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    People can share their notes and advice here
    Also if you are struggling with something, post the topic.
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    have you got any notes about cell cycle and mitosis
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    (Original post by n1k35h)
    have you got any notes about cell cycle and mitosis
    Mitosis is needed for growth, repair and asexual reproduction in plants and animals.

    Growth - Multicellular organisms produce new extra cells to grow. New cells are genetically identical to the parent cell and can preform the same function.

    Repair - Damaged cells need to be replcaed by new ones to preform the same function and need to be genetically identical.

    Asexual reproduction - Single celled organisms divide to produce two daughter cells that are seperate organisms. Some multicellular organisms produce offsprin from parts of the parent.

    Stages
    Interphase - DNA Replicates

    Prophase - Chromosomes coil, shorten and thicken. They are now visible under a light microscope. The nuclear envelope breaks down.
    Centrioles move to opposite ends of the cells and form spindles.

    Metaphase - The chromesomes line up in the middle of the cell.
    They are then attached by the spindle fibres by the centromere (middle of chromosome).

    Anaphase - Replicated sister chromatids are seperated when the centromere is split.
    Spindle fibres shorten and pull the chromatids apart.

    Telophas - The seperated sister chromatids reach the poles of the cell.
    A new nuclear envelope forms around each set.
    Spindle breaks down.
    The chromosomes uncoil so they are no longer visible under a light microscope.

    Cytokinesis - The whole cell splits into two new cells, each is identical to each other and to the parent cell.
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    I have loads of typed up notes for this exam, I did it last year!
    any ideas how to attach it? they are pretty good if I do say so myself, took weeeks
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    (Original post by Mally-xo)
    I have loads of typed up notes for this exam, I did it last year!
    any ideas how to attach it? they are pretty good if I do say so myself, took weeeks
    How long are the notes, also what did you type them up on.
    You will be able to attach a word document or notepad (txt).

    Thanks btw!
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    (Original post by xMaGic)
    How long are the notes, also what did you type them up on.
    You will be able to attach a word document or notepad (txt).

    Thanks btw!
    ummm they are about 30 pages and they have pictures/diagrams that I did on Paint as well!
    I will attempt to put them up tomorrow okay? I have to go babysitting now, joy
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    (Original post by Mally-xo)
    ummm they are about 30 pages and they have pictures/diagrams that I did on Paint as well!
    I will attempt to put them up tomorrow okay? I have to go babysitting now, joy
    wow! - they seem quality notes :P
    and okay lol enjoy baby sitting.
    thanks =D
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    (Original post by Mally-xo)
    ummm they are about 30 pages and they have pictures/diagrams that I did on Paint as well!
    I will attempt to put them up tomorrow okay? I have to go babysitting now, joy
    ooooh could i have a copy too? Im so stressed for this bio exam and they would really help
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    Post random notes here, so we can remember them for exam.

    Cell membranes are made from 2 layers of phospholipids. They have a hydrophilic head and the tails are hydrophobic.
    They are fluid, so components can move freely inside. They only allow small non-polar substances through and are impermeable to large molecules and ions. Cell membranes are selectively permeable.

    Cholestrol - gives the membrane more mechanical stability by sitting between fatty acid tails making the barrier more complete.

    Glycolipids - Phospholipid molecule with a carbohydrase attached. Used for cell signalling, cell surface antigens and cell adhesion.

    Proteins - Channel and carrier. Channel proteins allow water-soluble molecules in. such as large molecule, eg. sugar. Because it cant travel directly through the membrane.

    Glycoproteins - Phospholipid molecule with a protein attached. Same function as glycolipid
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    Can someone explain membrane-bound receptors/cell signalling please?!
    I dont understand it
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    (Original post by stargirll)
    ooooh could i have a copy too? Im so stressed for this bio exam and they would really help
    (Original post by xMaGic)
    wow! - they seem quality notes :P
    and okay lol enjoy baby sitting.
    thanks =D
    righty I tried compressing the file but to no avail, it is toooo big.
    so if you guys pm me your email, I can send it via hotmail

    p.s. it appears some of the notes are missing, I obviously accidentally deleted a file, however I still have about ten pages worth of stuff.
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    (Original post by xMaGic)
    Can someone explain membrane-bound receptors/cell signalling please?!
    I dont understand it
    Recognition and communication – Receptor sites allow hormones to bind with the cell so that a cell response can be carried out. A cell can respond to a hormone only if it has a receptor for that hormone on its cell surface. They also affect cell metabolism. Glycoproteins and glycolipids may be involved in cells signalling and allow recognition by the immune system. Glycoproteins can also bind cells together in tissues.
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    I have a 50 slide revision powerpoint for OCR AS Biology last year
    If anyone wants it, just tell me how to send it and I will
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    Anyone have notes on transport in animals (especially the heart, cardiac cycle, etc)
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    (Original post by VetApplicant)
    I have a 50 slide revision powerpoint for OCR AS Biology last year
    If anyone wants it, just tell me how to send it and I will
    Is there any way you can send the powerpoint by email?
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    (Original post by shamzika)
    Is there any way you can send the powerpoint by email?
    yes, pm with your email address
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    Has anyone got a copy of the table in the January 2009 paper? I've just printed off the past paper but its been taken off due to copyright.
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    (Original post by VetApplicant)
    I have a 50 slide revision powerpoint for OCR AS Biology last year
    If anyone wants it, just tell me how to send it and I will
    ooh can you email me one too?
    has it got transport on it?

    thaaaaaanks!
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    (Original post by emmaD96)
    Anyone have notes on transport in animals (especially the heart, cardiac cycle, etc)
    Cardiac cycle;

    1. Relaxation of Ventricles and atria.
    2. Blood enters atria from veins returning to heart
    3. Atria fill with blood
    4. Atria contract (atrial systole)
    5. Blood passes into ventricles
    6. Through atrioventricilar valves
    7. Atrioventricular valves shut to prevent backflow back into atria
    8. Ventricles contract (ventricular systole)
    9. Blood passes out into arteries leaving the heart through open semilunar valves
    10. Semilunar valves shut to prevent backflow
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    can anyone teach me about xylem and phloem? and transpiration etc.
 
 
 
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