AQA A-level Biology paper 1
AQA A-level Biology paper 1 Exam
Questions Containing 134 Terms with
Certified Answers 2024-2025.
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.
1
, AQA A-level Biology paper 1
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 hydrogen carbonate 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= amylopectin
some chains are coiled= amylose
what purpose does the structure of amylose serve? - Answer: makes the molecule
compact so it is stored more easily.
2
, AQA A-level Biology paper 1
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
insoluble so it doesn’t affect water potential
2. it is large enough that it doesn’t 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 doesn’t 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
3
AQA A-level Biology paper 1 Exam
Questions Containing 134 Terms with
Certified Answers 2024-2025.
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.
1
, AQA A-level Biology paper 1
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 hydrogen carbonate 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= amylopectin
some chains are coiled= amylose
what purpose does the structure of amylose serve? - Answer: makes the molecule
compact so it is stored more easily.
2
, AQA A-level Biology paper 1
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
insoluble so it doesn’t affect water potential
2. it is large enough that it doesn’t 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 doesn’t 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
3
