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Disease and Immunity Flashcards
Free GCSE and A Level Biology Revision Cards
Work through the body's defences against pathogens, from phagocytosis and antibody production to vaccination and monoclonal antibodies. Free Biology flashcards for GCSE and A Level students.
Question
What is a pathogen?
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Answer
A microorganism (bacterium, virus, fungus, or protist) that causes disease in a host organism.
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Question
How do bacteria cause disease?
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Answer
By reproducing rapidly inside the host and releasing toxins that damage cells and tissues or disrupt normal body functions.
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Question
How do viruses cause disease?
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Answer
By invading host cells, hijacking cellular machinery to replicate, and then lysing (bursting) the host cells as they release new virus particles.
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Question
What are the non-specific defences of the human body?
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Answer
Skin (physical barrier), mucus and cilia (trap pathogens in the respiratory tract), stomach acid (kills pathogens), and inflammatory response.
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Question
What is phagocytosis?
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Answer
A non-specific immune response where phagocytes (neutrophils and macrophages) engulf and digest pathogens using enzymes.
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Question
What is the difference between B cells and T cells?
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Answer
B cells produce antibodies (humoral immunity). T cells either kill infected cells directly (cytotoxic T cells) or coordinate the immune response (helper T cells).
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Question
What is an antigen?
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Answer
A molecule (usually protein) on the surface of a pathogen or cell that is recognised as foreign by the immune system, triggering an immune response.
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Question
What is an antibody?
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Answer
A Y-shaped protein produced by B cells that binds specifically to a complementary antigen, neutralising pathogens or marking them for destruction.
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Question
What is immunological memory?
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Answer
After infection, memory B and T cells persist in the body. On re-exposure to the same pathogen, they mount a faster, larger secondary immune response, preventing illness.
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Question
How do vaccines work?
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Answer
They introduce a weakened/killed pathogen, antigen, or mRNA to stimulate the immune system to produce antibodies and memory cells — without causing disease.
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