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AQA BIOL2 Biology Unit 2 Exam - 26th May 2011 watch

  • View Poll Results: Are you resitting this unit?
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    (Original post by cobra2k10)
    Hiya, check my other threads on here for BIOL1 and PHYA1! May be of some help!
    BIOL1: http://www.thestudentroom.co.uk/show...ighlight=BIOL1
    PHYA1: http://www.thestudentroom.co.uk/show...ighlight=phya1
    Thank you very much!!
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    Do you know what raw mark for the Biol 2 in June 2010 was an A? Today I got 63 out of 85 but don't know if it is an A or B as it is 74% but when aggregated the mark is out of 120. I found this website http://store.aqa.org.uk/over/stat_pd...UND-JUNE10.PDF but all of the numbers seem very low Any ideas?
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    (Original post by clairen886)
    Do you know what raw mark for the Biol 2 in June 2010 was an A? Today I got 63 out of 85 but don't know if it is an A or B as it is 74% but when aggregated the mark is out of 120. I found this website http://store.aqa.org.uk/over/stat_pd...UND-JUNE10.PDF but all of the numbers seem very low Any ideas?
    59/85 it says on that link for an A. I think that is accurate, considering there are not many past papers, so people will have had less practice, and also that this unit is harder than the last.
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    (Original post by SteveCrain)
    59/85 it says on that link for an A. I think that is accurate, considering there are not many past papers, so people will have had less practice, and also that this unit is harder than the last.
    Ok, Thanks
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    We need to start question & answer

    I'll start:

    How do bacteria pass antibiotic resistance to different species? (3 marks, or thereabouts)
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    (Original post by SteveCrain)
    We need to start question & answer

    I'll start:

    How do bacteria pass antibiotic resistance to different species? (3 marks, or thereabouts)
    Horizontal gene transmission. Through DNA Plasmid? Conjugation?

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    (Original post by EffKayy)
    Horizontal gene transmission. Through DNA Plasmid? Conjugation?

    yep; replication of plasmid, make it linear, pass it through the conjugation tube.

    You must now ask a question
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    anyone who has exam questions on ANTIBIOTIC USE & RESISTANCE. or exam questions for different topics in this unit.
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    Can someone please email the jan 2011 paper to me please?
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    (Original post by kotwal786)
    Can someone please email the jan 2011 paper to me please?
    yeah I dint mind, il mail u it later? Just mail me your addy?
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    Can you mail me Biology unit 2 2011 question paper too the zip won't open?, thanks
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    (Original post by SteveCrain)
    yep; replication of plasmid, make it linear, pass it through the conjugation tube.

    You must now ask a question
    I'll ask one
    Explain the water of movement in plants (12marks)
    Do this in as much detail as possible!
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    Oh also, what textbooks are people using, and is anyone learning the definitions at the back of the book?
    Do the exam questions ever have like 2 mark questions asking what something is?
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    (Original post by qwerty54321)
    I'll ask one
    Explain the water of movement in plants (12marks)
    Do this in as much detail as possible!
    Water moves into root hairs cells by osmosis, as the soil solution has a higher water potential than the root hair cell. Water travels to the endodermis via the apoplastic and symplasic pathways. The apoplastic pathway is through the cellulose cell walls of the cortex cells, and the water moves due to tension and cohesion of water molecules. The symplastic pathway is through the cortex cells, by osmosis. Casparian strip forces water from the apoplastic pathway into protoplast (cytoplasm?) of endodermal cells.

    Root pressure is created when mineral ions are actively transported into the root Xylem. This reduces the water potential of the xylem below that of the endodermis cells. Water moves in through a partially permeable membrane, by osmosis. The volume of water in the xylem increases, therefore pressure increases.

    Water moves up the Xylem due to transpiration pull. Water is evaporated from the mesophyll cells in the leaves, reducing their water potential. Water moves in by osmosis. This creates a negative pressure (tension) in the xylem. Water moves up in a continuous column. This is because water molecules cohere to one another, due to hydrogen bonding. Water molecules also adhere to the Xylem wall.

    (Add and correct where you feel necessary)

    Give 3 features of DNA that suit it to its function.
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    (Original post by SteveCrain)
    Water moves into root hairs cells by osmosis, as the soil solution has a higher water potential than the root hair cell. Water travels to the endodermis via the apoplastic and symplasic pathways. The apoplastic pathway is through the cellulose cell walls of the cortex cells, and the water moves due to tension and cohesion of water molecules. The symplastic pathway is through the cortex cells, by osmosis. Casparian strip forces water from the apoplastic pathway into protoplast (cytoplasm?) of endodermal cells.

    Root pressure is created when mineral ions are actively transported into the root Xylem. This reduces the water potential of the xylem below that of the endodermis cells. Water moves in through a partially permeable membrane, by osmosis. The volume of water in the xylem increases, therefore pressure increases.

