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AQA Biology B2 - Unofficial Mark Scheme

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Who thought this was easy ? I thought it was average.
To make the 6 marker a fair test, I put moving the lamp back by the same distance each time- is this ok?
Original post by lucygr8y
I agree please!!!!


Me too. How did you find the exam ?
Reply 423
Avatar for Comp123
Comp123
I reckon the grade boundaries were well higher:
50 for A*
Original post by Naco88
↑↑↑ 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.
I have received a ton of answers on Twitter (@NacoRBLX) and have added a lot more to this! Thanks to everyone who has and still is sending me answers! We have made a really good community on this post today and look out for the chemistry and physics threads on Wednesday and Friday! - Naco88This mark scheme is not official and was made purely from what we saw in the exam.

AQA B2 Higher - Unofficial Mark Scheme (Updated Regularly) (Should have the last few questions of foundation)

1. Athlete Question - UPDATED
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 acid
c) How does the flow of the blood help the athlete's muscles?
Removes lactic acid, build up. Causes less fatigue. Supplies oxygen.
2. Pond Weed Question

•

Put the pond weed in the beaker,

•

Fill the beaker with water.

•

Move the light close to the pond weed,

•

Count bubbles in one minute, / Measure oxygen produced

•

Note down your results,

•

Repeat experiment but move the light closer/further away from the pond weed each time.

•

To make it a fair test, use same amount of water, use same length/volume of pond weed, time it for the same length.

Question 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.
(6 marks)
3. Enzymes question
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.

•

Muscular tissue contracts and churns food in the stomach

•

Epithelial tissue covers the stomach

•

Glandular tissue secretes hormones and enzymes

Rest of question is incomplete
4. Plantains in the field
To 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
5. Polydactyly Question - UPDATED
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 :Bb
Parents phenotype: Both have brown hair
Gametes: Mother: XY Father: XX
Offspring genotype: Brother: bb Sister: Bb
Offspring phenotype: Brother - red hair sister - brown hair

How do you know the man is heterogeneous?
He has B & b alleles.
6. Removing bacteria from milk with catalase.

•

Advantages: Catalysts can be reused

•

Disadvantages: Enzymes can denature, Hydrogen Peroxide doesn't kill all the bacteria, It could mix with/stay in the milk which could be harmful to humans.

These weren't the only ones but they're the ones I have seen posted the most.

Rest of question is incomplete
7. Meiosis & Mitosis
The sperm cells were produced in the testes by Meiosis. The embryo divided by Mitosis.
For the question about the size of each cell:

1.

6.6

2.

13.2

3.

6.6

4.

3.3

Rest of question is incomplete
8. Foxes
How 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.
I am not sure what question these answers were for)
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.
Grade Boundary Predictions

These are completely my predictions, we have decided that it was a fairly
easy paper so our boundaries are fairly high.

A* - 46 marks

A - 37 marks

B - 31 marks

C - 24 marks




Thanks for using my mark scheme : )






For the question about how the incresed blood flow would help him to run i also said that because more oxygen can now get to the muscles, less anaerobic respiration will take place, meaning less lactic acid will build up so the muscles will not feel as fatigued helping him to run? i did also put about the more glucose getting the muscles but if i put my first point ahead of the glucose point will it be discredited as it essentially 2 different ways
Wouldn't the athlete have ran for 1 minute? As he started running at 0.5 minutes and the graph started dropping at 2 minutes. So the logical answer would be 1.5, however the concentration of oxygen in the athletes blood stayed constant after 1.5 minutes. this could be because the athlete had stopped running but oxygen was still required to remove the lactic acid from the muscles. So from 0.5 to 1.5 would be 1 minute?
Reply 426
Avatar for BGRO
BGRO
1
Original post by Charlieskye
Could you put for the disadvantage of the enzyme-cause allergies



That's what I put!
Original post by qwertygasdfgh
Wouldn't the athlete have ran for 1 minute? As he started running at 0.5 minutes and the graph started dropping at 2 minutes. So the logical answer would be 1.5, however the concentration of oxygen in the athletes blood stayed constant after 1.5 minutes. this could be because the athlete had stopped running but oxygen was still required to remove the lactic acid from the muscles. So from 0.5 to 1.5 would be 1 minute?


Think like this, when you run you're heart rate doesn't just carry on increasing does it? It stops at a certain point unless you want to die and have a heart attack.

also
for this question guys:
"why is it better to use stem cells from the umbilical chord rather than the embryos in IVF
If I put less chance of rejection from stem cells from the person own umbilical cord, would I be correct? Thanks
I created an mark scheme for anyone intersted for unit 3
http://www.thestudentroom.co.uk/showthread.php?t=4157133
I was just wondering, for the question about the increase in blood flow to the athletes muscles, if I would get the marks for saying that it would mean more oxygen would get to the muscles which means that more respiration could be carried out and more energy would be released. Therefore the muscles would be able to contract to bring about movement. I didn't say anythimg about lactic acid or fatigue and I'm worried that I wont get the marks.
Quite worried about this question because I think I answered it wrong. Any thoughts ???
(edited 7 years ago)
Original post by Dauntless27
I was just wondering, for the question about the increase in blood flow to the athletes muscles, if I woukd get the marks for saying that it would mean more oxygen would get to the muscles which means that more respiration could be carried out and more energy would be released. Therefore the muscles would be able to contract to bring about movement.
Quite worried about this question because I think I answered it wrong. Any thoughts ???


