BIOLOGY PAPER 22

[annarust]

About the differences between HbA and HbS, I wrote that HbS is recessive and HbA is dominant thus only a homozygous HbS pair would code for sickle cell anaemia... Is that wrong?

 

[annarust]

And what did you guys include in the drawing of the cell membrane? :/ wasn't sure about that one.

 

[annarust]

About the balance of prevention and cure: I answered COMPLETELY differently :/ I said that the bypass is not able to completely cure the blockage (since it does not remove it, only 'bypasses' it) but that it can prevent the spreading of the blockage (and prevent, for instance, cardiac arrest). Is that wrong?

 

[annarust]

HbS is not recessive, it is the allele which is recessive...

Aren't HbA and HbS alleles?

 

[Nishii]

i included that HbS, a base substition occurs whereby the new triplet codes for the amino acid valine(hydrophobic) instead of glutamic acid(hydrophilic) etc!

 

[Nishii]

And what did you guys include in the drawing of the cell membrane? :/ wasn't sure about that one.

i added glycolipids, glycoproteins, intrinsic proteins, carrier/channel proteins and the other structures asked! i forgot to label inner and outer surface.. its on 5 marks, any idea on how many marks i'll lose??

 

[xtremeforums]

Do you guys remember that graph question on ATP concentration?? What did u all write for that?
i wrote ara-ATP is a competitive inhibitor.... because increasing the concentration of ATP, has an effect on the rate of DNA synthesis...

 

[Nishii]

competitive?! i wrote non competitive because increasing substrate concentration does not increase the reaction rate!

 

[xtremeforums]

i added glycolipids, glycoproteins, intrinsic proteins, carrier/channel proteins and the other structures asked! i forgot to label inner and outer surface.. its on 5 marks, any idea on how many marks i'll lose??

U wouldnt loose more than a mark for that....

i only added channel proteins, cholestrol, and glycoproteins, along with the structures asked to be added... That was enough right?

 

[xtremeforums]

competitive?! i wrote non competitive because increasing substrate concentration does not increase the reaction rate!

But the rate of reaction WAS increasing wasn't it??

 

[Nishii]

yeah! i think there was one mark for each label and structure asked!

 

[Nishii]

But the rate of reaction WAS increasing wasn't it??

it was increasing as not all the inhibitors had bonded to all the enzymes. some active sites were free and still available for subtrate to bind! if it was competitive, the curves with ara atp would be approaching the curve without ara atp, right?!

 

[xtremeforums]

it was increasing as not all the inhibitors had bonded to the enzymes. if it was competitive, the curves with ara atp would be approaching the curve without ara atp, right?!

yah i thought of that in the exam... i guess ur right!
BUT MAYYBBEEE increasing the concentration of ATP more, would cause it to reach the same curve? because the curves ddnt become horizontal, they were still rising...?

 

[Nishii]

no they were already reaching a plateau.. nevermind, you will probably lose only one mark if you have described the graph correctly! you just got the "explain" part wrong!

 

[xtremeforums]

no they were already reaching a plateau.. nevermind, you will probably lose only one mark if you have described the graph correctly! you just got the "explain" part wrong!

i hope so!

 

[annarust]

i added glycolipids, glycoproteins, intrinsic proteins, carrier/channel proteins and the other structures asked! i forgot to label inner and outer surface.. its on 5 marks, any idea on how many marks i'll lose??

Probably just the one, don't worry

 

[NouranAyman]

firstly for the magnification i got 1600 ;D and for the water question i wrote about ph is suitable and temperature for the activity of enzymes and i dont remember wat else density i guess blabla xD and for DNA stable question i wrote about its structure and the phosphodiester bonds xD nd hydrogen bonds as well.....the last question about the bypass surgeery i dint get wat to write i guess that one was wrong.... the paper was okay i guess curve will be 45/60 and i hope its lower!! Good luck to all isA

 

[Nishii]

hey for the first question, (structures seen in electron micrograph) i said RER, cristae of mitochondria and thylakoids of chloroplasts! d'you think its right?

 

[NouranAyman]

hey for the first question, (structures seen in electron micrograph) i said RER, cristae of mitochondria and thylakoids of chloroplasts! d'you think its right?

yes its right as long as it wasnt seen in the picture (Y)

 

[NouranAyman]

what did u write for the question about water, and the one about the graph , the enzyme one Atp and ara ATP