    Water moves up the Xylem due to transpiration pull. Water is evaporated from the mesophyll cells in the leaves, reducing their water potential. Water moves in by osmosis. This creates a negative pressure (tension) in the xylem. Water moves up in a continuous column. This is because water molecules cohere to one another, due to hydrogen bonding. Water molecules also adhere to the Xylem wall.

    (Add and correct where you feel necessary)

    Give 3 features of DNA that suit it to its function.
    Nicely done. Which book do you use? Are you learning definitions?

    It is a large molecule - so can carry a lot of genetic information.
    It is stable - info can pass from one generation to the next without change.
    The two strands of DNA are only held by H bonds so are easily separated during replication and protein synthesis.

    What is antibiotic resistance?
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    (Original post by qwerty54321)
    Nicely done. Which book do you use? Are you learning definitions?

    It is a large molecule - so can carry a lot of genetic information.
    It is stable - info can pass from one generation to the next without change.
    The two strands of DNA are only held by H bonds so are easily separated during replication and protein synthesis.

    What is antibiotic resistance?
    I'm using the standard textbook with the Chinese girl on the front. There are only a few past papers on this specification which makes learning exam technique difficult. I'm not learning definitions, as I haven't known AQA to place much emphasis on those which aren't essential to an understanding of the content- transpiration, osmosis, diffusion, Ficks Law, are some of the ones you probably need to know.

    Where a bacterial cell has a mutation in base sequence, or gains DNA via conjugation, that give it resistance to a certain antibiotic. (I'm not sure of this answer, if you know a model one correct me please)

    Describe 2 ways in which species diversity is reduced. (I hate biodiversity, such an open ended topic )
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    (Original post by SteveCrain)
    I'm using the standard textbook with the Chinese girl on the front. There are only a few past papers on this specification which makes learning exam technique difficult. I'm not learning definitions, as I haven't known AQA to place much emphasis on those which aren't essential to an understanding of the content- transpiration, osmosis, diffusion, Ficks Law, are some of the ones you probably need to know.

    Where a bacterial cell has a mutation in base sequence, or gains DNA via conjugation, that give it resistance to a certain antibiotic. (I'm not sure of this answer, if you know a model one correct me please)

    Describe 2 ways in which species diversity is reduced. (I hate biodiversity, such an open ended topic )
    That sounds good. A definition is the development in microorganisms of mechanisms that prevent antibiotics killing them.

    Impact of agriculture - resources and environment dedicated to proportion of the population (i.e. the species) who are the most desirable in terms of alleles and characteristics so there is less food and stuff for the other species who have to compete and therefore are less likely to survive --> reduces s.d.
    Deforestation - loss of habitats so less survive --> reduces s.d.


    That sound okay? Hard to word...

    What is tissue fluid?
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    (Original post by qwerty54321)
    That sounds good. A definition is the development in microorganisms of mechanisms that prevent antibiotics killing them.

    Impact of agriculture - resources and environment dedicated to proportion of the population (i.e. the species) who are the most desirable in terms of alleles and characteristics so there is less food and stuff for the other species who have to compete and therefore are less likely to survive --> reduces s.d.
    Deforestation - loss of habitats so less survive --> reduces s.d.


    That sound okay? Hard to word...

    What is tissue fluid?
    A fluid surrounding cells which contains dissolved substances, and allows exchange of materials, such as carbon dioxide and oxygen between cells and capillaries. (I hope)

    Explain how the structures of blood vessels are related to their functions. (Include as much detail as possible.)
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    (Original post by cobra2k10)
    Just under 2 moths now until the exam. Hows everyones revision going? Im not sitting this exam but ill thought it will be useful for everyone who has it.
    I have attached the June 2010 and January 2011 past papers with their mark schemes for revision purposes!!! I ha to convert the BIOL2 JAN 11 QP in to a zip file as it was too large to be uploaded otherwise. The others can be found on the AQA website. Enjoy
    hey do you know where i can get this UNIT 2 bio jan 11 question paper?
    the file u uploaded isnt arobe so i cant download it

    please help, urgent!
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    Explain how the structures of blood vessels are related to their functions. (Include as much detail as possible.)[/QUOTE]

    Capillaries are very thin (only made of a single layer of endothelium) therefore there is a short diffusion pathway. this makes diffusion of oxygen and glucose into the capillary and carbon dioxide out of the capillary quicker. The diameter of a capillary is small so only one red blood cell can fit through at a time maintaining a concentration gradient for quick diffusion. There are many capillaries so the blood pressure is low and they spread out so a respiring tissue is only ever about 1mm away from a capillary.

    Arteries have muscular walls to allow vasomotor control (vasodilation and vasoconstriction) so the organism can maintain a constant body temperature. It has thick walls so it can withstand high pressures when blood is forced out of the aorta.

    Veins have valves to stop a backwash of blood, it also has a short diffusion pathway.


    How can a mutation cause cancer to develop?
 
 
 
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