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Innate Immunity Quiz
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Which statement best describes a defining property of the innate immune system?
- A It produces antibodies as its primary effector mechanism You picked ✕
- B It provides a rapid, non-specific defence that lacks immunological memory You picked ✓
- C It generates highly specific responses that improve on repeated exposure You picked ✕
- D It responds slowly but confers long-lasting protection after infection You picked ✕
- E It requires clonal expansion of lymphocytes before becoming effective You picked ✕
Correct!
Incorrect
The answer is B: It provides a rapid, non-specific defence that lacks immunological memory
Explanation
Why B is correct
See Properties of the Innate Immune System. Option B is correct. The innate immune system is the front-line defence against any pathogen (a microbe that can cause disease). It is called non-specific because it responds equally to anything that is non-self (not made by the body), recognising broad molecular patterns shared by whole groups of microbes rather than the unique markers, or antigens, of one organism. Its parts are already in place before infection, such as skin, mucus, phagocytes (cells that engulf microbes), complement and cytokines (chemical messenger proteins), so it acts within minutes to hours. Because it does not adapt after an infection it has no immunological memory: a second encounter with the same microbe is met with essentially the same response as the first. The adaptive system is the contrast. It is slow to start, specific for one antigen, long lasting and has memory, which is why vaccines work by training it. In short, innate immunity is fast, non-specific, standardised and forgetful.
- Speed: Innate immunity is the front-line defence and acts within minutes to hours.
- Specificity: It is non-specific, recognising broad patterns shared by whole groups of microbes.
- Memory: It has no immunological memory, so a second encounter gets essentially the same response.
Why the other options are incorrect
- A. It produces antibodies as its primary effector mechanism: Antibodies are made by plasma cells (activated B lymphocytes) and are the main weapon of the adaptive system. The innate system relies on barriers, phagocytes, complement and cytokines. Your answer
- C. It generates highly specific responses that improve on repeated exposure: Specific responses that improve on repeated exposure describe adaptive immunity, which remembers antigens it has met before. The innate system responds the same way every time. Your answer
- D. It responds slowly but confers long-lasting protection after infection: A slow response with long-lasting protection describes adaptive immunity, which needs time to develop. Innate immunity is the opposite: fast and short-lived, with no lasting memory. Your answer
- E. It requires clonal expansion of lymphocytes before becoming effective: Clonal expansion means selected lymphocytes multiplying into an army of identical cells, which takes days. The innate system works at once without waiting for that. Your answer
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More questions from this set. Start the quiz to answer them and see each explanation.
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1
Which of the following is a protective role of the body's normal flora as part of innate immunity?
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2
Which mechanism best explains how opsonisation enhances the phagocytosis of bacteria by innate immune cells?
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