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BIOL4 Biology Unit 4 Exam - 13th June 2011 Watch

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    Are there more than 3 papers?
    I can only find three (June 10, Jan 11 and the Specimen)!!
    If anybody has more let me know. Thanks!!
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    (Original post by woods.vanessa)
    Are there more than 3 papers?
    I can only find three (June 10, Jan 11 and the Specimen)!!
    If anybody has more let me know. Thanks!!
    There's Jan 10 here That's the paper there was all the controversy over with the main HSW question (shrew and the faunagoo). It's pretty straight forward if you look at it logically, it's not asking for anything complicated!
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    (Original post by coffee345)
    When predators eat their prey, it reduces the size of the prey population.
    The predators are therefore in more intraspecific competition with each other for the fewer prey that are left.
    As a result, the predator population becomes reduced as some predators aren't able to obtain prey for survival.
    With fewer predators left, fewer prey are eaten; the prey population in turn increases.
    With more prey available, there is therefore more food - so the predator population increases again.
    Yep. You're supposed to post a question
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    guys predictions for last essay Qs cause i flopped speciation in jan and biological agent LOL thought it was pesticides
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    (Original post by INeedToRevise)
    Yep. You're supposed to post a question
    Question: Outline the processes of leaching and eutrophication
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    (Original post by SK-mar)
    If you're talking bout respiration then.....

    Electrons are transfered down the transport chain through various carrier molecules. each carrier molecule is at a lower energy level than the previous one, so energy is lost from the electrons at these stages. this energy is used to transport protons from the mitochondrial matrix into the intermembrane space of the mitochondria. this creates a proton gradient, so protons move back into the mitochondrial matrix through the enzyme ATP synthase. the energy gained from this is used to combine ADP and and an inorganic phosphate molecule to produce ATP.


    Question: What are the two main types of selection and what do they mean?
    Remember We were discussing a question

    Describe 2 ways of making ammonium ions:

    AM lookin at p95 textbook and nitrogen fixation is also one of the answer - we ve got 2 types of nitrogen fixation I guess
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    (Original post by coffee345)
    Question: Outline the processes of leaching and eutrophication
    Leeching is when are removed from soil. Nitrates then go into water courses and as the nitrates build up in the water the algae start to grow, they couldn't before because the lack of nitrates limited their growth. Due to highest nitrate concentration the algae and plants start to grow exponentially. Algae grows on the surface of the water which limits the amount of light that can penetrate through the water. Light is a limiting factor for plants and they start to die because of the lack of photosynthesis. Then saprobiotic organisms grow, these start to decompose the dead plants and use these as food source, these organisms need to respire and use the organisms, oxygen is no reduced so aerobic organisms start to die and less comp for oxygen for anaerobic organisms mean they now grow exponentially and they can decompose things more.

    What are the advantages and disadvantages of intensive rearing of livestock (6 marks).
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    (Original post by User12399)
    Leeching is when are removed from soil. Nitrates then go into water courses and as the nitrates build up in the water the algae start to grow, they couldn't before because the lack of nitrates limited their growth. Due to highest nitrate concentration the algae and plants start to grow exponentially. Algae grows on the surface of the water which limits the amount of light that can penetrate through the water. Light is a limiting factor for plants and they start to die because of the lack of photosynthesis. Then saprobiotic organisms grow, these start to decompose the dead plants and use these as food source, these organisms need to respire and use the organisms, oxygen is no reduced so aerobic organisms start to die and less comp for oxygen for anaerobic organisms mean they now grow exponentially and they can decompose things more.

