Diseases and immunity
Cambridge IGCSE Biology (0610) · Unit 10: Diseases and immunity · 12 flashcards
Diseases and immunity is topic 10.1 in the Cambridge IGCSE Biology (0610) syllabus , positioned in Unit 10 — Diseases and immunity . In one line: A pathogen is a disease-causing organism. Examples include bacteria (like *Vibrio cholerae* causing cholera), viruses (like influenza), fungi (like athlete's foot), and protozoa (like *Plasmodium* causing malaria).
This topic is examined in Paper 1 (multiple-choice) and Papers 3/4 (theory), plus Paper 5 or Paper 6 (practical / alternative to practical). Past papers from 2022 to 2025 show this topic across 14 questions worth 170 marks (around 2.5% of all Biology marks in those years).
The deck below contains 12 flashcards — 5 definitions, 3 key concepts, 2 process cards and 2 application cards — covering the precise wording mark schemes reward. Use the 5 definition cards to lock down command-word answers (define, state), then move on to the concept and application cards to handle explain, describe and compare questions.
A pathogen
A pathogen is a disease-causing organism. Examples include bacteria (like *Vibrio cholerae* causing cholera), viruses (like influenza), fungi (like athlete's foot), and protozoa (like *Plasmodium* causing malaria).
What the Cambridge 0610 syllabus says
Official 2026-2028 specThese are the exact learning objectives Cambridge sets for this topic. Match the command word (Describe, Explain, State, etc.) in your answer to score full marks.
- Describe Describe a pathogen as a disease-causing organism
- Describe Describe a transmissible disease as a disease in which the pathogen can be passed from one host to another
- State State that a pathogen is transmitted: (a) by direct contact, including through blood and other body fluids (b) indirectly, including from contaminated surfaces, food, animals and air
- Describe Describe the body defences, limited to: skin, hairs in the nose, mucus, stomach acid and white blood cells
- Explain Explain the importance of the following in controlling the spread of disease: (a) a clean water supply (b) hygienic food preparation (c) good personal hygiene (d) waste disposal (e) sewage treatment (details of the stages of sewage treatment are not required)
- Describe Describe active immunity as defence against a pathogen by antibody production in the body Supplement
- State State that each pathogen has its own antigens, which have specific shapes Supplement
- Describe Describe antibodies as proteins that bind to antigens leading to direct destruction of pathogens or marking of pathogens for destruction by phagocytes Supplement
- State State that specific antibodies have complementary shapes which fit specific antigens Supplement
- Explain Explain that active immunity is gained after an infection by a pathogen or by vaccination Supplement
- Outline Outline the process of vaccination: (a) weakened pathogens or their antigens are put into the body (b) the antigens stimulate an immune response by lymphocytes which produce antibodies (c) memory cells are produced that give long-term immunity Supplement
- Explain Explain the role of vaccination in controlling the spread of diseases Supplement
- Explain Explain that passive immunity is a short-term defence against a pathogen by antibodies acquired from another individual, including across the placenta and in breast milk Supplement
- Explain Explain the importance of breast-feeding for the development of passive immunity in infants Supplement
- State State that memory cells are not produced in passive immunity Supplement
- Describe Describe cholera as a disease caused by a bacterium which is transmitted in contaminated water Supplement
- Explain Explain that the cholera bacterium produces a toxin that causes secretion of chloride ions into the small intestine, causing osmotic movement of water into the gut, causing diarrhoea, dehydration and loss of ions from the blood Supplement
Define a pathogen.
A pathogen is a disease-causing organism. Examples include bacteria (like *Vibrio cholerae* causing cholera), viruses (like influenza), fungi (like athlete's foot), and protozoa (like *Plasmodium* causing malaria).
What is a transmissible disease?
A transmissible disease is a disease in which the pathogen can be passed from one host to another. Examples include influenza, cholera, and athlete's foot. These diseases are spread through various means from an infected individual to a healthy one.
List three ways a pathogen can be transmitted indirectly.
Pathogens can be transmitted indirectly through contaminated surfaces (
Describe the role of skin in body defense.
Skin acts as a physical barrier, preventing pathogens from entering the body. It also produces oils and sweat which can inhibit the growth of some pathogens.
Explain the importance of a clean water supply in controlling disease spread.
A clean water supply prevents the spread of waterborne diseases like cholera, caused by the bacterium *Vibrio cholerae*. Ensuring water is free from pathogens reduces the risk of ingestion and subsequent infection.
Define active immunity.
Active immunity is a defence against a pathogen by antibody production in the body. It can occur after natural infection or through vaccination, resulting in long-term protection. An example is the body producing antibodies after contracting measles.
What are antigens, and what role do they play in immunity?
Antigens are molecules, often proteins, on the surface of pathogens, which have specific shapes. These shapes trigger an immune response, leading to antibody production.
Explain how antibodies work to fight pathogens.
Antibodies are proteins that bind to specific antigens on pathogens. This binding can directly destroy pathogens or mark them for destruction by phagocytes (white blood cells). Each antibody has a shape complementary to the shape of its antigen.
Outline the process of vaccination.
Vaccination involves introducing weakened pathogens or their antigens into the body. This stimulates lymphocytes to produce antibodies and memory cells, providing long-term immunity without causing the disease. An example is the MMR vaccine against measles, mumps, and rubella.
What is passive immunity, and how is it acquired?
Passive immunity is a short-term defence against a pathogen by antibodies acquired from another individual. This can occur across the placenta from mother to fetus or through breast milk.
Why is breastfeeding important for infant immunity?
Breastfeeding provides infants with passive immunity by transferring antibodies from the mother's milk to the baby. These antibodies protect the infant from infections during the first few months of life.
Explain how *Vibrio cholerae* causes diarrhoea and dehydration.
The *Vibrio cholerae* bacterium produces a toxin that causes chloride ions to be secreted into the small intestine. This leads to osmotic movement of water into the gut, causing diarrhoea, dehydration, and loss of ions from the blood.
Key Questions: Diseases and immunity
Define a pathogen.
A pathogen is a disease-causing organism. Examples include bacteria (like *Vibrio cholerae* causing cholera), viruses (like influenza), fungi (like athlete's foot), and protozoa (like *Plasmodium* causing malaria).
What is a transmissible disease?
A transmissible disease is a disease in which the pathogen can be passed from one host to another. Examples include influenza, cholera, and athlete's foot. These diseases are spread through various means from an infected individual to a healthy one.
Define active immunity.
Active immunity is a defence against a pathogen by antibody production in the body. It can occur after natural infection or through vaccination, resulting in long-term protection. An example is the body producing antibodies after contracting measles.
What are antigens, and what role do they play in immunity?
Antigens are molecules, often proteins, on the surface of pathogens, which have specific shapes. These shapes trigger an immune response, leading to antibody production.
What is passive immunity, and how is it acquired?
Passive immunity is a short-term defence against a pathogen by antibodies acquired from another individual. This can occur across the placenta from mother to fetus or through breast milk.
Cambridge syllabus keywords to use in your answers
These are the official Cambridge 0610 terms tagged to this section. Mark schemes credit responses that use the exact term — weave them into your answers verbatim rather than paraphrasing.
Key terms covered in this Diseases and immunity deck
Every term below is defined in the flashcards above. Use the list as a quick recall test before your exam — if you can't define one of these in your own words, flip back to that card.
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