A level Biology: Post your doubts here!

[PhyZac]

There is a question in the pastpapers that says an enzyme will hydrolyze the hinge region of antibodies and break the antibodies into "3" fragments. How can they break into 3????? Shouldn't the antibodies break into 2 parts each contains one heavy chain and one light chain if hydrolysis occurs at the hinge region??

I deleted my other post, because i think i did it wrong. Look at the reaction from the one top to the one below....this is the fragmentation occurring.

 

[PhyZac]

hi....im attachin notes for A2 energy and Respiration......msg me if u need notes on other chapters...........hope youll find them helpful.

Chapter, evolution please.

P.S. good notes, JazakaAllah khairan.

 

[lyuchenqujoy]

I deleted my other post, because i think i did it wrong. Look at the reaction from the one top to the one below....this is the fragmentation occurring.

thank you!!
when I saw the question I thought it meant break the disulfide bonds in the hinge region ORZ...So the hydrolysis is occurring at the polypeptide chains but not at the bonds, right?

 

[PhyZac]

thank you!!
when I saw the question I thought it meant break the disulfide bonds in the hinge region ORZ...So the hydrolysis is occurring at the polypeptide chains but not at the bonds, right?

Well see, the thing is we study a very simplified way of antibody, a little more accurate is image below, notice where is hinge region, doesnt seem to be a polypeptide, but i dont know what is hinge region made of actually.

 

[lyuchenqujoy]

Well see, the thing is we study a very simplified way of antibody, a little more accurate is image below, notice where is hinge region, doesnt seem to be a polypeptide, but i dont know what is hinge region made of actually.

thank you anyway >w<

 

[Malik777]

 

[lyuchenqujoy]

View attachment 22701View attachment 22701

well, I think the answer is C and A, am I correct?

 

[Amy Bloom]

Well see, the thing is we study a very simplified way of antibody, a little more accurate is image below, notice where is hinge region, doesnt seem to be a polypeptide, but i dont know what is hinge region made of actually.

From the picture here i guess the hinge region is made up of polypeptide coz you can see the disulfide bridges here. this is what i think.

 

[Amy Bloom]

I deleted my other post, because i think i did it wrong. Look at the reaction from the one top to the one below....this is the fragmentation occurring.

So we can say that the fragmentation process depends on which hydrolytic enzyme the antibody is exposed to right?

 

[lyuchenqujoy]

In my view its B and B

well, here's my opinion..
since the eukaryotic cells do not have nucleus so mitosis cannot occur..
and the second question..I've seen that question before but I forgot from which paper it is in.. RER has ribosomes so mRNA can also be found there

 

[Amy Bloom]

well, here's my opinion..
since the eukaryotic cells do not have nucleus so mitosis cannot occur..
and the second question..I've seen that question before but I forgot from which paper it is in.. RER has ribosomes so mRNA can also be found there

Eukaryotic cells have nucleus, not prokaryotes, careful. (1st quest)
Yeah true i forgot that *facepalm* you're right. (2nd quest)
i'll delete my post for no confusion.
Yeah so the answer is C and A

 

[lyuchenqujoy]

Eukaryotic cells have nucleus, not prokaryotes, careful. (1st quest)
Yeah true i forgot that *facepalm* you're right. (2nd quest)
i'll delete my post for no confusion.
Yeah so the answer is C and A

for god's sake I always mix up those 2 words .... I swear the thing in my mind is prokaryote... Thanks for pointing out this stupid mistake...

 

[Amy Bloom]

for god's sake I always mix up those 2 words .... I swear the thing in my mind is prokaryote... Thanks for pointing out this stupid mistake...

I understand. it happened to me several times, esp in maths. its okay, u're welcum sis.

 

[Ahmad Zaeem]

Oct/ Nov P 53 Q 2 (b)(2) .......How to find the expected (E) values here ????......I found the first one by ..... ( 21+32+19+40) /4
giving me 28 as (E) for with tails ....but i don't know Why ....so concept plsss.....and also 2nd one ....???...

(*_-)..........
http://papers.xtremepapers.com/CIE/...nd AS Level/Biology (9700)/9700_w11_qp_53.pdf

 

[Malik777]

well, here's my opinion..
since the eukaryotic cells do not have nucleus so mitosis cannot occur..
and the second question..I've seen that question before but I forgot from which paper it is in.. RER has ribosomes so mRNA can also be found there

Its C & A

 

[NouranAyman]

Guys I need HELP!! Im taking Biology A level in june! Now any tips how to learn all this? plus about the pastpapers! specially paper 4 has a lot to learnnnn!! Guys help tell me what should I do?

 

[Mary_Jones]

Could anyone please help me with question 1b? http://papers.xtremepapers.com/CIE/...and AS Level/Biology (9700)/9700_s06_qp_5.pdf
thank youu

 

[Amy Bloom]

Could anyone please help me with question 1b? http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s06_qp_5.pdf
thank youu

Here u are.
If there is any mistake in explanations please correct me.

 

[Amy Bloom]

Guys I need HELP!! Im taking Biology A level in june! Now any tips how to learn all this? plus about the pastpapers! specially paper 4 has a lot to learnnnn!! Guys help tell me what should I do?

This is what i did 1 month prior to my Nov exams. I never revised in order in the syllabus, i revised chapters with are bulky first and those which i had difficulties. Now it depends on you. If you are giving the A2 paper 4 exam first, tackle A2 first because there are so many things. I went in this order:
Start revising Regulation and control (Kidney, Nervous, endocrine), Inherited change, Selection & evolution, Respiration and Photosynthesis. [A2 core]
Then go to Applications: Gene Tech, Biotech, Crop plants, Reproduction and biodiversity [ Applications ]
Revise like 2 topics of A2 and 1 Application per day. depends on your schedule now.
You r now ready for paper 4 (2007-2012.). . Run this in parallel with the following:
Tackle AS now
Transport (Animals +Plants), Infectious disease, Immunity, Ecology, Gas exchange, Gen. control, enzymes, biochemistry, cell structure, Cell membrane and transport, Cell and nuclear division. It depends on you which you find bulky and difficult. Finish all of these in no more than 3 days.
Once this is finished, tackle papers 1 and 2
Revise paper 3 (practicals, review them). and tackle paper 5.

This is what i basically did, but, still it depends on you how much time you spend to study and what r u priority chapters.
Hope i helped and good luck

 

[xyz!]

Hey guys...pls help me out wid dis multiple choice questn..
Q. Which of the following is translated completely?
i) AUGUGAUUAAAGAA
ii) AUGAUAUUGCCCUGA
iii) AGUUCCAGACUCUAA
iv) AUGUACAGUAACUAG
The answer given is. (ii) bt how?