    What are the advantages and disadvantages of intensive rearing of livestock (6 marks).
    Advantages:
    - More energy as lessmovement, efficient
    - No predation
    - Less chance of disease
    - Less food needed due to controlled diet, cheaper
    Disadvantages
    - Antibiotic resistance
    - Ethical concerns, unnatural for animal
    - Reduced genetic diversity

    What are the assumptions for Hardy- Weinberg (4 marks)
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    (Original post by INeedToRevise)
    Advantages:
    - More energy as lessmovement, efficient
    - No predation
    - Less chance of disease
    - Less food needed due to controlled diet, cheaper
    Disadvantages
    - Antibiotic resistance
    - Ethical concerns, unnatural for animal
    - Reduced genetic diversity

    What are the assumptions for Hardy- Weinberg (4 marks)
    -No emigration/immigration
    -No natural selection
    -No gene flow
    -Large population size
    -No mutuations
    -Random mating
    Outline the stages in the carbon cycle(5 Marks)
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    (Original post by INeedToRevise)
    Advantages:
    - More energy as lessmovement, efficient
    - No predation
    - Less chance of disease
    - Less food needed due to controlled diet, cheaper
    Disadvantages
    - Antibiotic resistance
    - Ethical concerns, unnatural for animal
    - Reduced genetic diversity

    What are the assumptions for Hardy- Weinberg (4 marks)
    There are no mutations;
    Large population size;
    Population is isolated - no flow of alleles into or out of population;
    Random mating between individuals;
    No selection - all alleles equally likely to be passed to next generation.

    What are the differences between an agricultural and natural ecosystem? (6 marks)
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    (Original post by Ebony_x)
    -No emigration/immigration
    -No natural selection
    -No gene flow
    -Large population size
    -No mutuations
    -Random mating
    Outline the stages in the carbon cycle(5 Marks)
    When there is a high concentration of carbon dioxide in the atmosphere: CO2 diffuses into oceans and photosynthetic aquatic organisms use CO2 to build up their macromolecules in their bodies.
    Energy is transferred to other organisms in the food chain by primary consumers feeding on the producers.
    When these organisms die - decomposers, more specifically, saprobiotic microorganisms secrete enzymes onto the dead organic matter by extra cellular digestion. This breaks it down into more smaller, soluble molecules which are absorbed by the saprobionts by diffusion.
    CO2 is released back into atmosphere by respiration.
    If decay is prevented, shells and bones sink to bottom of ocean and form sedimentary rocks such as limestone. When these are weathered, CO2 is returned back to the atmosphere.

    Describe the mark release recapture method (4 marks)
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    (Original post by cobra2k10)
    Hey, I dont have any revision notes fo this unit yet and when i get hold of some, ill upload them right away. I do have the AQA nelson thornes text book answers for this unit as they are not in the book. They may be of some help to you!

    Any idea of where i can find the nelson thorne Qs. I downloaded your pdfs thinking they were answers and questions lol.

    Btw i dont actually have the NT textbook
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    (Original post by coffee345)
    When there is a high concentration of carbon dioxide in the atmosphere: CO2 diffuses into oceans and photosynthetic aquatic organisms use CO2 to build up their macromolecules in their bodies.
    Energy is transferred to other organisms in the food chain by primary consumers feeding on the producers.
    When these organisms die - decomposers, more specifically, saprobiotic microorganisms secrete enzymes onto the dead organic matter by extra cellular digestion. This breaks it down into more smaller, soluble molecules which are absorbed by the saprobionts by diffusion.
    CO2 is released back into atmosphere by respiration.
    If decay is prevented, shells and bones sink to bottom of ocean and form sedimentary rocks such as limestone. When these are weathered, CO2 is returned back to the atmosphere.

    Describe the mark release recapture method (4 marks)
    Firstly a sample is captured, the first captured organisms are marked and counted using some kind of marker, the they are released, after some time the same species of organisms are captured, counted and out of the counted how many are marked. Then a population is estimated by using the calculation total in first * total in second / number marked that are recaptured in second.

    Explain the process of the light independent stage (6 marks)

    Also why did this receive a downvote? Is it wrong? http://www.thestudentroom.co.uk/show...&postcount=134
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    (Original post by User12399)
    Firstly a sample is captured, the first captured organisms are marked and counted using some kind of marker, the they are released, after some time the same species of organisms are captured, counted and out of the counted how many are marked. Then a population is estimated by using the calculation total in first * total in second / number marked that are recaptured in second.

