Type of immunity How antibodies are obtained Example Active natural body makes antibodies after an infection recovering from measles Active artificial havin...
Question 1 Report
| Type of immunity | How antibodies are obtained | Example |
|---|---|---|
| Active natural | body makes antibodies after an infection | recovering from measles |
| Active artificial | having the MMR vaccine | |
| Passive natural | antibodies passed from the mother | |
| Passive artificial | antibodies injected into the body | an injection of anti-venom |
The body defends itself against disease-causing organisms using its immune system, which can provide immunity in different ways. Immunity may be active or passive, and each of these can arise naturally or artificially. The table classifies four types of immunity, but two cells have been left blank.
(a) Define the term pathogen. [1]
(b) Complete the table by describing how antibodies are obtained in active artificial immunity. [2]
(c) Complete the table by giving one example of passive natural immunity. [1]
(d) Describe the difference between active and passive immunity in terms of how long the protection lasts. [3]
(e) Explain why active immunity provides longer-lasting protection than passive immunity. [4]
(f) State what is meant by an antigen. [1]
(g) Suggest why a newborn baby benefits from passive immunity. [2]
Answer Details
(a) A pathogen is an organism (microorganism) that causes disease [1].
(b) In active artificial immunity, antibodies are obtained because the body makes its own antibodies [1] after a vaccine containing antigens (a weakened/dead pathogen or its antigens) is given [1].
(c) An example of passive natural immunity is antibodies passed from mother to baby through breast milk (or across the placenta) [1]. The completed table therefore reads:
| Type of immunity | How antibodies are obtained | Example |
|---|---|---|
| Active natural | body makes antibodies after an infection | recovering from measles |
| Active artificial | body makes antibodies after a vaccine with antigens is given | having the MMR vaccine |
| Passive natural | antibodies passed from the mother | antibodies in breast milk / across the placenta protecting a baby |
| Passive artificial | antibodies injected into the body | an injection of anti-venom |
(d) On how long protection lasts: active immunity lasts a long time and may be lifelong [1]; passive immunity is short-lived / temporary [1]; the difference is that only in active immunity does the body itself keep making or renewing the antibodies [1].
(e) Active immunity lasts longer because in it the body makes its own antibodies [1]; memory cells are produced [1]; these memory cells remain in the blood long-term [1]; so on re-infection antibodies can be made quickly and in large amounts again [1]. In passive immunity no memory cells are made, and the received antibodies are broken down, so protection soon ends.
(f) An antigen is a molecule / marker (on the surface of a pathogen) that the immune system recognises as foreign [1].
(g) A newborn benefits from passive immunity because its own immune system is not yet fully developed and cannot make enough antibodies [1], so the ready-made antibodies from the mother protect it against infection during early life [1].
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