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biology paper 1 doubts

I

Irfan1995

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yazan1995 said:
i hope cholestrol is correct
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Cholesterol is definitely correct.
ijjukittu said:
How many of u are 100% sure about the question which says ' which bonds were effected on the beta-chain of the heamogloin'??? I did primary,secondary & tertiary bonds! & i have a strong logic behind that!!!!.....But few ppl are saying for 'primary only'.......
Which one You guys wrote????
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I'm 100% that tertiary is affected.
Just like the sickle-cell example given above, an polar amino acid is replaced by a non-polar one (primary structure changed). This also means that hydrogen bonds cannot be formed with the new amino acid (since it is non-polar, it can't have any N-H, O-H, or F-H groups) (secondary structure changed). Non-polar amino acids point towards the centre of a polypeptide and polar amino acids point on the outside, so now the globular structure is completely changed as the polypeptide has to roll up in a different way (tertiary structure changed).
The question was asking about the beta polypeptide only. So the beta polypeptide is not affected by a quaternary structure since that deals with how a polypeptide is linked to other polypeptides. In reality, the quaternary structure of haemoglobin did change, but that wasn't what they asked for in this question. They only wanted to know what levels of structure changed the single polypeptide chain only.
 
I

ijjukittu

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Irfan1995 said:
Cholesterol is definitely correct.

I'm 100% that tertiary is affected.
Just like the sickle-cell example given above, an polar amino acid is replaced by a non-polar one (primary structure changed). This also means that hydrogen bonds cannot be formed with the new amino acid (since it is non-polar, it can't have any N-H, O-H, or F-H groups) (secondary structure changed). Non-polar amino acids point towards the centre of a polypeptide and polar amino acids point on the outside, so now the globular structure is completely changed as the polypeptide has to roll up in a different way (tertiary structure changed).
The question was asking about the beta polypeptide only. So the beta polypeptide is not affected by a quaternary structure since that deals with how a polypeptide is linked to other polypeptides. In reality, the quaternary structure of haemoglobin did change, but that wasn't what they asked for in this question. They only wanted to know what levels of structure changed the single polypeptide chain only.
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Exactky! thats what i explained above! Briefly!!!......m also more than 80% sure about this answer :) Thanks for further confirmation :)
 
L

L-Girl

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what is the answer for the question that asked what would increase the fluidity when it increases?
 
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yazan1995

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why is sucrose rather than glucose is transported by phloem?
what did you guys answer for this question?
 
xtremeforums

xtremeforums

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Omar Hosny said:
It's glycolipids
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ZohaibAsad said:
there's a difference between a glycolipid and a phospho lipid. The cholestrol guy got it right.
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Yup, its suppose to be glycolipids.
The only structural difference between glycolipids and phospholipids is the head. In phospholipids, the head is a phosphate group; while in glycolipids, the head is a glucose mol. The tails are lipids in both. The tails could be unsaturated lipid chains, increasing kinks, and thereforre making the membrane more fluid.
Whereas, the cholestrol, just "maintains" the rigidity. Increasing cholestrol, doesnt necessarily mean that the fluidity would increase.

Phospholipids wasnt one of the options, so glycolipid has to be correct.
 
N

niya15

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hey which organelle can be seen in light microscope by using 400x ??
cristae of mitochondira?lysosomes?nuclei or grana of chloroplast/
 
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