣ large molecules often contain carbon. why? Answer: they can readily
form bonds with other carbon atoms. this forms a 'backbone'. other
atoms can then attach.
‣ describe benedicts test for reducing sugars Answer: add equal volumes
of the sugar sample and benedicts reagent.
heat the mixture in a water bath for 5 minutes.
brick red precipitate will form.
‣ what is a reducing sugar? Answer: a sugar that can reduce (give
electrons to) another chemical.
‣ describe the benedicts test for non reducing sugars Answer: with food
sample, add an equal volume of dilute hydrochloric acid in a test tube.
place test tube in water bath for 5 mins.
add sodium hydrogencarbonate solution.
heat resulting solution with an equal volume of benedicts. solution for 5
minutes.
turns orange/brown.
,‣ what does dilute hydrochloric acid do in the benedicts test for non
reducing sugars? Answer: it hydrolyses any disaccharide into
monosaccharides, thus also forming reducing sugars.
‣ describe the structure of starch Answer: chains of alpha glucose
some chains are branched= amylopetcin
some chains are coiled= amylose
‣ what purpose does the structure of amylose serve? Answer: makes the
molecule compact so it is stored more easily.
‣ what purpose does the structure of amylopectin serve? Answer: more
surface area for enzymes to work on, thus glucose molecules can be
released at a much quicker rate.
‣ how is the structure of starch suited to its function? Answer: 1. starch
is insolube so it doesnt affect water potential
2. it is large enough that it doesnt diffuse out of cells
3. compact enough so that a lot of it can be stored in a small space
4. branched= each end can simultaneously be acted on by enzymes, so
glucose is quickly released
‣ how is the structure of glycogen suited to its function? Answer: 1.
insoluble, so no effect on water potential of cell
2. insoluble, so doesnt diffuse out of cells
, 3. compact, a lot of it can be stored in a small space
4. very highly branched= each end can simultaneously be acted on by
enzymes, so glucose is quickly released
‣ why do animals need highly branched glycogen? Answer: because
animals metabolic rate is faster than plants and so needs glucose to be
released quicker.
‣ describe the structure of cellulose Answer: made up of straight chains
of beta glucose
the chains are parallel to each other, so H bonds form cross-linkages
all the H bonds together strengthens the cellulose
forms microfibrils
‣ draw alpha and beta glucose Answer:
‣ how does the structure of triglycerides relate to their properties?
Answer: 1. triglycerides have a high ratio of energy-storing carbon-
hydrogen bonds to carbon atoms, so its a good source of energy.
2. low mass to energy ratio, so theyre good energy storage molecules.
3. large and non-polar, therefore insoluble, therefore don't affect
osmosis.
4. high ratio of hydrogen to oxygen atoms, so can release water when
oxidised, hence provide a source of water
EXAM WITH TESTED QUESTIONS AND
ANSWERS 2026
‣ large molecules often contain carbon. why? Answer: they can readily
form bonds with other carbon atoms. this forms a 'backbone'. other
atoms can then attach.
‣ describe benedicts test for reducing sugars Answer: add equal volumes
of the sugar sample and benedicts reagent.
heat the mixture in a water bath for 5 minutes.
brick red precipitate will form.
‣ what is a reducing sugar? Answer: a sugar that can reduce (give
electrons to) another chemical.
‣ describe the benedicts test for non reducing sugars Answer: with food
sample, add an equal volume of dilute hydrochloric acid in a test tube.
place test tube in water bath for 5 mins.
add sodium hydrogencarbonate solution.
heat resulting solution with an equal volume of benedicts. solution for 5
minutes.
turns orange/brown.
,‣ what does dilute hydrochloric acid do in the benedicts test for non
reducing sugars? Answer: it hydrolyses any disaccharide into
monosaccharides, thus also forming reducing sugars.
‣ describe the structure of starch Answer: chains of alpha glucose
some chains are branched= amylopetcin
some chains are coiled= amylose
‣ what purpose does the structure of amylose serve? Answer: makes the
molecule compact so it is stored more easily.
‣ what purpose does the structure of amylopectin serve? Answer: more
surface area for enzymes to work on, thus glucose molecules can be
released at a much quicker rate.
‣ how is the structure of starch suited to its function? Answer: 1. starch
is insolube so it doesnt affect water potential
2. it is large enough that it doesnt diffuse out of cells
3. compact enough so that a lot of it can be stored in a small space
4. branched= each end can simultaneously be acted on by enzymes, so
glucose is quickly released
‣ how is the structure of glycogen suited to its function? Answer: 1.
insoluble, so no effect on water potential of cell
2. insoluble, so doesnt diffuse out of cells
, 3. compact, a lot of it can be stored in a small space
4. very highly branched= each end can simultaneously be acted on by
enzymes, so glucose is quickly released
‣ why do animals need highly branched glycogen? Answer: because
animals metabolic rate is faster than plants and so needs glucose to be
released quicker.
‣ describe the structure of cellulose Answer: made up of straight chains
of beta glucose
the chains are parallel to each other, so H bonds form cross-linkages
all the H bonds together strengthens the cellulose
forms microfibrils
‣ draw alpha and beta glucose Answer:
‣ how does the structure of triglycerides relate to their properties?
Answer: 1. triglycerides have a high ratio of energy-storing carbon-
hydrogen bonds to carbon atoms, so its a good source of energy.
2. low mass to energy ratio, so theyre good energy storage molecules.
3. large and non-polar, therefore insoluble, therefore don't affect
osmosis.
4. high ratio of hydrogen to oxygen atoms, so can release water when
oxidised, hence provide a source of water
