A level Biology: Post your doubts here!

[XPFMember]

Re: Stuck in Biology?? Post your doubts here!!

Assalamoalaikum!!

Can somebody tell me how do I write the answer to this question:

Explain the role of NADP in photosynthesis. [6]

Mark Scheme points are as follows:

15 coenzyme ;
16 reduced ;
17 carries protons ;
18 and (high energy) electrons ;
19 from photosystem7light stage ; R photosystem II
20 on thylakoid membrane grans ;
21 to stroma / Calvin cycl~
22 ref. regeneration of NADP ;

9700/M/J/04/ Q:7(b)

Jazakumullah Khairen!

 

[rz123]

Re: Stuck in Biology?? Post your doubts here!!

can someone explain me clearly with an example how to find the probability of null hypothesis being correct form the probability table and what are these degrees of freedom. thanks a lot.

 

[rz123]

Re: Stuck in Biology?? Post your doubts here!!

^^ You just need to elaborate these points.
The co-enzyme NADP is used to add hydrogen in CO2 to produces carbohydrate molecule such as glucose. in the light dependent stage,after the photophosphorylation, and at the end of the electron carrier chain, the electron is picked up by PS1 to replace the electron the chlorophyll in PSI had lost in the initial stages. Now these electrons are again passed from PSI to a different chain of carriers to NADP. The NADP also picks up the hydrogen ions from the split water molecules. The NADP becomes reduced now which will be used further in the light independent stage to convert the glycerate 3 phosphate into triose phoshphate which is the 1st carbohydrate to be produced in the photosynthesis.

 

[princesszahra]

Re: Stuck in Biology?? Post your doubts here!!

Assalamoalaikum!!

Can somebody tell me how do I write the answer to this question:

Explain the role of NADP in photosynthesis. [6]

Mark Scheme points are as follows:

15 coenzyme ;
16 reduced ;
17 carries protons ;
18 and (high energy) electrons ;
19 from photosystem7light stage ; R photosystem II
20 on thylakoid membrane grans ;
21 to stroma / Calvin cycl~
22 ref. regeneration of NADP ;

9700/M/J/04/ Q:7(b)

Jazakumullah Khairen!

just explain them in a line !!

 

[memyself15]

Re: Stuck in Biology?? Post your doubts here!!

NADP is a co-enzyme that serves as an electron acceptor in the electron transport system during photophosphorylation. The electrons released from the 'excited' chlorophyll in PS1 combine with an electron acceptor and pass down a chain that ends with NADP. During photolysis of water, the protons from the splitting of the water molecule help to form reduced NADP along with the electrons from PS1 that combined with the NADP. The reduced NADP then passes along the electrons on to the calvin cycle. During this cycle, glycerate phosphate is reduced to another 3C sugar called triose phosphate, which is phosphoglyceraldehyde by using the reduced NADP from the light dependent stage as the electron donor and ATP is required. NADP then returns to the light dependent stage to pick up another hydrogen ion.

HOPE THAT HELPS...!

 

[hassam]

Re: Stuck in Biology?? Post your doubts here!!

NOTE BROTHER....u shud say nadp+ as HYDROGEN ACCEPTOR ON A CIE EXAM !!! ....their ms say so

 

[hassam]

Re: Stuck in Biology?? Post your doubts here!!

 

[hassam]

Re: Stuck in Biology?? Post your doubts here!!


Outline how this apparatus is used to measure the rate of oxygen uptake by a known
mass of germinating seeds.
i know the working mechanism...bt cn somebody tell me some important experimental details abt this

 

[Newbie]

Re: Stuck in Biology?? Post your doubts here!!

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Notes, animations, tutorials and questions with instant feedback. This is the student support web site for the American textbook: Life, The Science of Biology.

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Kimball's Biology Pages: an American on-line textbook. Very well organised so that you can find information easily.

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DNA from the beginning: on-line tutorials on the structure of DNA , genetics and genetic organisation and control. 41 different topics in all.

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An excellent site that shows you what happens during the cardiac cycle.

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Click on The Biology Place and find tutorials, animations and tests on a variety of topics including common A level Biology practicals.

 

[Bouchra]

Re: Stuck in Biology?? Post your doubts here!!

