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

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1) DNA protein synthesis, differences in DNA and RNA
Number of amino acids: 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

This looks good but for 7 you haven't said how the lack of oxygen and blood will make the heart cells die and cause a heart attack. For 8 they ask for rate of diffusion and the concentration gradient for oxygen is greater so oxygen rate would be faster.

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Reply 81

kosmooos

Original post by splog23

Overall you agree? If you remember any other questions, we can discuss them

Reply 82

splog23

Original post by kosmooos

Overall you agree? If you remember any other questions, we can discuss them

Oh I've just noticed the number of amino acids is 8, not 6. The number of tRNA molecules is 6.

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Reply 83

Excuse Me!

For the question after blood clotting where it asked suggest how blood clotting could lead to a heart attack,

What did everyone out?

I talked about atherosclerosis, is that right?

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Reply 84

gameofthrones1

Original post by splog23

66 I suspect.

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I personally think that's a bit far-fetched, you have to still take into account that it is very very easy to drop an average of 2/3 marks on each question - this is the reason why all bio grade boundaries are so low, so that realistically already puts the chance of it being that high very low. I would say your points about the resit and the mash up of past paper questions are correct, but I would predict between 62-64 for an A and 70-72 for 120ums.

I might be wrong though

Reply 85

Excuse Me!

Original post by splog23

Oh I've just noticed the number of amino acids is 8, not 6. The number of tRNA molecules is 6.

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This is what I put phew.

6 different amino acids because some of the triplets were identical.

8 tRNAs because although some of the amino acids in the chain are the same, one tRNA is still required to take each one to the mRNA.

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Reply 86

splog23

Original post by Excuse Me!

Not really, although you may get a mark as a blood clot does narrow the vessel. You should talk about how the blood clot can detach and block up the vessels leading to the heart, which stops it from receiving blood. This will lead to the death of heart cells and can cause heart attacks.

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Reply 87

kosmooos

Original post by splog23

Oh I've just noticed the number of amino acids is 8, not 6. The number of tRNA molecules is 6.

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That's what I meant. 8 in first, 6 in second part of questions worth one mark

Reply 88

kosmooos

Original post by splog23

Oh I've just noticed the number of amino acids is 8, not 6. The number of tRNA molecules is 6.

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I edited the mark scheme so it doesn't cause confusion

Reply 89

Aleksandrinaa

Original post by kosmooos

That's what I meant. 8 in first, 6 in second part of questions worth one mark

Do you remember how many marks overall was the last question (about West Africa)?

Reply 90

kosmooos

Original post by Aleksandrinaa

Do you remember how many marks overall was the last question (about West Africa)?

the very last part was 4 and small parts were 2-3 marks worth each

Reply 91

olaf525

You guys think there will be high grade boundaries ?

Reply 92

Aleksandrinaa

What did the 4 marker ask? I ran out of time and don't really remember :frown:

Reply 93

splog23

Original post by Aleksandrinaa

Do you remember how many marks overall was the last question (about West Africa)?

The question was worth 10 marks in total. The 4 marker was on how a change in an amino acid could affect the structure and function of haemoglobin.

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Reply 94

SohaXO

Original post by splog23

The question was worth 10 marks in total. The 4 marker was on how a change in an amino acid could affect the structure and function of haemoglobin.

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Awkward.... it was 8 marks in total, with 2 2 mark questions and one 4 marker :smile:

Reply 95

splog23

Original post by SohaXO

Awkward.... it was 8 marks in total, with 2 2 mark questions and one 4 marker :smile:

Oh yeah, my bad :redface:

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Reply 96

Aleksandrinaa

Original post by SohaXO

Awkward.... it was 8 marks in total, with 2 2 mark questions and one 4 marker :smile:

and what did you get for the % question based on vitamin c? :smile:

Reply 97

Silverstars123

Original post by chemica

christ, I do think it will be pretty high. bye bye A

last year it was 58 in as and 60 in A2, i dont think it will be much different maybe 60 but wouldn't have thought it will be higher than that

Reply 98

splog23

Original post by Aleksandrinaa

and what did you get for the % question based on vitamin c? :smile:

74. 6% if you mean the cabbage one

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Reply 99

username2190247

Original post by splog23

66 I suspect.

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Lmaoooo which planet are you on 😂😂😂 grade boundaries have never been that high and biology papers always seem easy once you're done with them. It will probably be around 60 for an A.