NOV 06 Question 8 EITHER
a) Mosquitoes are VECTORS for malaria (meaning they can carry the disease in their bodies and pass it to humans). They are able to transmit malaria by sucking the blood of humans. When mosquitoes are feeding on humans, they will first pierce the skin and then inject their saliva (which contains an anti clotting agent so the blood doesn’t clot) so they can suck up liquid blood. However, the plasmodium (organism that causes malaria) is in the saliva, so it gets into the human’s blood also!
If you look at the answer scheme
You can answer it this way (using only easy points)
Mosquitoes are vectors of plasmodium which cause malaria (8th point, point is for plasmodium, not the term “malaria”), and pass it on by feeding on the blood (4th point) of an infected person, and then feeding on an uninfected person (10th point). The mosquito will pierce the skin of a person using their sharp mouthpart (5th point) and inject their saliva which contains an anti-clotting agent (7th point). In this way the plasmodium is introduced into the blood stream of the person. Total: 5 marks :)
Part (b)
Syphilis is an STD- caused by unprotected sex with a person who has the disease. If you look at your BIO notes I think it’s there? But very generalized which is enough.
Answer scheme
You can answer it this way (using only easy points)
Syphilis is a sexually transmitted disease spread through sexual contact (1st point) with a person who is infected with the bacterium that causes syphilis (2nd point). In the first stage of syphilis, sores will appear on the site of infection but will eventually disappear (3rd point- found in your Bio notes). In the second stage, rashes will appear all over the body and again will disappear after some time (4th point, also in your bio notes). In the third stage, organ failure and death may occur (6th point, also in your bio notes). All stages of syphilis can be treated with antibiotics (8th point)… Total: 6 marks (max is 5) :)
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