I'm self-studying for my IGCSE biology paper, and I have my Alt to Practical in a couple of weeks. How do I prepare for this paper even though I do not have access to any kind of laboratory?

Thanks

 

[OakMoon!]

@Bouchra: This is the A'levels section, post your doubts in the IGCSE section. Thankyou!

Anyways, Alternate to Practical is more of knowing about techniques rather than performing them. You just need the theory and not the practical skills. Just practice past papers and look into marking schemes, plus apply Biological and general knowledge to successfully prepare for the ATP.

 

[Bouchra]

@Bouchra: This is the A'levels section, post your doubts in the IGCSE section. Thankyou!

Anyways, Alternate to Practical is more of knowing about techniques rather than performing them. You just need the theory and not the practical skills. Just practice past papers and look into marking schemes, plus apply Biological and general knowledge to successfully prepare for the ATP.

I'm sorry, but I didn't realize that till I had finished posting. Thanks for the answer.

 

[Safia05]

http://users.rcn.com/jkimball.ma.ultran ... Stahl.html
Could someone help me to have a simplified explanation on this experiment?
how did the nitrogen-15 affect this experiment ?
& what are the reasonings behind the different densities of the test tubes?
*Suggest a site please*

:%) :%) :%) :%)

 

[rz123]

http://www.youtube.com/watch?v=mfnDVV518es

this will make it easier and simpler. check it out.

 

[makaveli]

Biology 9700 paper 3 and paper 5

Guys please help me ...
Im a privet student taking biology A-level....
so I have no school in order to practice biology paper 3 and paper 5
can you please help me ????
How should I study these papers ???
Are there any websites I should visite ???
Thank you so much ....

 

[OakMoon!]

There are academies that help you with the practical paper. Try to find one such academy because performance of the practicals is vital to do well in the paper 3. While, for paper 5 just read the marking schemes and the experiments in the book.

 

[hassam]

Describe the structure of a myelinated sensory neurone.
in questions like this on section B ....are we allowed to explain the structure with annotations a large labelled diagram??

 

[XPFMember]

Describe the structure of a myelinated sensory neurone.
in questions like this on section B ....are we allowed to explain the structure with annotations a large labelled diagram??

Assalamoalaikum!!

Yeah, you are! Actually for such questions, it is better to draw a diagram and label everything, make sure if the question is for 7 marks you've at least 7 things labelled. Better if you have more than that though! I read in the examiner report that, when it was just enough for the candidates to draw a labelled diagram, they went on to describe..so u see it's a good and an easy option to draw a labelled diagram!

Similar is the case for describing the structure of a kidney nephron!


Anyways, I need help with Q:7 (iii) of this paper: http://www.xtremepapers.com/CIE/Interna ... 8_qp_4.pdf

Please help..i dont understand why is the water conc. more in the collecting duct when it's reabsorbed??!! :%)

Please if somebody cud tell me what exactly do i have to wite in the answer?!
JazakAllah Khair!

 

[princesszahra]

Describe the structure of a myelinated sensory neurone.
in questions like this on section B ....are we allowed to explain the structure with annotations a large labelled diagram??

Assalamoalaikum!!

Yeah, you are! Actually for such questions, it is better to draw a diagram and label everything, make sure if the question is for 7 marks you've at least 7 things labelled. Better if you have more than that though! I read in the examiner report that, when it was just enough for the candidates to draw a labelled diagram, they went on to describe..so u see it's a good and an easy option to draw a labelled diagram!

Similar is the case for describing the structure of a kidney nephron!


Anyways, I need help with Q:7 (iii) of this paper: http://www.xtremepapers.com/CIE/Interna ... 8_qp_4.pdf

Please help..i dont understand why is the water conc. more in the collecting duct when it's reabsorbed??!! :%)

Please if somebody cud tell me what exactly do i have to wite in the answer?!
JazakAllah Khair!

Q7 iii
u have to explain the reasons of different concentrations !
so u say that all the urea from the blood has been filtered out due.( explain the reason of this filteration in one line), none of the urea is reabsorbed .
the conc of urea in urine is 2 ( units) because all the urea has been moved into the loop of henle(explain this process in one line).

hope u get it!!

 

[XPFMember]

waitt...i'm still confused...