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AQA Biology B2 - Unofficial Mark Scheme watch

  • View Poll Results: What do you predict your score?
    < 10%
    3.14%
    > 10%
    0.42%
    > 20%
    1.68%
    > 30%
    3.35%
    > 40%
    4.72%
    > 50%
    6.50%
    > 60%
    14.47%
    > 70%
    23.58%
    > 80%
    28.93%
    > 90%
    10.38%
    100%
    2.83%

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    Right so i'm looking at Question 4 on the unofficial mark scheme, seems you got plantains per m2 at 3.125... I'm kind of thinking otherwise:

    Quadrat is 25cm x 25cm = 0.25m x 0.25m = 0.0625m2 is the area of a single quadrat.
    0.0625m2 x 10 is equal to the area of all 10 quadrats = 0.625m2.
    20 plantains across 10 quadrats - 20 / 0.625m2 = 32 plantains per m2.
    32 x area of field (50m x 100m = 5000m2) .
    32 x 5000 = 160,000 Plantains on the field (estimate).

    I could be absolutely dead wrong, so let me know.
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    (Original post by Naco88)
    I just posted the predicted grade boundaries.

    Look in the title thread for them
    When will you be able to post a full unpredicted mark scheme with marks for all questions? I really need to see what i think i got!
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    Your quadrat question is wrong. To work out the number of plantains per quadrat. You do total number of organisms which is 20 divided by total number of quadrats which is 10. So 20/10 is 2. Meaning that you have 2 plantains per quadrat. So the total number of plantains in the whole field is 5000 x 2 which 10,100. If you revised the formula this would have been an easy question. Idk why so many people got it wrong.
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    (Original post by Bledz)
    Your quadrat question is wrong. To work out the number of plantains per quadrat. You do total number of organisms which is 20 divided by total number of quadrats which is 10. So 20/10 is 2. Meaning that you have 2 plantains per quadrat. So the total number of plantains in the whole field is 5000 x 2 which 10,100. If you revised the formula this would have been an easy question. Idk why so many people got it wrong.
    Nah, question specifically asked for plantains per metre squared, not plantains per quadrat (which would've been too simplistic). Note how each quadrat is 0.0625m2, not 1m2.
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    How did everyone work out question 7 where we had to work out the picograms for each cell in the division, starting with 6.6 picograms?
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    Could you please put how many marks each question is worth if possible please.
    (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.


    AQA B2 Higher - Unofficial Mark Scheme (Updated Regularly) (Should have the last few questions of foundation)1. Athlete Question
    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
    2.Six Mark 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.
    3.Enzymes question
    - Circle Question: Cytoplasm.

    4. Plantains, Quadrats. To improve their investigation: Use random sampling, take more samples.
    I got the number of plantains per square m at 3.125

    5.Polydactyly Question
    Stem cells are undifferentiated stem cells that can potentially become any cell.

    6. Removing bacteria from milk with catalase.
    • Advantages: Catalysts can be reused
    • Disadvantages: Enzymes can denature
    These weren't the only ones but are the ones I have seen posted the most.

    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
    8)
    Foxes, Geographical isolation. Adapted differently. Mutation, So unable to breed. Different species.
    Why were the foxes on the 3 islands varies 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)
    • Muscular tissue contracts and churns food in the stomach
    • Epithelial tissue covers the stomach
    • Glandular tissue secretes hormones and enzymes
    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 : )
    (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.


    AQA B2 Higher - Unofficial Mark Scheme (Updated Regularly) (Should have the last few questions of foundation)1. Athlete Question
    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
    2.Six Mark 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.
    3.Enzymes question
    - Circle Question: Cytoplasm.

    4. Plantains, Quadrats. To improve their investigation: Use random sampling, take more samples.
    I got the number of plantains per square m at 3.125

    5.Polydactyly Question
    Stem cells are undifferentiated stem cells that can potentially become any cell.

    6. Removing bacteria from milk with catalase.
    • Advantages: Catalysts can be reused
    • Disadvantages: Enzymes can denature
    These weren't the only ones but are the ones I have seen posted the most.

    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
    8)
    Foxes, Geographical isolation. Adapted differently. Mutation, So unable to breed. Different species.
    Why were the foxes on the 3 islands varies 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)
    • Muscular tissue contracts and churns food in the stomach
    • Epithelial tissue covers the stomach
    • Glandular tissue secretes hormones and enzymes
    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 : )
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    (Original post by poseidons)
    How did everyone work out question 7 where we had to work out the picograms for each cell in the division, starting with 6.6 picograms?
    6.6 was A, that was given by the question.
    B has undergone duplication so: 13.2
    C is the initial division: 6.6
    D is a gamete following a second division: 3.3
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    (Original post by JakeHorsey)
    Right so i'm looking at Question 4 on the unofficial mark scheme, seems you got plantains per m2 at 3.125... I'm kind of thinking otherwise:

    Quadrat is 25cm x 25cm = 0.25m x 0.25m = 0.0625m2 is the area of a single quadrat.
    0.0625m2 x 10 is equal to the area of all 10 quadrats = 0.625m2.
    20 plantains across 10 quadrats - 20 + 0.625m2 = 32 plantains per m2.
    32 x area of field (50m x 100m = 5000m2) .
    32 x 5000 = 160,000 Plantains on the field (estimate).

