A Level H1 Biology Human Physiology Quiz

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A-Level Biology H1 Quiz - Human Physiology

Name: ___________________________
Class: ___________________________
Date: ___________________________
Score: _______ / 40

Duration: 50 minutes
Total Marks: 40
Topic: Human Physiology (Practice Quiz 1 of 5)

Instructions:

• Answer all 20 questions.
• Section A: Short structured questions (1–10). Section B: Data and figure interpretation (11–15). Section C: Applied and extended response (16–20).
• Write your answers in the spaces provided.
• Use pen. Show working where requested.

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Section A: Short Structured Questions (1–10)

1. State one function of the human trachea in the respiratory system. [1]

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2. Name the type of blood vessel that has a thick muscular wall and carries blood away from the heart. [1]

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3. Give one reason why haemoglobin is described as a conjugated protein. [1]

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4. State the term for the process by which oxygen moves from the alveoli into the blood capillaries. [1]

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5. The diagram below shows a section of the human heart.

Image pending generation: diagram for Q5.

Name the chamber labelled X that receives deoxygenated blood from the vena cava. [1]

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6. State the main nitrogenous waste product removed by the human kidney. [1]

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7. Give one role of bile salts in human digestion. [1]

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8. State the site of urine collection before it passes into the ureter in a nephron. [1]

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9. Name the blood cells responsible for transporting oxygen in humans. [1]

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10. State one way in which the wall of the alveolus is adapted for efficient gas exchange. [1]

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Section B: Data and Figure Interpretation (11–15)

11. Fig. 2 shows the partial pressure of oxygen ($pO_2$) in the lungs and in body tissues.

Image pending generation: graph for Q11.

Using Fig. 2, calculate the difference in $pO_2$ between alveoli and resting tissue. [2]

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12. With reference to Fig. 2, explain why oxygen diffuses from alveoli into the blood. [2]

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13. The table below shows systolic and diastolic blood pressure readings for four students.

Student	Systolic (mmHg)	Diastolic (mmHg)
A	118	76
B	135	88
C	145	95
D	110	70

State which student shows a reading consistent with stage 1 hypertension (systolic ≥ 140 or diastolic ≥ 90). [1]

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14. Fig. 3 shows a nephron and its associated blood vessels.

Image pending generation: diagram for Q14.

With reference to Fig. 3, describe how ultrafiltration occurs in the glomerulus. [3]

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15. The graph in Fig. 4 shows the concentration of glucose in the blood of a healthy person over 3 hours after a meal.

Image pending generation: graph for Q15.

Using Fig. 4, state the maximum blood glucose concentration recorded and the time at which it occurred. [2]

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Section C: Applied and Extended Response (16–20)

16. Explain how the structure of haemoglobin is related to its function in oxygen transport. [4]

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17. Describe the pathway of air from the nose to the alveoli, naming three structures in the pathway. [3]

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18. A person's erythrocytes were found to have defective spectrin proteins. Explain how this would affect the cell and its oxygen-carrying ability. [3]

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19. With reference to the principle of counter-current flow, explain how the human lung is efficient at gas exchange. [4]

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20. The table below shows the composition of blood plasma and filtrate at the start of the nephron.

Substance	Plasma (g/100 mL)	Filtrate (g/100 mL)
Glucose	0.10	0.10
Protein	7.00	0.00
Urea	0.03	0.03

Explain why protein is absent from the filtrate but glucose is present. [4]

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A-Level Biology H1 Quiz - Human Physiology (Answer Key)

Topic: Human Physiology
Version: 1 of 5
Total Marks: 40

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Section A Answers (1–10)

1. [1 mark]
Function: The trachea (windpipe) conducts air from the larynx to the bronchi / filters, warms, and moistens incoming air.
Teaching note: The trachea is part of the conducting airway; it is supported by cartilage rings to keep it open.

2. [1 mark]
Answer: Artery.
Teaching note: Arteries carry blood away from the heart under high pressure, hence thick muscular walls.

3. [1 mark]
Answer: It contains a non-protein group (haem / iron-containing prosthetic group) attached to globin protein.
Teaching note: Conjugated proteins have a prosthetic group; in haemoglobin it is haem with Fe²⁺.

4. [1 mark]
Answer: Diffusion.
Teaching note: Oxygen moves down its partial pressure gradient from alveolus (high $pO_2$) to capillary (low $pO_2$).

5. [1 mark]
Answer: Right atrium.
Expected visual: Fig.1 shows vena cava entering the right-side upper chamber. That chamber is the right atrium.
Teaching note: Deoxygenated blood from the body enters the right atrium via the vena cava.

