AQA Biology B2 - Unofficial Mark Scheme

Did no one write that the athlete ran for 1 minute because wouldn't the blood rate remain high while he pays off oxygen debt?

Thats exactly what i thought!

↑↑↑ In the poll above, an answer like '> 30%' would mean between '30%' and '40%' ↑↑↑


Remember a question? Post your answers below.
Follow me and I will try and post the answers for the Chemistry and Physics exams on Wednesday and Friday.

........................................................................................................................................................................a)
i) Anaerobic means respiration without oxygen
ii) The athlete was running for 1.5 minutes.
b) How do you know it was anaerobic respiration?
The athlete produced lactic acidQuestion 2 notes: The answer could be any experiment to test how the amount of light intensity affects photosynthesis. The question stated that you did not have to write about the equipment pictured and it was just an example.Circle Cytoplasm. (1 mark)
What is an enzyme? (2 marks)
An enzyme is a substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.
Rest of question is incompleteTo improve their investigation: Use random sampling, take more samples.
With the mean average question, people seemed to be getting either 10,100 or 160,000. Different answers I know but we are not sure which is right.

Rest of question is incomplete Stem cells are undifferentiated stem cells that can potentially become any cell.
Rest of question is incomplete
This question had a lot of parts to do with alleles but it was so long no one can really remember it.These weren't the only ones but they're the ones I have seen posted the most.

Rest of question is incompleteThe sperm cells were produced in the testes by Meiosis. The embryo divided by Mitosis.
For the question about the size of each cell:Rest of question is incompleteHow can scientists prove the foxes originated from the same species?
The scientists could breed 2 of the foxes and see if they produce fertile offspring. (Offspring which can reproduce)
How are the foxes different species?
Foxes, Geographical isolation. Adapted differently. Mutation, So unable to breed. Different species.
Why were the foxes on the 3 islands varied but still the same species?
The islands have similar conditions so the two species adapted similarly and were so similar they could still interbreed so were still of the same species.On the question about a mother and father who had 2 children we were asked about these:

Parents genotype
Parents phenotype
Gametes

Offspring genotypes
Offspring phenotypes

Anyone who knows the answers to these, please message me on twitter NacoRBLX, thanks!

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Note: The questions may not be in the right order.

This is a mix of my answers and those of the community but they are not guaranteed to be correct.

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for disadvantage for peoxide one i put its a chemical so it can mix with the milk which could harm humans if we drink it would that get me the marks

The father question. A lot of people got mixed up with genotypes, phenotypes and gametes. It was an easy 5 marker if you understood it properly
Phenotype - The characteristic (e.g. brown hair, red hair)
Genotype - The alleles (e.g. Bb bb BB)
Gametes - The offsprings genotype

Great exam btw

Me too, hope it was right

1 Anaerobic is without the presence of oxygen, he ran for 1.5 minutes, and the level of lactic acid was higher at the end, 18dm3. Epithelial tissue cover the inside and outside of the stomach, glandular realises digestive juices, muscular churns up food.
2. Put the pondweed in a test tube, fill up a beaker with water, put the test tube in the beaker, use a ruler to measure bubbles, use a timer to measure how long the light is on for, move away the light at the same intervals. Control variables- Time and distance of the light. I know that you aren't supposed to add equipment like I did, but it said that these are SOME of the things you may use, and I had a thick moment and started adding things😑
3. Enzymes are biological catalysts made of proteins. They speed up reaction without being used up in the process. Advantage- Can be done at low temperatures and can be reused. Disadvantage- Enzymes can denature easily, due to things like pH.
4. Do the maths stuff (can't remember any) and the improvements are 1. Do more samples 2. Place the quadrants randomly to eliminate bias and 3. Can't remember😐
5. Talk about two dominant alleles or one dominant and one recessive for the mother, and two recessive a for the father. The ginger one was 25% chance of a ginger and a 50% chance for the polydactyl one.
6. Advantages and disadvantages ( accidentally wrote those in question 3)
7. I had no idea what pictograms were, but the bottom answer was MITOSIS.
8. Geographical isolation, survival of the fittest, natural selection and the passing on of favourable alleles. And then the last question was that the conditions are similar on the islands and there hasn't been enough time for evolution.

