Qualification > Sciences
ALL CIE BIOLOGY DOUBTS HERE !!!
Aadeez || Zafar:
--- Quote from: Amelia on May 18, 2011, 06:12:51 pm ---Sickle-cell anaemia provides protection against malaria. The parasite cannot survive in the blood cells of a person who has got the heterogenous sickle cell genes.
Individuals carrying just one copy of the sickle mutation (inherited from either the father or mother) were known not to develop sickle cell anemia, leading rather normal lives. However, it was found that these same individuals, said to carry the sickle cell trait, were in fact highly protected against malaria, thus explaining the high prevalence of this mutation in geographical areas where malaria is endemic.
--- End quote ---
malarial parasite cnt acctually enter the RBC which r not biconcav
it cn attack only healthy RBC
SICKLE CEELL ANEMIA cuses deformation of RBC and it is HEREDITRCAL desease cused by Genetic DISOORDER
Vampire-Love4ever:
Explain how crossing over leads to variation.
Master_Key:
--- Quote from: Vampire-Love4ever on May 24, 2011, 11:26:48 am ---Explain how crossing over leads to variation.
--- End quote ---
Crossing over changes some of the chromatids sequence. This results in different alleles expressed. So variation is seen.
Vampire-Love4ever:
--- Quote from: Master_Key on May 24, 2011, 02:18:09 pm ---Crossing over changes some of the chromatids sequence. This results in different alleles expressed. So variation is seen.
--- End quote ---
Thanks. :)
Vampire-Love4ever:
Role of plasmodesmata.
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