6. [1 mark]
Answer: Urea.
Teaching note: Urea is produced in the liver from deamination of amino acids and excreted by kidneys.

7. [1 mark]
Answer: Emulsify fats / increase surface area for lipase action.
Teaching note: Bile salts break large fat droplets into smaller ones (emulsification).

8. [1 mark]
Answer: Renal pelvis (or Bowman's capsule is incorrect; urine collects in renal pelvis before ureter).
Teaching note: Filtrate becomes urine in collecting duct → renal pelvis → ureter.

9. [1 mark]
Answer: Red blood cells / erythrocytes.
Teaching note: Erythrocytes contain haemoglobin for O₂ transport.

10. [1 mark]
Answer: Wall is one cell thick (thin epithelium) / large surface area / moist surface.
Teaching note: Thin wall shortens diffusion distance.

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Section B Answers (11–15)

11. [2 marks]
Calculation:
Alveoli $pO_2$ = 100 mmHg
Resting tissue $pO_2$ = 40 mmHg
Difference = 100 − 40 = 60 mmHg.
Marking: 1 mark for correct values used, 1 mark for correct difference.
Teaching note: Diffusion depends on pressure gradient; larger difference drives faster diffusion.

12. [2 marks]
Answer: Oxygen diffuses from alveoli to blood because alveolar $pO_2$ (100 mmHg) is higher than blood $pO_2$ (~40 mmHg in tissue capillaries). Diffusion occurs down the partial pressure gradient.
Marking: 1 mark for referencing gradient, 1 mark for direction.
Teaching note: Gases move from high to low partial pressure.

13. [1 mark]
Answer: Student C (145/95).
Teaching note: Hypertension threshold systolic ≥140 or diastolic ≥90; only C meets it.

14. [3 marks]
Answer:

• Blood enters glomerulus via afferent arteriole (wider) and leaves via efferent arteriole (narrower), raising hydrostatic pressure. [1]
• High pressure forces water and small solutes (glucose, urea, ions) out of glomerular capillaries into Bowman's capsule. [1]
• Large proteins and cells remain in blood due to size barrier of capillary endothelium and basement membrane. [1]
  Teaching note: Ultrafiltration is pressure-driven, not energy-driven.

15. [2 marks]
Answer: Maximum = 8.0 mM at 1 hour.
Marking: 1 mark for value, 1 mark for time.
Expected visual: Fig.4 curve peaks at (1, 8.0).

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Section C Answers (16–20)

16. [4 marks]
Answer:

• Haemoglobin is a quaternary protein with 4 polypeptide chains (2 α, 2 β). [1]
• Each chain has a haem group with Fe²⁺ that binds one O₂ molecule, so one Hb carries 4 O₂. [1]
• It shows cooperative binding: binding of first O₂ changes shape to ease further binding. [1]
• Reversible binding allows O₂ uptake in lungs (high $pO_2$) and release in tissues (low $pO_2$). [1]
  Teaching note: Structure (multiple subunits + prosthetic groups) enables efficient transport and release.

17. [3 marks]
Answer: Nose → pharynx → larynx → trachea → bronchus → bronchiole → alveoli. (Any 3 structures named: e.g., pharynx, trachea, bronchus.) [1 each]
Teaching note: Air is filtered, warmed, moistened along pathway.

18. [3 marks]
Answer:

• Spectrin maintains erythrocyte biconcave shape and flexibility. [1]
• Defect causes fragile, spherical cells (spherocytosis) that may rupture (haemolysis). [1]
• Reduced cell count / destroyed cells lower haemoglobin amount, reducing O₂ capacity. [1]
  Teaching note: Shape is vital for passage through capillaries and surface area.

19. [4 marks]
Answer:

• Ventilation brings air with high $pO_2$ (100 mmHg) to alveoli continuously. [1]
• Blood in pulmonary capillaries has lower $pO_2$ (40 mmHg), maintaining gradient along whole capillary. [1]
• As blood moves, it always meets air with higher $pO_2$ (not equilibrated prematurely), so diffusion continues. [1]
• This counter-current-like maintenance of gradient maximises O₂ uptake. [1]
  Teaching note: In lungs it is actually cross-current, but gradient maintained along length improves efficiency.

20. [4 marks]
Answer:

• Glomerular filter allows small molecules (glucose, urea) through due to pore size. [1]
• Plasma proteins are large (≈7 g/100 mL, macromolecules) and cannot pass capillary wall / basement membrane. [1]
• Glucose is small and freely filtered, so present in filtrate at same concentration as plasma. [1]
• Proteins retained in blood maintain osmotic pressure; absence in filtrate confirms size selectivity. [1]
  Teaching note: Ultrafiltration is size-based; no protein in filtrate is normal.