IGCSE Biology Topic 10: Diseases and Immunity MCQs – 30 Practice Questions with Answers (Cambridge 0610)
Free practice for Cambridge IGCSE Biology 0610 on diseases and immunity, covering pathogens, body defences, antibodies, vaccination and cholera, with every question followed by a worked explanation.
Pathogens and how diseases spread
Q1. Which description best fits a pathogen?
- (A) An organism that always lives harmlessly inside another organism
- (B) A disease-causing organism
- (C) A chemical made by the body to fight infection
- (D) A type of white blood cell
Show Answer
Answer: B – A pathogen is defined as an organism that causes disease in its host.
Q2. What makes a disease a transmissible disease?
- (A) It is caused by a faulty gene passed from parent to child
- (B) It affects only one organ of the body
- (C) It is caused by a shortage of one nutrient in the diet
- (D) Its pathogen can be passed from one host to another
Show Answer
Answer: D – A transmissible disease is one in which the pathogen spreads from host to host.
Q3. Which of these is an example of direct transmission of a pathogen?
- (A) Contact with infected blood
- (B) Touching a surface left contaminated by an infected person
- (C) Eating food that has been contaminated
- (D) Breathing in air carrying a pathogen
Show Answer
Answer: A – Transmission by direct contact includes spread through blood and other body fluids.
Q4. Which of these is an example of indirect transmission of a pathogen?
- (A) A pathogen passed in blood during direct contact
- (B) A pathogen passed in body fluid during direct contact
- (C) A pathogen picked up from a contaminated surface
- (D) A pathogen passed by direct skin-to-skin contact
Show Answer
Answer: C – Indirect transmission includes spread from contaminated surfaces, food, animals and air.
Q5. Which pair of routes are both indirect routes of transmission?
- (A) Blood and other body fluids passed during direct contact
- (B) Contaminated food and contaminated air
- (C) Direct contact and infected blood
- (D) Body fluids and direct contact
Show Answer
Answer: B – Contaminated food and contaminated air are both indirect routes, as are contaminated surfaces and animals.
Q6. How does the skin act as a body defence?
- (A) It forms a barrier that stops pathogens entering the body
- (B) It produces antibodies against specific pathogens that land on it
- (C) It filters pathogens out of the blood
- (D) It traps pathogens in sticky fluid
Show Answer
Answer: A – Intact skin blocks the entry of pathogens, acting as a physical barrier.
Q7. What is the defensive role of the hairs in the nose?
- (A) They produce acid that kills swallowed pathogens
- (B) They make antibodies against inhaled pathogens
- (C) They filter pathogens out of the blood
- (D) They trap dust and microbes entering with inhaled air
Show Answer
Answer: D – Hairs in the nose trap particles and microbes before they can travel further into the airways.
Q8. What is the defensive role of mucus?
- (A) It dissolves pathogens using strong acid
- (B) It carries antibodies around the body in the blood to infected tissues
- (C) It traps pathogens so they cannot reach body tissues
- (D) It engulfs pathogens and digests them
Show Answer
Answer: C – Mucus traps pathogens on moist linings, preventing them from invading deeper tissues.
Q9. How does stomach acid help to defend the body?
- (A) It kills many pathogens that are swallowed with food or drink
- (B) It produces memory cells against gut pathogens so later infections are fought faster
- (C) It traps pathogens in the lining of the stomach
- (D) It carries white blood cells to the gut wall
Show Answer
Answer: A – The acid conditions in the stomach destroy many pathogens before they can cause infection.
Q10. Which cells form part of the body’s defences against pathogens that have entered the body?
- (A) Red blood cells
- (B) White blood cells
- (C) Platelets
- (D) Muscle cells
Show Answer
Answer: B – White blood cells defend the body, including by engulfing pathogens and producing antibodies.
Body defences and antibodies
Q11. What is an antigen?
- (A) A protein made by white blood cells to destroy pathogens in the blood
- (B) A cell that engulfs invading microbes
- (C) A chemical that kills pathogens in the stomach
- (D) A substance on a pathogen with a shape the immune system recognises
Show Answer
Answer: D – Each pathogen carries its own antigens, which have specific shapes that the immune system can recognise.
Q12. What are antibodies?
- (A) Cells that engulf pathogens whole
- (B) Chemicals that dissolve the skin barrier
- (C) Proteins that bind to antigens
- (D) Pathogens weakened for use in vaccines
Show Answer
Answer: C – Antibodies are proteins that bind to the antigens of a pathogen.
Q13. Why does a particular antibody act against only one type of pathogen?
- (A) Its shape is complementary to one specific antigen shape
- (B) It is too large to pass through the walls of blood vessels to reach other pathogens
- (C) It is only made in one part of the body
- (D) It is destroyed as soon as it binds any antigen
Show Answer
Answer: A – Specific antibodies have complementary shapes that fit specific antigens, like a key fitting one lock.
Q14. After an antibody binds to an antigen, what can happen to the pathogen?
- (A) It always becomes harmless at once with no further action needed
- (B) It may be destroyed directly or marked for destruction by phagocytes
- (C) It is carried out of the body in the urine unchanged
- (D) It is converted into a memory cell
Show Answer
Answer: B – Antibody binding leads to direct destruction of pathogens or marks them for destruction by phagocytes.
Q15. What do phagocytes do to pathogens marked by antibodies?
- (A) They produce more antigens on the pathogen surface
- (B) They trap pathogens in mucus
- (C) They stop the pathogen reproducing by blocking the skin
- (D) They engulf and destroy the marked pathogens
Show Answer
Answer: D – Phagocytes are white blood cells that engulf and digest pathogens, including those marked by antibodies.
