Author Topic: IGCSE Biology Paper 3  (Read 23532 times)

Offline Devina

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Re: IGCSE Biology Paper 3
« Reply #150 on: June 09, 2009, 01:04:46 pm »
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

Offline girl_92

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Re: IGCSE Biology Paper 3
« Reply #151 on: June 09, 2009, 01:05:14 pm »
yea n abt tht sickle cell anaemia que wht did u guyz write abt why does it occur in africa
plz reply
some people sleep to dream while othrs wakeup to follow dem im the second type how abt u

Offline girl_92

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Re: IGCSE Biology Paper 3
« Reply #152 on: June 09, 2009, 01:06:22 pm »
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 :)
some people sleep to dream while othrs wakeup to follow dem im the second type how abt u

Offline °o.O-hash94-O.o°

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Re: IGCSE Biology Paper 3
« Reply #153 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!

 ;) ;)

Offline hdbkiwi

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Re: IGCSE Biology Paper 3
« Reply #154 on: June 09, 2009, 01:10:23 pm »
Please stick to english so everyone can understand :)
It was a nutural selection question madee
Excuse me... have you seen my sanity... I think I lost it. ;)

Offline girl_92

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Re: IGCSE Biology Paper 3
« Reply #155 on: June 09, 2009, 01:12:54 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!

 ;) ;)

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 ???
some people sleep to dream while othrs wakeup to follow dem im the second type how abt u

Offline hdbkiwi

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Re: IGCSE Biology Paper 3
« Reply #156 on: June 09, 2009, 01:13:05 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!

 ;) ;)
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 :)
Excuse me... have you seen my sanity... I think I lost it. ;)

Offline girl_92

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Re: IGCSE Biology Paper 3
« Reply #157 on: June 09, 2009, 01:13:34 pm »
Please stick to english so everyone can understand :)
It was a nutural selection question madee
yup
some people sleep to dream while othrs wakeup to follow dem im the second type how abt u

Offline °o.O-hash94-O.o°

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Re: IGCSE Biology Paper 3
« Reply #158 on: June 09, 2009, 01:14:25 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!

 ;) ;)

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!

Offline hdbkiwi

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Re: IGCSE Biology Paper 3
« Reply #159 on: June 09, 2009, 01:14:30 pm »
Please stick to english so everyone can understand :)
It was a nutural selection question madee
yup
thanks hehe
Excuse me... have you seen my sanity... I think I lost it. ;)

Offline girl_92

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Re: IGCSE Biology Paper 3
« Reply #160 on: June 09, 2009, 01:15:59 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!

 ;) ;)

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
some people sleep to dream while othrs wakeup to follow dem im the second type how abt u

Offline hdbkiwi

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Re: IGCSE Biology Paper 3
« Reply #161 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
Excuse me... have you seen my sanity... I think I lost it. ;)

Offline girl_92

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Re: IGCSE Biology Paper 3
« Reply #162 on: June 09, 2009, 01:21:55 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

hey we dont need to noe so much i wanna noe wht exactly shuld be included in the answer
nywayz the info is gud
some people sleep to dream while othrs wakeup to follow dem im the second type how abt u

Offline hdbkiwi

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Re: IGCSE Biology Paper 3
« Reply #163 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)

:)
Excuse me... have you seen my sanity... I think I lost it. ;)

Offline girl_92

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Re: IGCSE Biology Paper 3
« Reply #164 on: June 09, 2009, 01:27:06 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)

:)
thanx
some people sleep to dream while othrs wakeup to follow dem im the second type how abt u