    Explain the process of the light independent stage (6 marks)

    Also why did this receive a downvote? Is it wrong? http://www.thestudentroom.co.uk/show...&postcount=134
    I wouldn't say the the same species of organisms are captured. It makes it seem like you are going to get the same sample from before. I would say a second sample of the same species would be taken after some time. Make sure you say that the marking doesn't make the organisms more liable for predation. I would just add it it, you never know with AQA.

    1) Occurs in the stroma
    2) RuBP combines with CO2 using an enzyme
    3) Converts into 2 molecules of GP
    4) GP is reduced to TP using reduced NADP from light dependent reaction.
    5) TP is used to make useful substances and glucose
    6) ATP is needed to regenerate RuBP so the cycle can repeat.

    What problems does deforestation cause?
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    (Original post by User12399)
    Firstly a sample is captured, the first captured organisms are marked and counted using some kind of marker, the they are released, after some time the same species of organisms are captured, counted and out of the counted how many are marked. Then a population is estimated by using the calculation total in first * total in second / number marked that are recaptured in second.

    Explain the process of the light independent stage (6 marks)

    Also why did this receive a downvote? Is it wrong? http://www.thestudentroom.co.uk/show...&postcount=134
    It happens in the stroma of the chloroplast:
    1)RuBP combines with CO2 using an enzyme, rubisco, to form 2 glycerate 3 phosphate molecules
    2) the 2 glycerate 3 phosphate are reduced to 2 triose phosphate molecules using reduced NADP and ATP from the light dependent stage of photosynthesis.
    3) the NADP is regenerated and goes back to the grana in the light dependent stage to accept more hydrogen.
    4) some of the triose phosphate is used to form organic molecules such as glucose, sucrose etc.
    5) however, most of the triose phosphate is used to reform the RuBP - about 5 in 6 molecules.
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    (Original post by INeedToRevise)
    I wouldn't say the the same species of organisms are captured. It makes it seem like you are going to get the same sample from before. I would say a second sample of the same species would be taken after some time. Make sure you say that the marking doesn't make the organisms more liable for predation. I would just add it it, you never know with AQA.

    1) Occurs in the stroma
    2) RuBP combines with CO2 using an enzyme
    3) Converts into 2 molecules of GP
    4) GP is reduced to TP using reduced NADP from light dependent reaction.
    5) TP is used to make useful substances and glucose
    6) ATP is needed to regenerate RuBP so the cycle can repeat.

    What problems does deforestation cause?
    It increases the CO2 concentration in the atmosphere as it reduces photosynthesising biomass on Earth.

    I cant think of anything else @[email protected]

    How would you sample buttercups on a field? (2 marks)
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    (Original post by coffee345)
    It increases the CO2 concentration in the atmosphere as it reduces photosynthesising biomass on Earth.

    I cant think of anything else @[email protected]

    How would you sample buttercups on a field? (2 marks)
    How about habitats being destroyed? .....species diversity?
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    (Original post by INeedToRevise)
    I wouldn't say the the same species of organisms are captured. It makes it seem like you are going to get the same sample from before. I would say a second sample of the same species would be taken after some time. Make sure you say that the marking doesn't make the organisms more liable for predation. I would just add it it, you never know with AQA.

    1) Occurs in the stroma
    2) RuBP combines with CO2 using an enzyme
    3) Converts into 2 molecules of GP
    4) GP is reduced to TP using reduced NADP from light dependent reaction.
    5) TP is used to make useful substances and glucose
    6) ATP is needed to regenerate RuBP so the cycle can repeat.

    What problems does deforestation cause?
    hey,
    i noticed on your signiture you've applied for pharmacy - i've applied for pharmacy too

    what is your firm?
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    (Original post by aGeorgie)
    How about habitats being destroyed? .....species diversity?
    yeah, like niches and habitats?

    forgot about those!
    lol
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    (Original post by coffee345)
    yeah, like niches and habitats?

    forgot about those!
    lol
    ha yeah sometimes it's easy to forget the obvious. How about....

    Describe the part played by the inner membrane of a mitochondrion in producing ATP
 
 
 
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