AS Edexcel Biology Unit 1 June 12- 14th of May

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Reply 140

ummm

Original post by bertiejess

do we need to know about apolipoproteins A B and E?

Nope, never heard of that in my life.

Reply 141

dineshn

Hey guys, you know the diagram on pg 89 of the orange textbook, and pg 38 of the pink revision guide - do we need to know it? i dont get it at all!!!

Reply 142

Kabelan1

Good Luck to Everyone, Hope you all do well. :smile:

Reply 143

Fisheh

Original post by dineshn

Hey guys, you know the diagram on pg 89 of the orange textbook, and pg 38 of the pink revision guide - do we need to know it? i dont get it at all!!!

if you mean mutation, no.

Reply 144

dineshn

Original post by Fisheh

if you mean mutation, no.

yh the CF mutation and ATP blah blah... thanks a lot, thats a relief

Reply 145

stonesoup95

Can anyone explain translation process in steps?
I understood transcription completely but have no idea what to write if question is asked and have 3-5 marks. I couldn't find any past paper which asked translation. What should I write if the question is asked?

Reply 146

Emilii

1. A ribosome attaches to the mRNA at an initiation codon. The ribosome encloses 2 codons. tRNA with specific amino acid attached diffuses to the ribosome and the anticodon on the tRNA attaches to the mRNA start codon by complementary base pairing.
2. The next tRNA and amino acid combination attaches to the adjacent mRNA codon.
3. The bond between the tRNA and amino acid is cut and a peptide bond is formed between the two Amino acids. The free tRNA molecule leaves to collect another amino acid.
4. The ribosome moves along one codon so that a new amino acid and tRNA combination can attach. The polypeptide chain elongates one amino acid a time, and peels away from the ribosome folding up into a protein as it goes. This continues until a stop codon is reached.

The main function of the ribosome is to hold the mRNA molecule so that antacodons of tRNA can pair with complementary codons of mRNA. This brings amino acids to lie adjacent to each other so that peptide bonds can be formed.

Reply 147

mrperfect

Original post by YellowAndBlack

Who took edexcel IGCSE biology last year?

I took it. Paper 1 was the worst paper I've ever seen. I should've got an A* but paper 1 messed up my resut. I ended up with an A.

Reply 148

dineshn

All nighterrrrrrrrrrrrrrrr

Reply 149

danger-.-

Original post by dineshn

Hey guys, you know the diagram on pg 89 of the orange textbook, and pg 38 of the pink revision guide - do we need to know it? i dont get it at all!!!

dude you do need to know bout the cftr mutation !!

Reply 150

danger-.-

guyz can you plz explain me the 3 experiments we need to know for today .. i lost the papers after unit 3 !!! help ! =/

Reply 151

dineshn

Original post by danger-.-

dude you do need to know bout the cftr mutation !!

Yh i know but i just dont understand that diagram

Reply 152

amber109

didnt sleep well at all last night...

Reply 153

amr9595

Original post by danger-.-

guyz can you plz explain me the 3 experiments we need to know for today .. i lost the papers after unit 3 !!! help ! =/

beetroot experiment for membrane permiability, effect of temperature and alcohol
yu know the steps right?the explanation is as yu increase temperature permiability increases as phospholipid molecules move faster and the perm increases, and if the temperature in the graph is above 40 degree and they ask yu to explain the significnt increase, answer tht this temp might melt down the phospholipid part and the protiens in the membrane deform inscreasing the perm significantly
alcohol dissolve the lipid part increasing permiability

daphnia experiment , effect of caffeine on its heart rate
and the vitamine C, dcpip experiment