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    ooh god i dont think we've learnt pigments in that much detail on my course!
    What does it mean exactly, just that it absorbs molecules and carries them etc?
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    Nor have we!!!! Its just one of the essay titles on biologymad which is aimed at AQA A!!!!!! Fingers crossed we don't get an essay on it lol.
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    yeah hope not otherwise there goes my place at uni
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    You have to remember, they cannot ask you a question which you have no idea about, example, write an essay on lipid digestion, reason, its too damn simple

    5 marks most, they cannot test your understanding on that essay.

    Same goes for pigments, we dont need to know what a "pigment" is from our spec, so they cant ask that question.

    Im guessing that it will be something to do with heart/breathing system or homeostasis or energy transfer (remembering they have to leave the question wide enough so you can talk about work we have done in different modules.)
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    I found the questions that came up in jan 05, not sure if everyone has already seen them but ive only just found them so ill put em up

    1) Negative feedback and its importance in biology
    2) Condensation and hydrolysis and their importance in biology
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    (Original post by Looontag)
    What about the role of pigments in living organisms?!!!

    The pigments I know of are haemoglobin, myoglobin, chlorophyll, rhodopzin and iodopsin.

    In for example myoglobin would talking about its loading and unloading tensions etc. be talking about the role of the pigment???!!!! I thought pigments were just the colour lol.

    Are there any more pigments that we are taught about??
    Lol now your worrying me, if that comes up i am absolutely screwed!

    Homeostasis, or cardiac would be nice
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    (Original post by johnwarneruk)
    Lol now your worrying me, if that comes up i am absolutely screwed!

    Homeostasis, or cardiac would be nice
    i doubt it would be on homeostasis as the qn in jan was the importance of negative feedback which involves homeostasis largely. having sed that u neva know with AQA
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    OMG, i am totally freaking out now! My brain doesnt hold information from years ago! I cannot answer sum of those questions from the past papers AT ALL!
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    ^^ totally agree wid u...

    i shud have not opened this thread, coz now im worried ... >> pigments and cardiac?? wtf ...thats zero for me lol and isn't cardiac jus mod 1> , maybe linked with 6 but thats it
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    OK, THIS MIGHT BE USEFUL.

    I've just got off the phone to my resident biology genius / friend.
    She talks to the teachers way too much, and is way too good at biology (285UMS for AS or something ridiculous) either way here is the 4 topics she is preparing and our teachers think will come up:

    Transport - general transport including heamoglobin etc etc..
    Movement through membranes - diffusion, facilitated, ion channels, active transport etc..*
    Lipids - Structure and function
    Protiens - Structure and function *


    The *'s were asked before in the specemin papers, but have not ever been asked in a real paper.

    Gives me some direction at least, will prepare those also..
    Seems everyone thinks lipids is coming up... ohdear.. i suck at lipids.

    Membrane transfer would be lovely.
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    ^^ very helpful gives me sum confidence

    Transport - general transport including heamoglobin etc etc..
    ^^ could you elaborate on that one plz..im confused

    Movement through membranes - diffusion, facilitated, ion channels, active transport etc..*
    ^^do you meant one of those ways of movements or the entire movement via membrane??
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    (Original post by johnwarneruk)
    OK, THIS MIGHT BE USEFUL.

    I've just got off the phone to my resident biology genius / friend.
    She talks to the teachers way too much, and is way too good at biology (285UMS for AS or something ridiculous) either way here is the 4 topics she is preparing and our teachers think will come up:

    Transport - general transport including heamoglobin etc etc..
    Movement through membranes - diffusion, facilitated, ion channels, active transport etc..*
    Lipids - Structure and function
    Protiens - Structure and function *


    The *'s were asked before in the specemin papers, but have not ever been asked in a real paper.

    Gives me some direction at least, will prepare those also..
    Seems everyone thinks lipids is coming up... ohdear.. i suck at lipids.

