S2 Science: Digestion And Nutrients (Paper 2 (intermediate))

S2 Science: Digestion and Nutrients (Paper 2 (intermediate))

2026-11-14

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Tutor Prep Guide · The role of each part of the digestive tract, enzyme action and temperature, bile emulsifying fats, absorption by villi, and food tests for starch, reducing sugars, protein and fat

S2 Science: Digestion and Nutrients (Paper 2 (intermediate))

This paper covers enzyme specificity and temperature, the division of work between bile and pancreatic juice, villus structure, plus simple energy and fat calculations.

Direct answers　Enzymes are specific, work best at 37 degrees and denature above 60, bile is made by the liver and stored in the gall bladder, pancreatic juice is alkaline with three enzymes, and villi are thin walled with a large area and rich blood supply.

01　Paper details (check answers afterwards)

Item	Detail
Questions	10
Suggested time	20
Difficulty mix	Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1
Chapter	Chapter: S2 Science: Digestion and Nutrients
Level	S2

02　Questions (10 items)

FoundationWhat does the specificity of an enzyme mean?
FoundationAt what temperature do most human enzymes work best, and what happens at high temperature?
FoundationWhich organ makes bile and where is it stored?
IntermediateWhich three kinds of enzyme does pancreatic juice contain, and why is its acidity important?
IntermediateInto which two products does lipase split fat?
IntermediateState two structural features of a villus that help absorption.
ChallengeA person takes 2000 kcal a day, with 30 percent from fat. How many grams of fat is that? (fat gives 9 kcal per gram)
ChallengeHuman enzymes cannot digest fibre. What good does it do the digestive system?
ChallengeA long term lack of vitamin C causes which disease?
Error redoWhich statement is right? A: an enzyme is used up in the reaction; B: an enzyme can be used again after the reaction.

03　Answers and one-line notes

#	Answer	One-line note
1	One enzyme catalyses the reaction of only one substrate	The active site fits one particular substrate, which is why amylase cannot digest protein.
2	About 37 degrees Celsius, and above about 60 degrees the enzyme denatures and the loss is permanent	Heat destroys the three dimensional shape, so the active site no longer fits the substrate.
3	It is made by the liver and stored in the gall bladder	After a fatty meal the gall bladder contracts and sends bile into the small intestine.
4	Amylase, protease and lipase, and it is alkaline so it neutralises the stomach acid	Enzymes in the small intestine need nearly neutral conditions, so the alkaline juice neutralises the acidic chyme.
5	Glycerol and fatty acids	The smaller products can cross the intestine wall and enter the blood vessels inside the villi.
6	Microvilli increase the surface area, and the wall is only one cell thick with a rich blood supply	Large surface area, a short diffusion distance and fast removal are the three shared design features of absorbing structures.
7	600 kcal, about 66.7 g	2000 times 0.3 gives 600 kcal, and dividing by 9 gives 66.7 g.
8	It adds bulk, stimulates gut movement and helps waste pass, reducing constipation	Fibre soaks up water, so the stool becomes softer and passes through the colon more easily.
9	Scurvy	Vitamin C is needed to make collagen, so a lack leads to bleeding gums and slow healing wounds.
10	B is right	An enzyme is a catalyst, so its structure and amount are unchanged and it can work repeatedly.

04　What to do after marking

After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
Repeat the same item two days later; move to the next paper only when both attempts are correct.
Parents only need the answer and note columns; there is no need to explain every item.

For digestion questions ask three things: whether the question is about structure, an enzyme or a nutrient, which part of the tract the reaction happens in, and whether the colour change of a food test is being used.Tutor Registration →

Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.