OCR Biology F212 (Molecules, Biodiversity, Food and Health)- 21st May 2012

1)DNA double helix between strands
2) cellulose between OH groups
3) between binding of substrate and active site of enzyme
4) tertiary strucuture of protein

help me

To test for the effect of pH on trypsin/ pepsin, use a range of pH buffers keeping other variables constant, and use a colorimeter to read how quickly the milk clears. Obviously low pH's will cause the milk to stay slightly more cloudy longer - in terms of trypsin- as the enzymes optimum pH is higher, so the majority of light should be absorbed.

I think

well done!!!
don't worry revise well and you will obviously get an A
to be honest I am not nervous. I am just waiting to see the paper

between the nitrogenous base eg adenine and guanine, in the secondary and tertiary structure of pollypeptides, also found between cellulose.

ya this book is not that good on this topic my teacher gave us all this info book has not even mentioned a thing
ok the steps are
-macrophage engulfs pathogen but keeps antigen
-take the antigen and present on its surface
-so T helper cells that have complementary shape to that of antigen gets activated. this is colonial selection
-now its here where you have to decide which part you need to answer
-if it activated T-killer cells then its cell mediated response
-if activates Plasma cells then its humoral respone

for cell mediated response
-T- helper cell release interleukin which stimulates T killer cell
-T-killer cell divides. this is colonial expansion.
-T-killer cell now destroys host cell
-also T memory cell forms this is also colonial expansion
-but memory cell remains in body
it does not take part in primary response

humoral response
-T-helper cells release interleukin and stimulate B cells to divide into plasma cells and memory cell. this is colonial expansion
-plasma cell release antibodies and destroy pathogen by agglutination and neutralization
- memory cells as alwaz remain in system and do no take part in primary response.
hope this helped

Ok. List 4 examples where Hydrogen Bonds are formed/found in biological molecules?

Yup! There's quite a few Your turn!

secondary and tertiary structure of protein
cellulose
DNA
water.

I know you're not! I can tell! You know EVERYTHING already. You don't have anything to worry about!

Can someone help me on this?
DNA replication:
-DNA helicase unwinds and unzips DNA (breaks hydrogen bonds)
-DNA polymerase attaches complimentary DNA nucleotides to exposed bases on DNA template.
-Phosphodiester bonds form between nucleotides making the sugar-phosphate backbone.
-Semi conservative replications - one original and one new strand in each of 2 new DNA molecules.
-ATP needed.

Protein Synthesis:
Transcription:
-Gene is read to make mRNA.
-Gene is unwound and unzipped by RNA helicase.
-Free RNA nucleotised added to exposed bases on one strand only (by RNA polymerase?)
-Phosphodiester bonds form between nucleotides to form mRNA molecule.

Translation:
-mRNA read by ribosome.
-Ribosome allows particular tRNA to come in.
-Bases on tRNA attach to mRNA by complimentary base pairing.
-Polypeptide chain forms on the outside of the ribosome.
(Is there any polymerase/helicase here?)

Please edit appropriately!

Ya but i think for b lymphocytes is different , as there are stimulated by the t helper cells but also arent they also complenmentory to the antigens so dont they also clonal select before being stimulated to differentiate by the t helper cells

can you ask me

Ok. Here's a question that requires detail.
State and explain the structure of Haemoglobin. Include Secondary, Tertiary and Quaternary Structure.

Explain the term biological catalyst(2)

Explain the term biological catalyst(2)

just finish your text book and past paper then there is nothing to worry about. and don't forget the key points. dats it!! if you start worrying about it then its gonna make it more worse so just stay calm.

how smoking causes lung cancer(4)