    Membrane transfer would be lovely.
    there was a protien question in the jan 04 paper 'How amino acids get from a protien in a persons food to becoming a part of human protien in that person' not exactly discuss the structure and function of protiens, but quite similar. membrane transfer does sound good... a bit too good to be tru? and in unit 4 wasnt there stuff about lipids?? was that their way of sayin 'hey revise lipids for friday' or 'dont bother with lipids for the synoptic'... guess we'll find out on friday...
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    wasnt there stuff about lipids?? was that their way of sayin 'hey revise lipids for friday' or 'dont bother with lipids for the synoptic'... guess we'll find out on friday...
    haha thats exactly what i thought...

    but having said that, there were no enzymes question in mod 6...so...
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    January 2005, AQA B questions were:

    Enzymes and their importance in plants and animals and How microscopes contributed to out understanding of living organisms.

    So I doubt we will get enzymes on A this year at least (although it would be great if we did!!!!)
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    By transport it could be something such as:
    "Explain how different chemicals and messages are transported throughout the human body"
    Of course i'm just speculating with that one, but it's the general idea.

    I meant the entire membrane... yah that would be very easy.

    I hope protiens doesnt come up, and i hope fats dosent come up to be honest im not great at either.

    Of course they could as a really off the wall question, past ones being "Explain how bacteria affect human lives" "Explain the different roles of microorganisms in ecology" etc etc... but it cant do any harm revising the other stuff even if we do get a random question
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    yeh what we don't want is two hard essays lol... one easy and one hard, obviouley we know what to pick ya get me...

    what about the fisrt 2 questions... what yall think they can ask? like wat topic would they touch and link upon??
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    Is the phosphlipid bilayer in plants the same as in mammals???!!!!
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    Transport could be about gas exchange/ dissociation of O2, tranasporting h+ and hydrogencarbonate ions in the blood, vesicles and their uses (ie.. neureotransmitter), link in to how the fetus gets its nutrients etc.
    Not sure but it does seem like a likely Q so i will def plan for it in a sec :p:
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    (Original post by Looontag)
    Is the phosphlipid bilayer in plants the same as in mammals???!!!!
    im guessin so theyre both eukaryotic arent they? but obviosuly the plant has a cell wall surrounding its main cell membrane :p:
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    here is my attempt at linking the basics to each topic. just thought id post it up in case it would help anyone!

    Tertiary structure of proteins - Shape determined by sequence of amino acids. The secondary structure is produced by hydrogen bonds between the amino acid residues. TERTIARY STRUCTURE when the secondary structure is further folded to give a complex globular shape. Enzymes such as carbonic anhydrase, in acrosome, digestive enzymes, neurotransmitter.



    Membrane receptors - proteins function as receptors/channels etc to allow movement of ions. Humoral immunity (complementary T-helper cells to the antigen presented on macrophage). Beta blockers block beta receptors so agonists cannot bind to it. Monoclonal antibodies attach only to tumour markers, so attach to cancer cells. Synapses, epithelial cells, receptors for hormones.


    Movement across membranes facilitated diffusion - large molecules and charged ions cross through proteins - unlike oxygen and carbon dioxide. Formation of tissue fluid. Calcium ions enter sperm membrane during acrosome reaction - releases enzymes to digest jelly coat. placenta - villi folded into microvilli, counter-current system, short diffusion path. Contains mitochondria for ATP needed for AT of amino acids. Senescence causes myelin sheath surrounding axon to become thinner - more ions leak out of nerve cell. Water potential in small intestine lower in the first part due to Na+ and Cl- ions, water added to gut. Then ions pumped out into epithelial cells à raising water potential. So water moves back out by osmosis. Amino acids pass into epithelial cells via facilitated diffusion with Na+ ions. Glucose absorbed by AT - passes into capillaries via facilitated diffusion. Lipids pass into epithelial cells via micelles, resynthesised then into lacteals. resting potentials maintained by: phospholipid bilayer, voltage-sensitive gates shut. Large negatively charged protein molecules prevent incoming Cl- ions. Sodium-potassium pump. Saltatory conduction caused by myelin sheath preventing diffusion of ions, so AP jumps from one node to another.



