Diseases and immunity — IGCSE Biology (0970) questions by topic

Diseases and immunity questions distinguish direct from indirect pathogen transmission, interpret a diagram of an immune mechanism destroying a pathogen, define what makes a disease transmissible, and identify which body defences, such as stomach acid or white blood cells, protect against pathogens in food.

Choose, identify, state, calculate and explain span 1 to 14 marks across 24 real questions from 2023 to 2025 papers. Because transmission routes and immune mechanisms are easily conflated under time pressure, submitting each answer for instant marking flags the specific confusion, such as direct versus indirect spread, before it affects related questions.

May–June 2025, Paper 11

Question 24 · 1 mark

Which type of pathogen transmission is by direct contact? A contaminated air B contaminated blood C contaminated food D contaminated surfaces

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May–June 2025, Paper 12

Question 19 · 1 mark

How can the spread of disease be prevented? A leaving food uncovered B only washing hands after meals C using the same equipment to prepare raw and cooked food D washing hands…

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May–June 2025, Paper 21

Question 16 · 1 mark

The diagram shows what happens in the body during active immunity. pathogens enter the body → W are detected → lymphocytes become active, leading to three outcomes: X destroy…

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Question 17 · 1 mark

Cholera is a disease caused by a bacterium called Vibrio cholerae which produces a toxin in the infected person's gut. What is the effect of this toxin? A The toxin causes loss of…

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May–June 2025, Paper 22

Question 19 · 1 mark

Three statements about immunity are listed. 1 The transfer of antibodies from mother to baby in breast milk is an example of passive immunity. 2 Passive immunity results in…

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May–June 2025, Paper 32

Question 3 · 12 marks

Pathogens are disease-causing organisms. Describe how gastric juice in the stomach helps to defend the body against pathogens in food.

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May–June 2024, Paper 11

Question 24 · 1 mark

What is a direct way of transmitting a pathogen? A by contact with contaminated air B by contact with contaminated blood C by contact with contaminated food D by contact with…

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Question 30 · 1 mark

The graph shows the number of cases of MRSA in one country between 2001 and 2006. Between which years was the greatest change in the number of cases of MRSA? A 2002 and 2003 B…

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May–June 2024, Paper 12

Question 22 · 1 mark

Which method of pathogen transmission is direct? A breathing in pathogens in air B eating contaminated food C transfusing contaminated blood D touching a door handle that has…

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Question 32 · 1 mark

What is HIV? A a bacterium B an enzyme C a pathogen D an antibody

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May–June 2024, Paper 21

Question 21 · 1 mark

One of the symptoms of the disease cholera is diarrhoea. This is due to water loss by osmosis caused by the cholera toxin. What is the effect of cholera toxins that results in…

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Question 22 · 1 mark

Which statement about immunity is correct? A A part of the antibody molecule has the same shape as the antigen it acts on. B Babies develop passive immunity from the antibodies…

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May–June 2024, Paper 22

Question 20 · 1 mark

The cholera bacterium produces a toxin which affects humans. What is an effect of this toxin on the human body? A the secretion of chloride ions from the blood into the lumen of…

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May–June 2024, Paper 31

Question 4 · 9 marks

Symptoms of the disease influenza may include sneezing. Fig. 4.1 shows a sign at a hospital reading 'Always wash hands after sneezing'. Explain why washing your hands after…

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May–June 2024, Paper 41

Question 6 · 14 marks

Polio is a viral disease that can cause nerve damage in humans. In one area, polio vaccination began in 1957. Fig. 6.1 shows the number of cases of polio in this area between 1950…

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October–November 2024, Paper 12

Question 35 · 1 mark

Some ways that diseases can be transmitted are listed. 1 airborne droplets 2 blood and needles 3 food and drink 4 unprotected sex Which ways can transmit HIV?

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October–November 2024, Paper 22

Question 20 · 1 mark

Which features of the human body protect against pathogens in food? red blood cells stomach acid white blood cells --- --- --- --- A yes yes no B yes no no C no yes yes D no no yes

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May–June 2023, Paper 11

Question 21 · 1 mark

What is an example of good personal hygiene in the kitchen? A cooking food at a high temperature B disposing of waste food in sealed containers C storing uncooked meat in a fridge…

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Question 30 · 1 mark

Which statements about antibiotics are correct? 1 Antibiotics can be used to treat bacterial infections. 2 Antibiotics can be used to treat viral infections. 3 Antibiotics are not…

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May–June 2023, Paper 12

Question 29 · 1 mark

The table shows which antibiotics (numbered 1–6) are effective against different types of bacteria (MRSA, Streptococcus, Pseudomonas, Anaerobes); shaded areas show the antibiotic…

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May–June 2023, Paper 21

Question 19 · 1 mark

The cholera bacterium toxin causes dehydration and loss of salts from the blood in humans. Which statement explains the reason for this? A Chloride ions are secreted into the…

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May–June 2023, Paper 22

Question 19 · 1 mark

Cholera bacteria in the gut cause secretion of chloride ions which leads to diarrhoea. Diagrams A–D show the movement of chloride ions (Cl–) and water (H2O) between the gut and…

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October–November 2023, Paper 12

Question 20 · 1 mark

Which statement describes a transmissible disease? A a disease caused when a pathogen passes from one host to another B a disease caused when a pathogen passes through a host's…

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October–November 2023, Paper 22

Question 20 · 1 mark

When a pathogen enters the blood, the immune system uses different mechanisms to destroy the pathogen. The diagram shows one of these mechanisms, with structures X and Y and a…

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