AQA GCSE Combined Science: Trilogy Biology Paper 1 (Foundation), 2022: Question 1

11 marks · Low Demand difficulty · Short Answer

Identify organs and enzymes of the digestive system, and describe food tests for protein, starch, and sugar.

Practise this question

Question

A multi-part exam question about the human digestive system. It includes a diagram of the human torso with labels A (mouth), B (liver), C (stomach), and D (small intestine). Questions ask to identify the stomach, the enzyme produced there, its pH, the organ producing bile, and the function of bile. A matching task links protein, starch, and sugar to reagents (Benedict's, Biuret, Iodine). A table shows food test results for a sample: Benedict's test is red, Biuret test is blue, and Iodine test is black.
Question text

01 Foods are digested before they are absorbed into the blood.

Figure 1 shows organs in the human digestive system.

Figure 1

01.1 Which organ is the stomach?

[1 mark]

Tick ( ) one box.

A B C D

01.2 What type of enzyme is produced in the stomach?

[1 mark]

Tick ( ) one box.

Carbohydrase

Lipase

Protease 3

01.3 Which term describes the pH in the stomach?

Give one reason why the stomach is this pH.

*02* [2 marks]

Tick ( ) one box.

Acidic

Alkaline

Neutral

Reason

01.4 Which organ produces bile?

[1 mark]

Tick ( ) one box.

Large intestine

Liver

Mouth

Pancreas 4

01.5 How does bile help in the digestion of foods?

[1 mark]

Tick ( ) one box.

It increases the surface area of fats.

It is an enzyme that digests protein.

It makes the pH in the small intestine acidic.

A student tested different foods for the presence of protein, starch and sugar.

01.6 Draw one line from each food molecule to the reagent used to test for the

food molecule.

[2 marks]

Food molecule Reagent

Benedict’s solution

Protein

Starch Biuret reagent

Sugar

5 Iodine solution

01.7 Give one safety precaution a student should take when using Benedict’s solution.

[1 mark]

01.8 Table 1 shows the results for one food sample.

Table 1

Test Benedict’s test Biuret test Iodine test

Colour after test Red Blue Black

Which of the tests show positive results?

[1 mark]

Tick ( ) one box.

All three tests

Benedict’s and Biuret tests only

Benedict’s and iodine tests only

Biuret and iodine tests only

01.9 Starch molecules are not absorbed into the blood from the digestive system.

Give one reason why.

[1 mark]

Mark scheme

Show the mark scheme The mark scheme for question 1. 01.1 is C. 01.2 is protease. 01.3 is acidic because it contains hydrochloric acid or is the optimum for protease. 01.4 is liver. 01.5 is it increases the surface area of fats. 01.6 shows lines connecting Protein to Biuret reagent, Starch to Iodine solution, and Sugar to Benedict's solution. 01.7 lists safety precautions like wearing goggles or using a water bath. 01.8 is Benedict's and iodine tests only. 01.9 states starch is too large or insoluble.

Question 1

AO /

Question Answers Extra information Mark

Spec. Ref.

01.1 C 1 AO1

4.2.1

4.2.2.1

AO /

Spec. Ref.

01.2 protease 1 AO1

Mark with 4.2.2.1

01.3

AO /

Spec. Ref.

01.3 acidic 1 AO1

Mark with

01.2 reason: 1 AO2

any one from:

• produces (hydrochloric) acid allow contains (hydrochloric) 4.2.2.1

acid 4.3.1.6

• optimum / best condition for allow optimum / best

enzyme / protease to act condition to digest food / protein

allow ecf from question 01.2

– OMBINED SCIENCE: TRIallow to kill microorganismLOGYs /– –

bacteria / pathogens

AO /

Spec. Ref.

01.4 liver 1 AO1

4.2.2.1

AO /

Spec. Ref.

01.5 it increases the surface area of 1 AO1

fats 4.2.2.1

AO /

Spec. Ref.

01.6 2 AO1

4.2.2.1

RPA3

all three correct for 2 marks

one or two correct for 1 mark

extra line from a box negates that box–OMBINED SCIENCE: TRILOGY – –

AO /

Spec. Ref.

01.7 any one from: 1 AO1

• wear goggles 4.2.2.1

• use a water bath to heat the RPA3

solution / mixture

• wash spills from bench / skin allow wash hands

allow wear gloves

ignore examples such as tie hair

back or move bags under bench

AO /

Spec. Ref.

01.8 Benedict’s and iodine tests only 1 AO3

4.2.2.1

RPA3

AO /

Spec. Ref.

01.9 any one from: 1 AO1

• starch (molecule) is (too) allow idea that starch needs to 4.2.2.1

large be broken down into small /

soluble molecules

• starch (molecule) is insoluble

Total Question 1 11

How to answer it

Human Digestion and Food Tests

What this question tests

This question assesses your ability to identify organs in the digestive system, recall the specific enzymes and conditions (pH) found in the stomach, understand the role of bile, and correctly identify reagents and safety protocols for food tests (Required Practical 3).

Parts 01.1, 01.2 & 01.3

The Stomach: Anatomy and Function

Correct Answers

  • 01.1: C (The stomach)
  • 01.2: Protease
  • 01.3: Acidic
  • Reason: Produces hydrochloric acid OR to provide the optimum pH for protease to work OR to kill microorganisms.

Key Knowledge

The stomach is a muscular bag that digests proteins. It produces hydrochloric acid, which gives it a low pH (around pH 2). This acidity is vital for killing bacteria on food and allowing protease enzymes (pepsin) to work at their fastest rate.

Total Marks: 4
Parts 01.4 & 01.5

Bile and the Liver

Correct Answers

  • 01.4: Liver
  • 01.5: It increases the surface area of fats.

Exam Technique

In 01.5, the process described is emulsification. Examiners look for the specific phrase "increases surface area." Avoid saying bile "digests" fat; only enzymes (lipase) can chemically digest fat.

Common Error

Many students confuse the Gallbladder (which stores bile) with the Liver (which produces it). Always check if the question asks for production or storage!

Total Marks: 2
Parts 01.6, 01.7 & 01.8

Food Tests (Required Practical)

01.6: Matching Reagents

  • Protein → Biuret reagent
  • Starch → Iodine solution
  • Sugar → Benedict's solution

01.7: Safety

Correct Answer: Wear goggles OR use a water bath to heat the solution (rather than a direct flame).

Examiner Tip: Benedict's test is the only one of these three that requires heating.

01.8: Interpreting Results

Correct Answer: Benedict's and iodine tests only.

Why? Table 1 shows Red for Benedict's (Positive for Sugar) and Black for Iodine (Positive for Starch). Biuret stayed Blue, which is a negative result for protein.

Total Marks: 4
Part 01.9

Absorption and Molecule Size

Key Knowledge

For a substance to be absorbed into the blood, it must be small and soluble so it can pass through the wall of the small intestine.

Correct Answer

Starch molecules are too large (or insoluble) to be absorbed.

Examiner Commentary

Top-level answers clearly state that starch is a "large molecule" that needs to be broken down into "small, soluble molecules" (like glucose) before absorption can occur. Simply saying "it's not the right shape" is usually not enough for the mark.

Total Marks: 1

Topics

Biology · B2: Organisation

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Biology Paper 1 (Foundation), 2022. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.