    Enzymes Enzyme reduced activation energy. ES Complex and induced fit theory. Competitive inhibitors. To diagnose and control disease e.g. glucose oxidase & peroxidase, absence of enzymes in faeces - chronic pancreatitis. High levels of enzymes in blood - acute pancreatitis. saprobionts secrete enzymes onto compounds to break them down. Nitrogenase catalyses reduction of nitrogen to ammonia. (nitrogen fixation). Hydrolases such as maltase/lactase/dipeptidase/proteases/lipase.



    SA/Volume ratio larger the animal the smaller it is. Large animals need body shape with large surface area / specialised gas exchange system or a blood system. Affects BMR of people - large = more heat lost.


    DNA/genetic code nucleotides joined up by hydrogen bonds. Non overlapping and degenerate. Carcinogens make mutation of tumour suppressor genes more likely. Gametogenesis = mitosis-growth-meiosis-maturation. Oogenesis not completed until fertilisation and is unequal (polar bodies). In haemoglobin, DNA substitution causes sickle cell anaemia.


    Translation/transcription mRNA to proteins with help of tRNA. Antibiotics can prevent DNA transcription/mRNA translation in bacterial cells.



    Basic genetics DNA replication via DNA polymerase. DNA à enzymes à metabolic pathway influences phenotype. Inheritance - co dominance/multiple alleles/dihybrid/sex linkage.


    Genetic engineering Isolating gene via complementary DNA, reverse transcriptase and mRNA, DNA probes. Cutting gene out through restriction endonucleases (sticky ends). Vector = plasmids. Antibiotic gene for resistance.


    Transport principles Diffusion and water potential. Haemoglobin pigment transports o2. Made of 4 subunits containing -haem and globin. Bohr shift (increases pp of CO2). Carbon dioxide reacts with water to form carbonic acid. Catalysed by carbonic anhydrase in red blood cells à splits into hydrogen ion and hydrogencarbonate ion. ß diffuse out into plasma, to correct this Cl- ions move into red blood cell. H+ ions carried by buffer solution haemoglobin.


    Use of tracers DNA probes - electrophoresis separates DNA fragments by their size. (fragments made by restriction enzymes).


    Photosynthesis/respiration Light dependent reaction - ATP & reduced NADP. Light independent - Carbohydrate. Respiration - glycolysis = glucose into private. Link reaction produces acetylcoenzyme A. Krebs cycle produces reduced coenzymes, co2 and ATP . Electron transport chain produces ATP and water. Respiratory quotient


    Stimulus/response accelerator/vagus nerve affect heart rate. FSH, oestrogen and LH in menstrual cycle. Baby suckles, sending impulse to hypothalamus, prolactin & oxytocin, producing milk. nervous reflex =saliva, conditioned reflexes = smell of food causes secretion of gastric juice. Hormones Food in stomach causes release of gastrin - gastric juice. Food in small intestine causes secretion of CCKPZ (pancreatic enzymes and bile) and secretin (alkaline fluid). Action potential brought about stimulus opening voltage-sensitive Na+ gates. Disturbs adjacent membrane causing its Na+ ions to open as well. Synapses neurotransmitter causes AP in postsynaptic membrane. Pacinian corpuscle transduces mechanical pressure into nerve impulse. Rod and cone cells. Sliding filament theory during depolarisation, Ca2+ ions enter sarcoplasm, bind to complex and so reveal binding site. ATPase activity on myosin head occurs, cross-bridge forms and “power-stroke”. COLD - vasoconstriction, hair raising, shivering and increased metabolic rate. HEAT- vasodilation, increased sweating, decreased metabolic rate.


    Negative feedback Control of CO2 detected by chemoreceptors (medulla). à breathing rate. Blood cholesterol controlled by liver - changes how much it makes according to levels. Islets of Langerhans in pancreas control glucose conc. Hypothalamus detects temperature of blood flowing through it, initiates response via autonomic nervous system.


    Variation Independent assortment and chiasmata in meiosis 1 produce variation. Normal distribution = same mean/mode/median. GENE mutation - base deletion or substitution. Polygenic inheritance. SPECIES defined by being similar to each other but different to other species, and being able to produce fertile offspring.

    Natural selection stabilising e.g. birth mass. Directional e.g. warfarin resistance in rats. Disruptive selection e.g. peppered/black morphs.
 
 
 
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