    I could be absolutely dead wrong, so let me know.
    This is what i got, except i did it a different way.
    25 X 25 X 10 = 650 = area of all quadrats in cm2
    You then need to divide this total by 1002 as it is in area, which is m2, not m.
    This gives us the 0.625m2 that you got and then same method from there.

    Edit: it should be 20/0.625=32 plantains per m2. You must have done this as you got the right answer but maybe used the wrong symbol when writing it out.
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    (Original post by Bledz)
    Your quadrat question is wrong. To work out the number of plantains per quadrat. You do total number of organisms which is 20 divided by total number of quadrats which is 10. So 20/10 is 2. Meaning that you have 2 plantains per quadrat. So the total number of plantains in the whole field is 5000 x 2 which 10,100. If you revised the formula this would have been an easy question. Idk why so many people got it wrong.
    I got this answer as well
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    For the first stage, I realized that if a quadrat was 1m by 1m then it'd be 1M squared.

    So 4 of the 25cm quadrats will make 1m squared

    8 will make 2 M squared

    So the 10 quadrats make 2.5 meters squared all togeather surely? My teacher agreed with me!

    If you do 0.25 x 0.25 then your answer will be 25% of 0.25?
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    (Original post by JakeHorsey)
    Right so i'm looking at Question 4 on the unofficial mark scheme, seems you got plantains per m2 at 3.125... I'm kind of thinking otherwise:

    Quadrat is 25cm x 25cm = 0.25m x 0.25m = 0.0625m2 is the area of a single quadrat.
    0.0625m2 x 10 is equal to the area of all 10 quadrats = 0.625m2.
    20 plantains across 10 quadrats - 20 + 0.625m2 = 32 plantains per m2.
    32 x area of field (50m x 100m = 5000m2) .
    32 x 5000 = 160,000 Plantains on the field (estimate).

    I could be absolutely dead wrong, so let me know.
    I don't understand how the area of the quadrat can be smaller than one side of the quadrat?
    • Thread Starter
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    (Original post by 11masanda002)
    When will you be able to post a full unpredicted mark scheme with marks for all questions? I really need to see what i think i got!
    All we can go on is what people have seen in the exam. AQA won't release anything for about 6 months.
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    Yeah marks would be helpful???
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    Quadrat q is 160000
    for all those who got 1600 im sorry
    0.25*0.25*10=0.625
    if u did 25*25*10 and then divided by 100 thats wrong
    if 100cm= 1m
    then 10000cm2=1m2
    so u do 6250/10000=0.625
    20/0.625=32
    32*5000=160000
    hope you all did well. Peace
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    (Original post by babymarima)
    I don't understand how the area of the quadrat can be smaller than one side of the quadrat?
    It's not: remember, they're using different units. m is a unit of length while m2 is a unit of area. I'll admit it seems weird with decimals, but you've just got to accept they're completely different measurements.
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    How many marks was the quadrant questions?

    Posted from TSR Mobile
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    (Original post by Kesavan2000)
    For the six mark I wrote basically the experiment (roughly) with a potometer. I said leave it over night... lamp different distances etc. But measure the difference in the water and calculating the amount of water used by the plant in photosynthesis

    Someone please tell me I'll get the marks

    Posted from TSR Mobile
    I did a similar experiment of measuring the amount of water before and after. I put three different beakers with the pondweed in different places like dark place, direct sunlight and another with the lamp and sunlight. After like a day look at how much water was used in each one. I think we can get marks as it is proving how different light intensities effect rate of photosynthesis.

    Hope this helps
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    (Original post by trollface54)
    Quadrat q is 160000
    for all those who got 1600 im sorry
    0.25*0.25*10=0.625
    if u did 25*25*10 and then divided by 100 thats wrong
    if 100cm= 1m
    then 10000cm2=1m2
    so u do 6250/10000=0.625
    20/0.625=32
    32*5000=160000
    hope you all did well. Peace
    Yep, thats it. A little different to my method but the right answer for sure.
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    Does anyone think the athlete ran for 1 minute because the blood flow stopped increases after this, and it stayed level to repay oxygen debt?

    and for the disadvantage of the enzyme, i said the catalase would have a high initial cost? do you think they would accept answers other than it didn't kill all of the bacteria?
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    (Original post by JakeHorsey)
    Right so i'm looking at Question 4 on the unofficial mark scheme, seems you got plantains per m2 at 3.125... I'm kind of thinking otherwise:

    Quadrat is 25cm x 25cm = 0.25m x 0.25m = 0.0625m2 is the area of a single quadrat.
    0.0625m2 x 10 is equal to the area of all 10 quadrats = 0.625m2.
    20 plantains across 10 quadrats - 20 + 0.625m2 = 32 plantains per m2.
    32 x area of field (50m x 100m = 5000m2) .
    32 x 5000 = 160,000 Plantains on the field (estimate).

    I could be absolutely dead wrong, so let me know.
    Thanks for this. I have changed the mark scheme with the 2 most common answers.
 
 
 
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