AQA · GCSE · Combined Science

    Course version: 8464 · Version from Sept 2018

    Human defence systems: antibody production

    Antibodies are Y-shaped proteins made by white blood cells called lymphocytes.

    Checked against the AQA 8464 specification (opens in a new tab) on .

    • Point 10 of 11
    • 4 key terms

    Study notes

    From the checked teaching notes for this specification point.

    The idea

    Antibodies are Y-shaped proteins made by white blood cells called lymphocytes. Each antibody has binding sites whose shape is complementary to a specific antigen on a pathogen. When a lymphocyte meets its matching antigen, it divides and produces many copies of the same antibody, which bind to the antigens. This clumping immobilises pathogens and marks them for destruction by other white blood cells. Antibodies also give immunity: memory lymphocytes remain after an infection, so a later exposure triggers faster, larger antibody production. For example, after measles infection, measles-specific antibodies appear in the blood and prevent reinfection. Antibody production is a specific, adaptive response, unlike phagocytosis, which is non-specific.

    What earns the marks

    • Antibodies are proteins produced by lymphocytes (a type of white blood cell).
    • Each antibody has binding sites with a shape complementary to a specific antigen.
    • Binding of antibodies to antigens clumps pathogens and marks them for destruction by phagocytes.
    • Lymphocytes that recognise an antigen divide to produce many identical antibody molecules.
    • Memory lymphocytes allow faster, greater antibody production on a later exposure to the same antigen.

    Common mistakes and how to put them right

    • Saying antibodies kill pathogens directly.

      Put it right: Antibodies bind and clump pathogens, and phagocytes then ingest them.

    • Confusing antibodies with antibiotics.

      Put it right: Antibodies are proteins made by lymphocytes, whereas antibiotics are medicines that kill bacteria.

    • Stating that one antibody binds any antigen.

      Put it right: Antibody binding sites are complementary to one specific antigen shape.

    Exam tips

    • Use the word 'complementary' when linking antibody binding sites to antigen shape.
    • Name the white blood cell type as a lymphocyte rather than just 'white blood cell'.
    • Link antibody production to immunity by mentioning memory lymphocytes and a faster second response.

    Try the lesson

    The start of the Human defence systems: antibody production lesson, made from checked teaching notes for this specification point.

    Have a go first

    Which type of white blood cell produces antibodies?

    Listen

    Antibodies are Y-shaped proteins made by white blood cells called lymphocytes. Each antibody has binding sites whose shape is complementary to a specific antigen on a pathogen. When a lymphocyte meets its matching antigen, it divides and produces many copies of the same antibody, which bind to the antigens. This clumping immobilises pathogens and marks them for destruction by other white blood cells. Antibodies also give immunity: memory lymphocytes remain after an infection, so a later exposure triggers faster, larger antibody production. For example, after measles infection, measles-specific antibodies appear in the blood and prevent reinfection. Antibody production is a specific, adaptive response, unlike phagocytosis, which is non-specific. A strong answer earns marks for these points. Antibodies are proteins produced by lymphocytes (a type of white blood cell). Each antibody has binding sites with a shape complementary to a specific antigen. Binding of antibodies to antigens clumps pathogens and marks them for destruction by phagocytes. Lymphocytes that recognise an antigen divide to produce many identical antibody molecules. A common slip: Saying antibodies kill pathogens directly. Instead, antibodies bind and clump pathogens, and phagocytes then ingest them. Exam tip: Use the word 'complementary' when linking antibody binding sites to antigen shape.

    See it

    A flowchart running from top to bottom. The first box says a lymphocyte meets its matching antigen and points to a second box saying the lymphocyte divides. From the second box two arrows lead out. The first goes to a box saying many copies of the same antibody are produced, which leads to a box saying antibodies bind to antigens, which leads to a box saying pathogens clump, which leads to a final box saying marked for destruction by other white blood cells. The second arrow from the division box goes to a box saying memory lymphocytes remain, which leads to a final box saying later exposure gives faster, larger antibody production.
    It shows how a lymphocyte meeting its matching antigen leads to antibody production, clumping and destruction of pathogens, and memory lymphocytes giving faster antibody production on later exposure.

    Key words

    Say what each word means before you turn the card.

    Antigen-antibody binding

    Try answering aloud or in your head before turning the card.

    White blood cells and lymphocytes

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    Immunity and memory cells

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    Specific immune response

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    See every definition
    Antigen-antibody binding
    Binding sites on an antibody have a shape complementary to a specific antigen on a pathogen, and binding clumps pathogens and marks them for destruction.
    White blood cells and lymphocytes
    Antibodies are proteins produced by lymphocytes, which are a type of white blood cell.
    Immunity and memory cells
    Memory lymphocytes remain after an infection, so a later exposure to the same antigen triggers faster, larger antibody production.
    Specific immune response
    Antibody production is a specific, adaptive response, unlike phagocytosis, which is non-specific.

    Label the diagram

    Some boxes have lost their names. Pick the right name for each number.

    The diagram again, with 3 boxes numbered instead of named. A flowchart running from top to bottom. The first box says a lymphocyte meets its matching antigen and points to a second box saying the lymphocyte divides. From the second box two arrows lead out. The first goes to a box saying many copies of the same antibody are produced, which leads to a box saying antibodies bind to antigens, which leads to a box saying pathogens clump, which leads to a final box saying marked for destruction by other white blood cells. The second arrow from the division box goes to a box saying memory lymphocytes remain, which leads to a final box saying later exposure gives faster, larger antibody production.

    • 1Box 1

    • 2Box 2

    • 3Box 3

    0 of 3 labelled

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