That's basically what I wrote as well although I mentioned diffusion too (oxygen diffusing from air into alveolus)


Posted from TSR Mobile
Idk if this is right? Could I get some opinions on it please?:colondollar:

Basically for the 6 marker I said to measure the length of the growth of the pond weed, instead of the gas/number of bubbles given off. I did however explain how to get valid results/fair test and gave and said how to set up my apparatus.

What I'm wondering is if I'll get penalised for saying the growth of pond weed using the ruler? And by how many marks assuming my fair test explanation and apparatus was done well? Thank you!!:h:
[QUOTE="Naco88;65633517"]↑↑↑ 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.
I have received a ton of answers on Twitter (@NacoRBLX) and have added a lot more to this! Thanks to everyone who has and still is sending me answers! We have made a really good community on this post today and look out for the chemistry and physics threads on Wednesday and Friday! - Naco88This mark scheme is not official and was made purely from what we saw in the exam.

AQA B2 Higher - Unofficial Mark Scheme (Updated Regularly) (Should have the last few questions of foundation)

1. Athlete Question - UPDATED
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 acid
c) How does the flow of the blood help the athlete's muscles?
Removes lactic acid, build up. Causes less fatigue. Supplies oxygen.
2. Pond Weed Question

•

Put the pond weed in the beaker,

•

Fill the beaker with water.

•

Move the light close to the pond weed,

•

Count bubbles in one minute, / Measure oxygen produced

•

Note down your results,

•

Repeat experiment but move the light closer/further away from the pond weed each time.

•

To make it a fair test, use same amount of water, use same length/volume of pond weed, time it for the same length.

Question 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.
(6 marks)
3. Enzymes question
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.

•

Muscular tissue contracts and churns food in the stomach

•

Epithelial tissue covers the stomach

•

Glandular tissue secretes hormones and enzymes

Rest of question is incomplete
4. Plantains in the field
To 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
5. Polydactyly Question - UPDATED
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 :Bb
Parents phenotype: Both have brown hair
Gametes: Mother: XY Father: XX
Offspring genotype: Brother: bb Sister: Bb
Offspring phenotype: Brother - red hair sister - brown hair

How do you know the man is heterogeneous?
He has B & b alleles.
6. Removing bacteria from milk with catalase.

•

Advantages: Catalysts can be reused

•

Disadvantages: Enzymes can denature, Hydrogen Peroxide doesn't kill all the bacteria, It could mix with/stay in the milk which could be harmful to humans.

These weren't the only ones but they're the ones I have seen posted the most.

Rest of question is incomplete
7. Meiosis & Mitosis
The sperm cells were produced in the testes by Meiosis. The embryo divided by Mitosis.
For the question about the size of each cell:

1.

6.6

2.

13.2

3.

6.6

4.

3.3

Rest of question is incomplete
8. Foxes
How 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.
I am not sure what question these answers were for)
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.
Grade Boundary Predictions

These are completely my predictions, we have decided that it was a fairly
easy paper so our boundaries are fairly high.

A* - 46 marks

A - 37 marks

B - 31 marks

C - 24 marks




Thanks for using my mark scheme : )
[/QUOTE i beliefe that the runner ran for 1 minute because the other half a minute before the heart rate dropped was when he was repaying the oxygen debt created by anaerobic respiration
Reply 433
Avatar for MahMah
MahMah
I believe the athlete ran for 1 minute. Not 1.5 because the extra 0.5 was a straight light on the graph which represents that the runner had stopped running and was regaining his breathe back so the flow of blood remained steady for 30 seconds and then gradually decreased.
Reply 434
Avatar for MahMah
MahMah
For question 5 regarding how you know that the man was hetrozygous I believe you could also mention that Polydactylyl is an dominant allele.
Original post by MahMah
I believe the athlete ran for 1 minute. Not 1.5 because the extra 0.5 was a straight light on the graph which represents that the runner had stopped running and was regaining his breathe back so the flow of blood remained steady for 30 seconds and then gradually decreased.


yes that was my thinking as well. The blood flow stayed constant in order to remover lactic acid from the muscles.
Pretty sure that question 4 for the mean it was 160,000 lol.
Area covered = 0.25 x 0.25 x 10 = 0.625 m2
Number of plantains = 20 (in the 0.625m2)
Mean plantains per m2 = 20\0.625 = 32
Area of field = 100 x 50 = 5000 m2
Mean plantains in field = 5000 x 32 = 160000
Original post by MahMah
I believe the athlete ran for 1 minute. Not 1.5 because the extra 0.5 was a straight light on the graph which represents that the runner had stopped running and was regaining his breathe back so the flow of blood remained steady for 30 seconds and then gradually decreased.


I agree
Original post by SunnyBoys
Think like this, when you run you're heart rate doesn't just carry on increasing does it? It stops at a certain point unless you want to die and have a heart attack.

also
for this question guys:
"why is it better to use stem cells from the umbilical chord rather than the embryos in IVF
If I put less chance of rejection from stem cells from the person own umbilical cord, would I be correct? Thanks


but if you read my answer :/ i wrote the blood flow stayed constant, not that it started increasing
Original post by SunnyBoys
Think like this, when you run you're heart rate doesn't just carry on increasing does it? It stops at a certain point unless you want to die and have a heart attack.

also
for this question guys:
"why is it better to use stem cells from the umbilical chord rather than the embryos in IVF
If I put less chance of rejection from stem cells from the person own umbilical cord, would I be correct? Thanks

Yes you would

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