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

Original post by kosmooos

I think the paper was repetition of past papers

I'm expecting a reasonably high grade boundary as it wasn't very difficult.

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Reply 21

gameofthrones1

Original post by melanin101

It was something like: "DIscuss the life expectancy of people who have an Aa (heterozygous) genotype". I have bad memory :frown:

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That Fick's law question (gas exchange in mammals) question hurt my hand.

Bare bones of my answer:
- Intercostal + Diaphragm muscles contract and relax forcing air in and out therefore removing CO2 and taking in more O2. This keeps the concentration gradient steep by continually supplying more O2 and expelling CO2.
- The surface area of the alveoli is massive. Very large respiratory surface therefore lots of area for gas exchange to happen. This increases rate of diffusion.
- Diffusion pathway is extremely short as single walled alveoli are in very close vicinity to walls of single celled capillaries. Short pathway for CO2 and O2 to diffuse through therefore increasing rate of diffusion.
- Details on lungs, air goes through trachea -> bronchi -> bronchioles -> millions and millions of alveoli with many bulbous sacs.

I think the key to this question was talking about how our lungs maximise rate of diffusion. In this case, keeping the top of the fraction (conc. gradient & surface area) large and the bottom of the fraction (diffusion pathway) small.

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What did you guys write on the effect of boiling on Vitamin C?

I wrote the same as you for that question. For the vitamin C one, I went about it as how temperature effects the enzyme that oxidises vitamin C. For the first part I spoke about how as the temperature increases, there are more collision and subsequently less vitamin C. For the question about putting it straight into boiling water, I spoke about the enzyme being denatured straight away and so it doesn't oxidise vitamin C; that's why there is a lot of vitamin C still present.

Not sure if that was correct though, what did you put?

Reply 22

melanin101

11

Original post by atherosclerosis

What do you think the grade boundaries will be like: the ones I found most difficult was explaining why it was a dominant disorder, why there was less vitamin c loss from boiling than from cold water to boiling

Prob kinda high. Idk how they're calculated but since we're all resits, our marks will be higher which will probably push up the grade boundaries. + this test wasn't hard, it was a standard bio paper.

Reply 23

Original post by gameofthrones1

I wrote the same as you for that question. For the vitamin C one, I went about it as how temperature effects the enzyme that oxidises vitamin C. For the first part I spoke about how as the temperature increases, there are more collision and subsequently less vitamin C. For the question about putting it straight into boiling water, I spoke about the enzyme being denatured straight away and so it doesn't oxidise vitamin C; that's why there is a lot of vitamin C still present.

Not sure if that was correct though, what did you put?

I said that as well for the straight into boiling water question

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Reply 24

melanin101

11

Original post by gameofthrones1

I wrote the same as you for that question. For the vitamin C one, I went about it as how temperature effects the enzyme that oxidises vitamin C. For the first part I spoke about how as the temperature increases, there are more collision and subsequently less vitamin C. For the question about putting it straight into boiling water, I spoke about the enzyme being denatured straight away and so it doesn't oxidise vitamin C; that's why there is a lot of vitamin C still present.

Not sure if that was correct though, what did you put?

I just wrote some bs about how an increase in temp will change the molecule (e.g: bonds breaking).

The second part, even more bs.

I don't think I got any marks lol.

Reply 25

Original post by splog23

I said that boiling would break down the cell surface membrane (proteins denaturing and so forth) and so vitamin C could move out of it

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Move out from where?

Reply 26

Original post by kosmooos

Move out from where?

Inside the cells, tbh this was a question that I came back to right before the end so I'm not sure how accurate my answer is

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Reply 27

Ariasia

I ran out of time for the last Q so wrote anything that came to mind in hope of picking up some marks. But damn, that was tough. Tbh some bits were quite easy compared to other really difficult parts.

Reply 28

Original post by Silverstars123

hmm i think i answered that wrong, i wrote AA is higher becuase they have the normal alleles and Aa has the same as AA because the anemia is not expressed in the phenotype only in the genotype

It said in the question that Aa have sufficient normal red blood cells, so wouldn't it be kind of codominance? Sufficient means that they have some faulty red blood cells. it also said that their(Aa) red blood cells will burst before insect can reproduce, so they won't suffer due to insect unlike AA

Reply 29

chemica

what mark do you think for an A ? 62-4?

