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RESIT Edexcel Biology Unit 1 - 26th May (6BI01)

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What points did everyone make for the pedigree diagram where you had to prove that the allele was dominant?

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Reply 61
Original post by splog23
That's really strange, did you do it for raw cabbage when boiled from cold water? That's what the question asked for

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I only looked up raw cabbage on the table i think it had a value of 32.4 or something ahh so annoyed god if only I had like 5 extra min.
Reply 62
Original post by Excuse Me!
What points did everyone make for the pedigree diagram where you had to prove that the allele was dominant?

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That one was a nightmare, I put down everything I could about parent one being heterozygous and his kids having kids who were not affected and stuff. I basically rambled on with loads of useless info in the hope I could find a mark somewhere.

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Original post by splog23
That one was a nightmare, I put down everything I could about parent one being heterozygous and his kids having kids who were not affected and stuff. I basically rambled on with loads of useless info in the hope I could find a mark somewhere.

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Same with me. At least you have some examples. I just barely wrote definitions. Dominant is always expressed in phenotype. Unaffected must be recessive
Reply 64
what does everyone think the mark for A will be? 60-64 ?
Reply 65
Original post by kosmooos
Same with me. At least you have some examples. I just barely wrote definitions. Dominant is always expressed in phenotype. Unaffected must be recessive


I got confused because if one of them was Mm and the other was mm they still could have kids who were unaffected, so even if it was recessive, the same scenario would arise.

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Which were the QWC questions?
Reply 67
Original post by chemica
what does everyone think the mark for A will be? 60-64 ?


66 I suspect.

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Reply 68
Original post by splog23


christ, I do think it will be pretty high. bye bye A
Original post by chemica
what does everyone think the mark for A will be? 60-64 ?


Original post by splog23


The highest its been for an A in any Unit 1 exam was 63 in January 2013 so hopefully it won't be too high haha
Original post by Darcy-Darling
Which were the QWC questions?


The question about gaseous exchange in mammals was and I think possibly the last question on haemoglobin.
Reply 71
Original post by kdizzle97
The highest its been for an A in any Unit 1 exam was 63 in January 2013 so hopefully it won't be too high haha


Unfortunately because this paper was a mash-up of past paper questions that have been slightly altered, alongside us retaking it, the grade boundaries are likely to be higher.

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Reply 72
Original post by splog23
Unfortunately because this paper was a mash-up of past paper questions that have been slightly altered, alongside us retaking it, the grade boundaries are likely to be higher.

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I know what you mean.
Original post by splog23
Unfortunately because this paper was a mash-up of past paper questions that have been slightly altered, alongside us retaking it, the grade boundaries are likely to be higher.

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Can you check the mark scheme I posted?
Reply 74
Original post by melanin101
I had no idea that vitamin C had ester bonds :frown: I just wrote that bonds broke due to high temp lol


I wrote at high temperature channel proteins denature diffusion rate is faster more diffuses out of cells. What did you get for the one after about why there was more vitamin c lost when put into cold water and then boiling ?
Reply 75
Original post by kosmooos
Can you check the mark scheme I posted?


Where is this mark scheme?

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Original post by kdizzle97
I think I got 74.5%
Probably did it wrong though


I got the same as you haha
Unofficial markscheme please.. Thank you.
Original post by splog23
Where is this mark scheme?

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1) DNA protein synthesis, differences in DNA and RNA
Number of amino acids: 8
Number of tRNA: 6
Differences DNA contain deoxyribose
RNA contains ribose
DNA contains base thymine, RNA uracil
Third mark ( probably lost) DNA is double helix, mRNA is one strand and tRNA is part double stranded. DNA only in nucleus. RNA is in nucleus (mRNA) and cytoplasm (mRNA and tRNA)

2) vitamin c cabbage core practical, discuss difference in vitamin c content due to boiling
Use of cabbage juice. Titrating juice into DCPIP. Colour change from blue to colourless when juice added. Use of calibration curve to determine vitamin C concentration. Controlled variable is temperature. Repeat the experiment.

3) calculate percentage change, lipids, draw how a triglyceride is made, how are amylose and glycogen different, how are they adapted for function
Glycerol + 3fatty acids = triglyceride + water
Amylose is straight chain, glycogen has side branches. Is it 1 mark?
Compacts molecules. More glucose in less space in the cell.
No osmotic effect. They do not diffuse out of cells

4) Pedigree diagram to show that moyamoya is caused by dominant allele, probability of child from persons 3 and 4
50%. Need to show parental phenotypes, genotypes, gamete genotypes, possible offspring genotypes and phenotypes

5) phospholipid bilayer transport multiple choice,

6) cholesterol study in different countries, give dietary advice from table

7) Cholesterol levels, blood clot fill the gap, how could this lead to a heat attack
Blood clot blocks coronary artery. Reduced blood flow to the heart. Less oxygen and glucose reach heart muscle cells. Less aerobic respiration. Less ATP produced. Heart muscle need a lot of ATP to contract

8) draw a line for the pulmonary artery, difference between capillary and vein, diffusion of CO2 and O2 comparison, explain how mammals transport gasses
Endothelium of capillary is one cell thick, vein has multiple layers of cell.
Rate of oxygen faster? Do they really mean rate? Credit correct manipulation of figures?
Many Alveoli provide large surface area. Ventilation of alveoli maintains concentration gradient. Blood moving maintains concentration gradient. Endothelium of capillary is one cell think, short distance, helps diffusion
9) different genotypes and how they affect life expectancy, how different amino acid affects haemoglobin structure
AA life expectancy is lower than Aa because Aa have protection against infection by insect. But AA is higher than aa because aa have anemia
Aa has some protection against insect. aa have anaemia
Mutation is change to base sequence. Change in Amino acid sequence (primary structure), change in type and position of bonds between different R groups. For example, hydrogen, ionic, disulphide bonds. Change in protein 3D shape (folding). Haemoglobin binds less oxygen. Less oxygen carried to cells for aerobic respiration. Haemoglobing less soluble
(edited 7 years ago)
Reply 79
Original post by Hellper
Unofficial markscheme please.. Thank you.


You're gonna have to wait- this is a retake paper so very few people are doing it, and so it's unlikely that an unofficial mark scheme will be made until later.

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