IGCSE Biology Paper 3

[Devina]

forda calculations i got 19% and x2000
wat did yu guys get??

i think it was 200...
anybody??...12/0.06...

yea dude i did the same but it was 0.06mm

i got 2000   what about 19 % where was dat  remind me maddy darling !!!!!

aunty it was tht energy wheat wala question

devi whr  r u

redbull's always HERE   !!!!!!!

yea n even redbulls fans

By the way who the hell r u

whts the name of the red bull fan

i thnk devi he ranaway he got scared

lolwa    kaun hai jo mujhse scared nhi hotaa ??  RED = Danger

[girl_92]

yea n abt tht sickle cell anaemia que wht did u guyz write abt why does it occur in africa
plz reply

[girl_92]

forda calculations i got 19% and x2000
wat did yu guys get??

i think it was 200...
anybody??...12/0.06...

yea dude i did the same but it was 0.06mm

i got 2000   what about 19 % where was dat  remind me maddy darling !!!!!

aunty it was tht energy wheat wala question

devi whr  r u

redbull's always HERE   !!!!!!!

yea n even redbulls fans

By the way who the hell r u

whts the name of the red bull fan

i thnk devi he ranaway he got scared

lolwa    kaun hai jo mujhse scared nhi hotaa ??  RED = Danger

hehe
chal hai this is student forum yaha pe nahi yaha pe onli exams ki baat

[°o.O-hash94-O.o°]

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!

 

[hdbkiwi]

Please stick to english so everyone can understand
It was a nutural selection question madee

[girl_92]

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!

 

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

[hdbkiwi]

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!

 

Umm plasmodium doesn't need oxygen to undergo sexual reproduction I thought?
What (I hope its right ) happens is that a mosquito carrying the plasmodium pathogen (that causes malaria) bites someone with sickle cell aneamia, and a normal person-the normal person gets malaria and dies-the sickle cell person does not, as they have resistance to it(I don't think you need to write why they have the resistance) Thus, more 'normal' people die, sickle people survive, so natural selection has occured and the sickle people breed and then produce more sickle people, so pop of them increases

[girl_92]

Please stick to english so everyone can understand
It was a nutural selection question madee

yup

[°o.O-hash94-O.o°]

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!

 

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

i think u r right!

[hdbkiwi]

Please stick to english so everyone can understand
It was a nutural selection question madee

yup

thanks hehe

[girl_92]

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!

 

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

i think u r right!

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 lol)

[girl_92]

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 lol)

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]

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)

thanx