ALL CIE BIOLOGY DOUBTS HERE !!!

[HUSH1994]

yeah its AS why else would i post it here?

[Most UniQue™]

yeah its AS why else would i post it here?

oh so i cnt help sry

[Master_Key]

yeah its AS why else would i post it here?

Hey hush!

It involves the hydration of C-N that's amide bond.

One product is a -COOH.

Another is an -NH₂.

Note:- C-N bond is broken so separate the molecule from here. R-COOH  AND H₂N-R.

[Amelia]

Thanks alot Amelia +rep ,sorry for the trouble but can you explain the second question again ;(

The mRNA forms the polypeptide chain and the tRNA molecules bring forth the anti-codons required to make the polypeptide chain.

The tRNA A is CAU - it's complementry codon in mRNA will be GUA (aminoacid Valine is present in the formation of sickle cell)
The tRNA B is CUU - it's complementry codon in mRNA will be GAA (aminoacid glutamine is present in the formation of sickle cell)
The tRNA C is UGA - complementry codon in mRNA is ACU (thronine is also present in the formation of amino acid of sickle cell)
But the tRNA D is UGC and its codon in mRNA is ACG (therefore, this amino acid is 'not' present in the formation of sickle cell)

[HUSH1994]

Thanks alot Amelia & Master for your explanation

[Amelia]

Thanks alot Amelia & Master for your explanation

Keep posting. 

Good Luck, mate.

[Master_Key]

Thanks alot Amelia & Master for your explanation

ANYTIME dude.

[$H00t!N& $t@r]

hey
need help with Q 24 and 30 M/J 2006 P1

[Aadeez || Zafar]

hey
need help with Q 24 and 30 M/J 2006 P1

Q24

u have 20% of cytocine in DNA so this will be transcripted to 20% guanine in mRNA
U have 20 % of cytocine in DNA so there would be 20 % guanine (its complimantory base pair) which will be transcripted to guanine (20% in mRNA)

u r left with :- 100-(20+20) = 60%

this 60% would includes both Ucracil and ADenine bot in equal proprtion  as they are complimentory base pai
so half of 60 % would be ucracil

60%/2 = 30%

Q30

i know that co2 concentration would shift X to Y but dont know how cn this be dne by increasing pH

[$H00t!N& $t@r]

Q24

u have 20% of cytocine in DNA so this will be transcripted to 20% guanine in mRNA
U have 20 % of cytocine in DNA so there would be 20 % guanine (its complimantory base pair) which will be transcripted to guanine (20% in mRNA)

u r left with :- 100-(20+20) = 60%

this 60% would includes both Ucracil and ADenine bot in equal proprtion  as they are complimentory base pai
so half of 60 % would be ucracil

60%/2 = 30%

Q30

i know that co2 concentration would shift X to Y but dont know how cn this be dne by increasing pH

Thanks for the answer. I understand the first one but for Q30 I think you answered a wrong question. I'm talking about the one with the atrio-ventricular and the semi-lunar valves..

[$H00t!N& $t@r]

can someone please draw an outline of how you would draw a table for question 1b(i) m/j 2007 31 without the values...just the column headings.

Here is the link: http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9700%20-%20Biology/9700_s07_qp_31.pdf

[Master_Key]

can someone please draw an outline of how you would draw a table for question 1b(i) m/j 2007 31 without the values...just the column headings.

Here is the link: http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9700%20-%20Biology/9700_s07_qp_31.pdf

place 2 cm3 of distilled water in a test-tube.
• add 2 cm3 of starch solution.
• add 0.5 cm3 of amylase and start timing.
• after five minutes add four drops of iodine solution and shake gently.

So we got

Note:- Keep the time for the experiment constant as for example 5 minutes for Amylase to work on Starch.

VOLUME OF STARCH ADDED
VOLUME OF AMYLASE ADDED
CONCENTRATION OF LEAD NITRATE ADDED
TIME TAKEN FOR STARCH TEST TO OBTAIN RESULT / TIME TAKEN FOR BLUE-BLACK COLOUR TO DEVELOP

[$H00t!N& $t@r]

Is the concentration of lead nitrate meant to be in %  ?

Is it going to be something like this:  volume of lead nitrate
                                                 ----------------------       x 100
                                         volume of (lead nitrate + water)

[Master_Key]

Is the concentration of lead nitrate meant to be in %  ?

Is it going to be something like this:  volume of lead nitrate
                                                 ----------------------       x 100
                                         volume of (lead nitrate + water)

If the question has it in % then take it in %.

For eg. 1% CuSo₄ is 1% of mass of solution not necessarily volume.

[Vampire-Love4ever]

Method of measuring curvature?

Specimen Paper 5-2007, Q2: mentioned in the marking scheme.