Qualification > Sciences
IGCSE Biology Paper 3
girl_92:
--- Quote from: hash094 on June 09, 2009, 01:14:25 pm ---
--- Quote from: madee on June 09, 2009, 01:12:54 pm ---
--- Quote from: hash094 on June 09, 2009, 01:08:17 pm ---because Africa is affected by malaria also and malaria's virus need oxygen to reproduce in body, so ppl with sickle cell anemia have less oxygen in the re blood cell thus virus cant reproduce and they survive from malaria,hence this remains in generation!!!
simple!
;) ;)
--- End quote ---
i rote tht only ppl who are heterozygous tend to survive hence the population tends to develop sickle shaped rbcs n only those who r heterozygous survives n according to natural selection only the organism which is welll adapted to its surroundings can survive so this one way of adaptation
am i correctin nyway plz temme ???
--- End quote ---
i think u r right!
--- End quote ---
wht did u write
hdbkiwi:
Here this is the definite correct thing on everything about malaria:
The mosquito is the vector for the pathogen Plasmodium. Plasmodium multiplies in the stomach wall of the mosquito, then migrates to the salivary glands.
Plasmodium is the protoctist that causes malaria. It can reproduce sexually inside the mosquito, and the resulting variation makes the production of vaccines VERY difficult.
so:
1.An infected mosquito passes on parasites to an uninfected human. Plasmodium passes down the piercing mouthparts from the mosquito's salivary glands.
2. Parasites multiply RAPIDLY in the human liver, and are then released into the blood.
3. Parasites then invade RBCs, where they feed on haemoglobin then multiply by multiple fission. then they burst, etc etc
So the people with Sickle cell must have the abnormal haemoglobin that the plasmodium can't eat or something :)
(I don't think you need THIS much detail in the exam :P lol) :D
girl_92:
--- Quote from: hdbkiwi on June 09, 2009, 01:18:22 pm ---Here this is the definite correct thing on everything about malaria:
The mosquito is the vector for the pathogen Plasmodium. Plasmodium multiplies in the stomach wall of the mosquito, then migrates to the salivary glands.
Plasmodium is the protoctist that causes malaria. It can reproduce sexually inside the mosquito, and the resulting variation makes the production of vaccines VERY difficult.
so:
1.An infected mosquito passes on parasites to an uninfected human. Plasmodium passes down the piercing mouthparts from the mosquito's salivary glands.
2. Parasites multiply RAPIDLY in the human liver, and are then released into the blood.
3. Parasites then invade RBCs, where they feed on haemoglobin then multiply by multiple fission. then they burst, etc etc
So the people with Sickle cell must have the abnormal haemoglobin that the plasmodium can't eat or something :)
(I don't think you need THIS much detail in the exam :P lol) :D
--- End quote ---
hey we dont need to noe so much i wanna noe wht exactly shuld be included in the answer
nywayz the info is gud
hdbkiwi:
So model answer:
Mosquito carrying malaria virus BITES people who have sickle cell aneamia, and those who don't (1 mark)
The people who don't have the sickle cell aneamia die (1), and those who do have it, don't as they are resistant (1)
So, the resistant people survive and breed, thus creating a higher population of resistant people (1)
:)
girl_92:
--- Quote from: hdbkiwi on June 09, 2009, 01:24:30 pm ---So model answer:
Mosquito carrying malaria virus BITES people who have sickle cell aneamia, and those who don't (1 mark)
The people who don't have the sickle cell aneamia die (1), and those who do have it, don't as they are resistant (1)
So, the resistant people survive and breed, thus creating a higher population of resistant people (1)
:)
--- End quote ---
thanx
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