Reply 30

Original post by gameofthrones1

I wrote the same as you for that question. For the vitamin C one, I went about it as how temperature effects the enzyme that oxidises vitamin C. For the first part I spoke about how as the temperature increases, there are more collision and subsequently less vitamin C. For the question about putting it straight into boiling water, I spoke about the enzyme being denatured straight away and so it doesn't oxidise vitamin C; that's why there is a lot of vitamin C still present.

Not sure if that was correct though, what did you put?

For the second question I put the same! In the last moment! I can't believe this can be right, because I just read that there was an enzyme involved and said about denaturimg and less KE when cold water. Glad I am not the only one who put it. I didn't expand about a lot of vitamin C though, probably will lose a mark

Reply 31

OP

Original post by melanin101

It was something like: "DIscuss the life expectancy of people who have an Aa (heterozygous) genotype". I have bad memory :frown:

----

That Fick's law question (gas exchange in mammals) question hurt my hand.

Bare bones of my answer:
- Intercostal + Diaphragm muscles contract and relax forcing air in and out therefore removing CO2 and taking in more O2. This keeps the concentration gradient steep by continually supplying more O2 and expelling CO2.
- The surface area of the alveoli is massive. Very large respiratory surface therefore lots of area for gas exchange to happen. This increases rate of diffusion.
- Diffusion pathway is extremely short as single walled alveoli are in very close vicinity to walls of single celled capillaries. Short pathway for CO2 and O2 to diffuse through therefore increasing rate of diffusion.
- Details on lungs, air goes through trachea -> bronchi -> bronchioles -> millions and millions of alveoli with many bulbous sacs.

I think the key to this question was talking about how our lungs maximise rate of diffusion. In this case, keeping the top of the fraction (conc. gradient & surface area) large and the bottom of the fraction (diffusion pathway) small.

--

What did you guys write on the effect of boiling on Vitamin C?

For the lungs question, I wrote the bolded and also:
-alveoli provided large SA:V ratio
- constant blood supply to maintain concentration gradient
and because we were given the equation I said:
- you want the difference in concentration and SA to be as big as possible and the distance to be as small as possible which I then realated to how thatwas achieved

For vitamin:
There was an enzyme involved so I talked about optimum temperatures and then for the cold water one I said that it meant it took longer too reach optimum temperature so lower rate of reaction and less vitamin c lost

Reply 32

OP

What did people get for the first question on number of amino acids made and number of trna molecules used?

And also differences in RNA and DNA?

Reply 33

gameofthrones1

Original post by kosmooos

For the second question I put the same! In the last moment! I can't believe this can be right, because I just read that there was an enzyme involved and said about denaturimg and less KE when cold water. Glad I am not the only one who put it. I didn't expand about a lot of vitamin C though, probably will lose a mark

Yeah, I saw the enzyme in the extract and just assumed that that's what they wanted us to talk about!

Reply 34

Original post by Excuse Me!

What did people get for the first question on number of amino acids made and number of trna molecules used?

And also differences in RNA and DNA?

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)

Reply 35

Original post by Excuse Me!

What did people get for the first question on number of amino acids made and number of trna molecules used?

And also differences in RNA and DNA?

Should be 8 and 6, because 3 bases code for one amino acid, and because each tRNA molecule was 3 bases but two of the molecules were repeated, so 8-2=6

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Reply 36

OP

This may help jog memories for someone to piece together a mark scheme or to discuss answers, not sure if ive remembered everything or if order is correct

1) DNA protein synthesis, differences in DNA and RNA

2) vitamin c cabbage core practical, discuss difference in vitamin c content due to boiling

3) calculate percentage change, lipids, draw how a triglyceride is made, how are amylose and glycogen different, how are they adapted for function

4) Pedigree diagram to show that moyamoya is caused by dominant allele, probability of child from persons 3 and 4

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

8) draw a line for the pulmonary artery, difference between capillary and vein, diffusion of CO2 and O2 comparison, explain how mammals transport gasses

9) different genotypes and how they affect life expectancy, how different amino acid affects haemoglobin structure

Reply 37

gameofthrones1

Original post by Excuse Me!

What did people get for the first question on number of amino acids made and number of trna molecules used?

And also differences in RNA and DNA?

I put 8 for the first one and 8 for the second one but I think I got the second one wrong as I think it said the number of different tRNA molecules relative to the amino acids

Reply 38

How about why the study may not show link? (the question after blood clot, 5 last one)
Is it about something like:
Results are not valid because are variables need considering like age and gender. We don't know sample size
???

Reply 39

OP