AQA A-Level Biology Paper 1, November 2021: Question 4

6 marks · Medium difficulty · Short Answer

Suggest improvements for a scientific drawing of dissected blood vessels, identify vessel types and features from a drawing, and state safety precautions for clearing away after a mammalian organ dissection.

Practise this question

Question

An exam question with three parts based on a dissection of a mammalian organ. Figure 4 shows a photograph of a sliced organ with labels pointing to blood vessel X and blood vessel Y. Figure 5 shows a student's line drawing of these two blood vessels. Question 04.1 asks for two ways to improve the quality of the drawing (2 marks). Question 04.2 asks to identify blood vessels X and Y and describe one identifying feature (2 marks). Question 04.3 asks for two precautions when clearing away after dissection (2 marks).
Question text

04 A student dissected an organ from a mammal to observe blood vessels.

He dissected a slice of the organ and identified two blood vessels.

Figure 4 shows a photograph of his dissection.

Figure 4

Figure 5 shows a drawing of the blood vessels from his dissection.

Figure 5

04.1 Suggest two ways the student could improve the quality of his scientific drawing of the

blood vessels in this dissection.

[2 marks]

*0124.*2 Identify the type of blood vessel labelled as X and the type of blood vessel labelled as

Y in Figure 4.

Describe one feature that allowed you to identify the blood vessels.

[2 marks]

Blood vessel X

Blood vessel Y

Feature

04.3 Describe two precautions the student should take when clearing away after the

dissection.

[2 marks]

Mark scheme

Show the mark scheme The mark scheme provides guidance for answering questions 04.1, 04.2, and 04.3. For 04.1, acceptable answers include using single continuous lines, adding labels/annotations/title, scale bar, etc. For 04.2, blood vessel X is identified as an artery/arteriole and Y as a vein/venule, with distinguishing features such as lumen size or wall thickness. For 04.3, safety measures such as safe handling of sharp instruments, disinfecting surfaces or hands, and proper disposal of biological material are required.

Question Marking Guidance Mark Comments

1. Only use single lines/do not use sketching

04.1

(lines)/ensure lines are continuous/connected;

2. Add labels/annotations/title;

2 max

3. Add magnification/scale (bar);

4. Draw all parts to same scale/relative size;

5. Do not use shading/hatching;

04.2 1. Blood vessel X – artery/arteriole and Ignore name of blood

vessel, eg.

Blood vessel Y – vein/venule;

(pulmonary) artery

2. (Difference in) lumen size

OR

(Difference in) wall thickness;

04.3 1. Carry/wash sharp instruments by holding handle 1. and 2. Accept for

‘instruments’, a

OR

suitable named

Carry/wash sharp instruments by pointing away example, eg. scalpel

(from body)/down;

2. and 3. Accept for

2. Disinfect instruments/surfaces; ‘disinfect’, sanitise OR

use antiseptic

3. Disinfect hands 2 max

OR

Wash hands with soap (and water);

4. Put organ/gloves/paper towels in a (separate)

bag/bin/tray to dispose;

How to answer it

Mammalian Dissection & Blood Vessel Identification Study Guide

What this question tests

This question assesses your practical biology skills, specifically focusing on biological drawing rules, histological identification of blood vessels based on structural adaptations (lumen size and wall thickness), and safe laboratory clearance procedures following a dissection.

Question 04.1 [2 marks]

Improving Scientific Drawings

✅ Correct Answers (Any 2 of the following)

  • Only use single lines / do not use sketching lines / ensure lines are continuous and connected.
  • Add labels, annotations, or a title.
  • Add a magnification or scale bar.
  • Draw all parts to the same scale / correct relative size.
  • Do not use shading or hatching.

❌ Common Errors

  • Using sketchy, broken pencil strokes instead of a single, firm, continuous line.
  • Adding cross-hatching or stippling (shading) to represent wall thickness, which is strictly forbidden in biological scientific drawings.
  • Omitting labels or scale bars, losing easy AO3 marks.
Mark allocation: 2 marks max for any two valid biological drawing improvements listed above.
Question 04.2 [2 marks]

Identifying Blood Vessels & Structural Features

✅ Correct Answers

Blood vessel X: Artery (accept arteriole)

Blood vessel Y: Vein (accept venule)

Identifying Feature (Choose one):

  • Difference in lumen size (Artery has a smaller lumen; vein has a larger lumen).
  • Difference in wall thickness (Artery has a thicker wall; vein has a thinner wall).

🧠 Exam Technique & Knowledge

When identifying blood vessels in cross-section, always look at the proportional thickness of the tunica media (muscle/elastic layer) and the size of the central lumen. Arteries must withstand high pressure from ventricular systole, hence their thick muscular/elastic walls and small, rounded lumens. Veins carry blood under low pressure back to the heart, resulting in collapsed or wide, irregular lumens with thin walls.

Mark allocation: 1 mark for correctly identifying both X and Y. 1 mark for describing a valid contrasting structural feature.
Question 04.3 [2 marks]

Safe Laboratory Clearance Procedures

💡 Key Knowledge & Correct Answers

To score full marks, state two clear safety precautions taken when cleaning up after a biological dissection:

  • Carry or wash sharp instruments (e.g., scalpels) by holding the handle, or pointing sharp edges away from the body / downwards.
  • Disinfect instruments and work surfaces.
  • Disinfect hands or wash hands thoroughly with soap and water.
  • Place biological tissue, gloves, or contaminated paper towels into a separate designated waste bag/bin/tray.

❌ Common Errors

Vague answers like "clean up properly" or "be careful with the knife" do not gain credit. Examiners require specific procedural actions: how to hold instruments, what to use for cleaning (disinfectant/soap), and where to dispose of biological waste.

Mark allocation: 2 marks max for any two valid safety precautions clearly explained.

Topics

Biology · Practical skills · Required Practicals · 3.3 Organisms exchange substances with their environment · Experimental design · AS practicals (1–6)

Question and mark scheme from the AQA A-Level Biology examination, Paper 1, November 2021. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.