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    HOW WAS BIOLOGY 42??

    MINE WAS AMAZING!!! Expecting at least 90 inshalah! I was laughing through the entire paper at its ease =D !!! AAAAAAA!!! How was yours? Anyone know the right answers to the Ovarian follicle labelling?
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    Biology P4 random notes

    In Vitro Fertilisation (IVF) FSH is injected in woman Just before ovulation eggs are collected and matured Fertilisation → collected sperm sample is added to collected mature egg Nucleus of sperm is micro-injected into the egg Fertilisation outside the body in a plastic disc Advantage: possible...
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    Biology P4 random notes

    Structure of a Mature Sperm Cell Head: acrosome (enlarged lysosome → digestive enzymes → penetrate egg), nucleus (n) Middle piece: mitochondria, ATP needed for tail movement Tail: flagellum, movement Movement of Sperm in the Female Reproductive Tract Sperm are ejaculated into the vagina /...
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    Biology P4 random notes

    How gametogenesis differs in females "b) Unequal cell division in meiosis / 1 ovum and tiny polar bodies produced b) Primary oocytes form before birth / growth phase before birth b) Pause in meiosis at prophase I / further development suspended until puberty b) Pause in meiosis at metaphase II /...
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    Biology P4 random notes

    Gametogenesis (→Formation of Gametes) SAME in both sexes a) spermatogenesis, b) oogenesis Multiplication of diploid cells by MITOSIS Epithelium of seminiferous tubules multiplies Daughter cells are pushed towards lumen of tubule Epithelial cell inside ovary of female fetus multiplies GROWTH of...
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    Biology P4 random notes

    Pacinian Corpuscles Found in dermis of skin, joints, tendons, external genitalia, internal organs Structure Layers (maellae) of connective tissue surround Myelinated sensory neurone (nerve fibre ending) that have Stretch-mediated Na+ channels Round pacinian corpuscle has a resting potential...
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    Biology P4 random notes

    Factors Affecting the Speed of Conductance: Myelin, Axon Diameter, Temperature Impulses travel faster in myelinated neurones → SALTATORY CONDUCTION Schwann cells prevent diffusion of ions Flow of current between adjacent nodes of Ranvier \ depolarisation only at nodes of Ranvier Action potential...
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    Biology P4 random notes

    Refractory Period Represents a time during which the membrane cannot be depolarised again During repolarisation and hyperpolarisation Membrane is impermeable to Na+ ions / sodium ion channels closed Sodium ions cannot enter axon K+ ions move out as membrane is more permeable to K+ ions Membrane...
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    Biology P4 random notes

    Action Potentials And Nerve Impulses Change In Membrane Permeability Leading To The Generation Of An Action Potential Stimulus reaches threshold Voltage-regulated sodium channels open / influx of Na+ / down electrochemical gradient / +ve feedback Depolarisation / inside becomes +ve / membrane...
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    Biology P4 random notes

    The Agonistic And Antagonistic Effects Of Chemicals On Synaptic Transmission Agonists/antagonists are similar in shape to neurotransmitter Fit into specific protein receptors of postsynaptic membrane Agonists → same effect as neurotransmitter Anatoxin produced by some algae and mimics effect of...
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    Biology P4 random notes

    The Mechanisms Of Transmission At An Excitatory Synapse Nerve impulse reaches synaptic knob/presynaptic membrane/neurone Depolarisation opens Ca2+ gates / calcium ions enter Ca2+ causes vesicles containing neurotransmitter to fuse with membrane Release of neurotransmitter / into synaptic cleft /...
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    Biology P4 random notes

    Summation Several presynaptic neurones release neurotransmitter Cumulative effect reaches a threshold to depolarise postsynaptic membrane E.g. rod cells when they synapse with relay neurones in the retina Spatial summation Several impulses arrive at one neurone via several synapses Cause...
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    Biology P4 random notes

    The alleles move from one chromatid on one homologous chromosome to the corresponding non-sister chromatid on the other member of the homologous chromosome pair. http://www.youtube.com/watch?v=m2Rd6iW_Ncw (What he's doing is breaking linkage groups)
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    Biology P4 random notes

    but it says The mitotic phase is a relatively short period of the cell cycle. It alternates with the much longer interphase, where the cell prepares itself for cell division. Interphase is therefore not part of mitosis.
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    Biology P4 random notes

    divided* :O
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    Biology P4 random notes

    Neither are stages of mitosis or meiosis. Mitosis and Meiosis are NUCLEAR divisions,hence they can be divides into PMAT. Cytokinesis is the division of cytoplasm and Interphase is a stage in the Cell Cycle.
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    Biology P4 random notes

    What it really means: oxygen debt- The physiological state that exists in a normally aerobic animal when insufficient oxygen is available for metabolic requirements (e.g. during a period of strenuous physical activity). To meet the body's increased demand for energy, pyruvate is converted...
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    Biology P4 random notes

    Sigh. It's some complex. I don't know the name :(
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    Biology P4 random notes

    Oxford(iPhone app)- turnover- the rate at which goods are sold and replaced in a shop Consistent.
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    Biology P4 random notes

    "Huge" turnover means that the rate of it being used in reactions AND being synthesized again is "Huge" ATP is almost instantly used up in metabolic reactions(as it's produced), hence, is constantly being synthesized in the mitochondria. Hope you understood...
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