6ef5af","revisionId":"2eb38a3b-0feb-4883-8c17-3d61dbc0e0f6","questionNumber":null,"questionType":"LA","specification":"","difficulty":5,"difficultyBand":"medium","totalMarks":4,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"928c1a6b-51f2-4546-b55b-ff3047007d9a","label":null,"content":"Describe how lymphocytes (a type of white blood cell) defend the body against a specific viral infection.","markscheme":"- Lymphocytes recognize/detect specific antigens on the surface of the virus B1\n- They produce specific antibodies that are complementary in shape to these antigens B1\n- These antibodies bind to the antigens, clumping the viruses together (neutralizing them) or marking them for destruction by phagocytes B1\n- Memory cells are produced to ensure a faster immune response if the same virus enters the body again B1","marks":4,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"specific_immune_response","label":"Specific immune response","steps":[{"type":"text","order":1,"title":"Recognise the antigen","content":"A virus has **antigens** on its surface. An antigen is a molecule that the immune system can recognise as foreign.\n\nLymphocytes **recognise specific antigens on the surface of this virus**. “Specific” means each lymphocyte responds only to an antigen with the matching shape.\n\nThis identification point earns the first mark.","highlights":[{"text":"specific viral infection","location":"specification"}]},{"type":"text","order":2,"title":"Make matching antibodies","content":"The recognised antigen causes the lymphocyte to produce **specific antibodies**. Antibodies are proteins that attach to antigens.\n\nState that the antibodies are **complementary in shape** to the virus's antigens: their shapes fit together. This earns the second mark."},{"type":"text","order":3,"title":"Bind and remove viruses","content":"The specific antibodies **bind to the viral antigens**. This can neutralise the viruses by clumping them together, or mark them so phagocytes can destroy them.\n\nA **phagocyte** is a white blood cell that engulfs and digests pathogens. Giving either valid outcome after antibody binding earns the third mark."},{"type":"text","order":4,"title":"Leave memory cells","content":"Some lymphocytes become **memory cells**. They remain in the body after the infection has been dealt with.\n\nIf the **same virus** enters again, memory cells allow a faster immune response. This earns the final mark; do not merely say “the body becomes immune” without explaining the role of memory cells.","highlights":[{"text":"specific viral infection","location":"specification"}]}]}],"generatedAt":"2026-07-22T08:51:38.429Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"3d377b80-e88e-4fc2-aa1a-2feefa01c7b5","revisionId":"dcb5f158-96f0-4954-a86f-3924d6e7aea9","questionNumber":null,"questionType":"LA","specification":"","difficulty":4,"difficultyBand":"medium","totalMarks":3,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"9defd273-27fa-4e7c-8976-0330e1528ab0","label":null,"content":"*Corynebacterium diphtheriae* is a bacterium that causes the serious infection diphtheria. Children are routinely vaccinated against diphtheria. Explain why a vaccinated child does not become ill if the *Corynebacterium diphtheriae* bacteria enter their body at a later date.","markscheme":"- White blood cells (specifically memory cells) recognise the specific antigen on the bacteria B1\n- Memory cells rapidly produce a large quantity of specific antibodies M1\n- Antibodies destroy the bacteria (or neutralise toxins) before they can multiply and cause symptoms or illness A1","marks":3,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"immune_memory_response","label":"Immune memory response","steps":[{"type":"text","order":1,"title":"Recognise the antigen","content":"The vaccination has already left **memor

Plant defences and the human immune system

Question 6

Plant defences and the human immune system Questions

Plant defences and the human immune system

Question 6

Plant defences and the human immune system Questions