Active and passive immunity, vaccination and cholera
Q16. What is active immunity?
- (A) Protection gained by receiving antibodies from another person
- (B) Protection from a barrier such as the skin
- (C) Defence against a pathogen by antibody production in the body
- (D) Protection gained by washing hands and handling food hygienically
Show Answer
Answer: C – In active immunity the person’s own body produces antibodies against the pathogen.
Q17. How can a person gain active immunity?
- (A) After an infection by a pathogen or by vaccination
- (B) Only by receiving antibodies in breast milk
- (C) Only by receiving antibodies across the placenta
- (D) Only by treatment after the disease has started
Show Answer
Answer: A – Active immunity is gained after infection by a pathogen or by vaccination.
Q18. What is put into the body during vaccination?
- (A) Fully active pathogens in large numbers
- (B) Weakened pathogens or their antigens
- (C) Ready-made antibodies from another person
- (D) Memory cells taken from an immune person
Show Answer
Answer: B – Vaccination introduces weakened pathogens or their antigens, which cannot cause the full disease.
Q19. During vaccination, which cells produce antibodies in response to the antigens?
- (A) Red blood cells
- (B) Platelets
- (C) Muscle cells
- (D) Lymphocytes
Show Answer
Answer: D – The antigens stimulate an immune response by lymphocytes, which produce antibodies.
Q20. Why does vaccination give long-term protection?
- (A) The weakened pathogens stay active in the body for life
- (B) Antibodies from the vaccine are passed to other people
- (C) Memory cells are produced that give long-term immunity
- (D) The skin barrier becomes permanently thicker
Show Answer
Answer: C – Vaccination leads to memory cells, so a later encounter with the real pathogen triggers a fast, strong response.
Q21. How does vaccination help to control the spread of a disease in a population?
- (A) It reduces the number of people who can catch and pass on the pathogen
- (B) It kills pathogens already present in drinking water supplies across the whole area
- (C) It replaces the need for sewage treatment
- (D) It makes contaminated food safe to eat
Show Answer
Answer: A – When fewer people are susceptible, the pathogen finds fewer hosts and spreads less easily.
Q22. What is passive immunity?
- (A) Long-term defence following vaccination
- (B) Defence by the skin and mucus barriers
- (C) Defence by memory cells made after infection, lasting for many years
- (D) Short-term defence by antibodies acquired from another individual
Show Answer
Answer: D – Passive immunity is a short-term defence using antibodies that come from another individual.
Q23. By which two routes can a baby naturally receive antibodies from its mother?
- (A) Through the skin and through the nose hairs
- (B) Across the placenta and in breast milk
- (C) Through vaccination and through infection
- (D) Through contaminated water and through food
Show Answer
Answer: B – Passive immunity includes antibodies passed across the placenta and antibodies present in breast milk.
Q24. Why is breast-feeding important for the development of passive immunity in infants?
- (A) It gives the infant memory cells that protect it for the whole of its life
- (B) It thickens the infant’s skin barrier
- (C) It supplies the infant with antibodies from the mother
- (D) It produces stomach acid in the infant
Show Answer
Answer: C – Breast milk carries maternal antibodies, giving the infant short-term passive protection.
Q25. Why does passive immunity not last as long as active immunity?
- (A) No memory cells are produced in passive immunity
- (B) No antibodies are involved in passive immunity
- (C) The antibodies attack the body’s own cells
- (D) The skin barrier breaks down during passive immunity
Show Answer
Answer: A – Because memory cells are not produced, the borrowed antibodies are eventually lost and protection fades.
Q26. What causes cholera, and how is it transmitted?
- (A) A virus transmitted by direct contact with blood
- (B) A fungus transmitted through contaminated air
- (C) A bacterium transmitted by insect bites
- (D) A bacterium transmitted in contaminated water
Show Answer
Answer: D – Cholera is caused by a bacterium that is transmitted in contaminated water.
Q27. In cholera, what does the bacterial toxin cause in the small intestine?
- (A) Blockage of the airway by mucus
- (B) Secretion of chloride ions into the small intestine
- (C) Production of antibodies in the gut wall
- (D) Thickening of the intestinal wall so water cannot pass
Show Answer
Answer: B – The cholera bacterium produces a toxin that causes chloride ions to be secreted into the small intestine.
Q28. After chloride ions are secreted into the gut in cholera, what happens next?
- (A) Water is absorbed rapidly from the gut into the blood
- (B) The gut stops absorbing all nutrients permanently
- (C) Water moves into the gut by osmosis, causing diarrhoea
- (D) Blood cells move into the gut to destroy the toxin
Show Answer
Answer: C – The secreted ions draw water into the gut by osmosis, producing watery diarrhoea.
Q29. Which serious effects can follow the diarrhoea caused by cholera?
- (A) Dehydration and loss of ions from the blood
- (B) A permanent rise in blood volume
- (C) Extra water stored in the muscles
- (D) A lasting increase in antibody production
Show Answer
Answer: A – Severe water loss leads to dehydration and to ions being lost from the blood.
Q30. Which control measures most directly reduce the spread of cholera?
- (A) Good personal hygiene alone, with no change to water supplies
- (B) Hygienic food preparation alone, with no change to water supplies
- (C) Waste disposal alone, with no change to water supplies
- (D) A clean water supply together with sewage treatment
Show Answer
Answer: D – A clean water supply and sewage treatment cut off the contaminated-water route, alongside hygiene, safe food preparation and waste disposal.
Revise any questions you missed, especially the difference between active and passive immunity, then retest yourself on the cholera sequence.