S2 Science: Digestion And Nutrients (Paper 1 (basics))

S2 Science: Digestion and Nutrients (Paper 1 (basics))

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 1 (basics))

This paper covers the order of the digestive tract, enzymes in the mouth and stomach, absorption by villi, and the four basic food tests.

Direct answers　Digestion breaks large molecules into small ones, amylase starts in the mouth, bile emulsifies but is not an enzyme, and iodine, Benedict and biuret test starch, reducing sugar and protein.

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 is the main job of the digestive system?
FoundationWhich seven groups of nutrients does the body need?
FoundationWhich nutrient group is the main source of energy?
IntermediateWhat enzyme does saliva contain and what does it turn starch into?
IntermediateWhat are the two jobs of the hydrochloric acid in the stomach?
IntermediateWhat is the function of the villi in the small intestine wall?
ChallengeA food turns blue black when iodine solution is added. What does it contain?
ChallengeBenedict solution turns brick red after heating. What does the food contain?
ChallengeBiuret solution turns purple in a food sample. What does the food contain?
Error redoWhich statement is right? A: bile contains a fat digesting enzyme; B: bile emulsifies fat into small droplets.

03　Answers and one-line notes

#	Answer	One-line note
1	To break large food molecules into small nutrients that can be absorbed	Starch, protein and fat molecules are too large to cross the gut wall, so they must be broken down first.
2	Carbohydrates, proteins, fats, vitamins, minerals, dietary fibre and water	The first two and fat supply energy, while the rest build the body, regulate functions and help the gut.
3	Carbohydrates	Each gram of carbohydrate supplies about 4 kcal, and it is the largest part of most daily energy intake.
4	Salivary amylase, which breaks starch down into maltose	Chewing grinds the food while amylase starts chemical digestion, which is why rice tastes sweet if you chew it long enough.
5	It kills most bacteria taken in with food and provides the acidic conditions protein enzymes need	Gastric juice has a pH of about 2, and that acidity is required for the protein digesting enzyme to work.
6	They greatly increase the surface area so nutrients are absorbed faster	The villi also carry microvilli and a rich blood supply, so absorbed nutrients are carried away quickly.
7	Starch	Iodine turns blue black in the presence of starch, which makes it the standard starch test.
8	Reducing sugar, for example glucose	The reducing sugar turns the blue copper ions into a brick red precipitate of copper oxide.
9	Protein	Peptide bonds in protein react with the reagent to give a purple colour, which is the standard protein test.
10	B is right	Bile contains no enzyme at all; it only breaks large fat droplets into smaller ones so the fat enzyme can reach more surface.

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.