The circle question was CYTOPLASM

That's what I got anyway. I've probably gotten some wrong, put some in the wrong order or missed some out.😳

Me too, hope it was right

for disadvantage for peoxide one i put its a chemical so it can mix with the milk which could harm humans if we drink it would that get me the marks

Thanks, someone else has sent me this and I updated the mark scheme It seems that people found this was the hardest question on the paper.

↑↑↑ In the poll above, an answer like '> 30%' would mean between '30%' and '40%' ↑↑↑


Remember a question? Post your answers below.
Follow me and I will try and post the answers for the Chemistry and Physics exams on Wednesday and Friday.

........................................................................................................................................................................a)
i) Anaerobic means respiration without oxygen
ii) The athlete was running for 1.5 minutes.
b) How do you know it was anaerobic respiration?
The athlete produced lactic acidQuestion 2 notes: The answer could be any experiment to test how the amount of light intensity affects photosynthesis. The question stated that you did not have to write about the equipment pictured and it was just an example.Circle Cytoplasm. (1 mark)
What is an enzyme? (2 marks)
An enzyme is a substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.Rest of question is incompleteTo improve their investigation: Use random sampling, take more samples.
With the mean average question, people seemed to be getting either 10,100 or 160,000. Different answers I know but we are not sure which is right.

Rest of question is incomplete Stem cells are undifferentiated stem cells that can potentially become any cell.
Rest of question is incomplete
This question had a lot of parts to do with alleles but it was so long no one can really remember it.

I am not sure if the following answer was on the polydactyly question but here are our redicted answers:Parents genotype: Genotype: mother: Bb father :BbParents phenotype: Both have brown hairGametes: ?Offspring genotype: Brother: bb Sister: BbOffspring phenotype: Brother - red hair sister - brown hairThese weren't the only ones but they're the ones I have seen posted the most.

Rest of question is incompleteThe sperm cells were produced in the testes by Meiosis. The embryo divided by Mitosis.
For the question about the size of each cell:Rest of question is incompleteHow can scientists prove the foxes originated from the same species?
The scientists could breed 2 of the foxes and see if they produce fertile offspring. (Offspring which can reproduce)
How are the foxes different species?
Foxes, Geographical isolation. Adapted differently. Mutation, So unable to breed. Different species.
Why were the foxes on the 3 islands varied but still the same species?
The islands have similar conditions so the two species adapted similarly and were so similar they could still interbreed so were still of the same species.Know more answers? Please message me on twitter @NacoRBLX, thanks!


Note: The questions may not be in the right order.

This is a mix of my answers and those of the community but they are not guaranteed to be correct.

........................................................................................................................................................................

What did everyone get for the genotype, phenotype and gametes question for the mother, father and then children? I couldn't remember what a phenotype was and so I'm pretty sure I completely messed up that page
I put as the phenotype Bb and Bb and then the Genotype I put heterozygous and gametes I put XY and XX - I'm certain I've got this entire page wrong as it was something I only briefly revised and now wish I had spent more time on!


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for disadvantage for peoxide one i put its a chemical so it can mix with the milk which could harm humans if we drink it would that get me the marks

Why was it Mitosis and not meiosis? It was producing sperm cells?

The spec states that humans can develop allergies to certain enzymes, so you could get the mark

Drinking Hydrogen Peroxide can cause chemical burns in the esophagus, which can lead to scarring and even narrow it, making it more likely you'll choke.
Yes there's a 95% chance you shall get the mark.

Thanks, I'll add it to the mark scheme.

Thats exactly what i thought!