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    (Original post by Tinkerbelle ♥)
    :yes: usually animals living in dry, hot climates. Like desert rats and camels and stuff

    we were given a practice question in class about why desert rats had a longer loop of Henle than we do.

    I was wondering - what is the point of creating this very negative water potential so water can leave the collecting duct by osmosis... when water reabsorbtion and permeability of the tubules can be controlled by release of ADH?

    Do the osmoreceptors that detect whether ADH needs to be release, work on how much water diffuses out of the collecting duct? I can't think of any other reason why both processes need to happen. Or am I being stupid!?
    only function of the loop is to produce maximum low water potential in the medulla, so that most of the water in the collecting duct be absorbed by the tissue fluid, again depends on the concentration of ADH.
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    (Original post by ibysaiyan)
    Ok here is this thing bugging me.Do we need to know each enzyme activated by cyclic AMP?> or just that this activates various enzymes which convert glycogen to glucose.
    thats kinda tricky, but to be on the safe side jus remember that it activates enzymes which activates glycogen phosphorylase which is the last enzyme that converts glycogen to glucose. (glycogenolysis).

    i dont think we do though because different protein hormones work in a similiar way activating cyclic amp then activating various different enzymes.
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    (Original post by ibysaiyan)
    Ok here is this thing bugging me.Do we need to know each enzyme activated by cyclic AMP?> or just that this activates various enzymes which convert glycogen to glucose.
    I would try to memorise all of the enzymes activated by cyclic AMP.

    So it's:

    1. G-protein splits and combines with the inactive enzyme Adenylyl Cyclase.

    2. This activates the enzyme which now converts ATP to cAMP.

    3. cAMP binds with another inactive enzyme called Protein Kinase activating it.

    4. Protein Kinase in turn activates another enzyme called Glycogen Phosphorlyase Kinase.

    6. Glycogen Phosphorlyase Kinase activates another enzyme called Glycogen Phosphorylase.

    7. Finally, Glycogen Phosphorylase catalyses the breakdown of glycogen in the liver cell and converts it to glucose.

    Best to remember in steps. Who knows, there may be a decent mark question on this.
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    (Original post by MadMaths)
    thats kinda tricky, but to be on the safe side jus remember that it activates enzymes which activates glycogen phosphorylase which is the last enzyme that converts glycogen to glucose. (glycogenolysis).

    i dont think we do though because different protein hormones work in a similiar way activating cyclic amp then activating various different enzymes.
    K , thanks
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    (Original post by ibysaiyan)
    Ok here is this thing bugging me.Do we need to know each enzyme activated by cyclic AMP?> or just that this activates various enzymes which convert glycogen to glucose.
    let me check.....you only need to understand that Adrenaline is the first messenger, which binds to its specific receptor on the cell cell surface membrane(shape complementary to adrenaline) and that this wil activate the enzyme adenyl cyclase(which is usually inactive in the inner membrane of the target cell) - once activated adenyl cyclase converts ATP to cAMP then cAMP(second messenger) activates other enzymes in the cell which have various effect on the cell metabolism, subsequently the whole body.g. increase heart rate, increase mental awareness, cause body hair to erect.
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    (Original post by InvoluntarySlacker)
    I would try to memorise all of the enzymes activated by cyclic AMP.

    So it's:

    1. G-protein splits and combines with the inactive enzyme Adenylyl Cyclase.

    2. This activates the enzyme which now converts ATP to cAMP.

    3. cAMP binds with another inactive enzyme called Protein Kinase activating it.

    4. Protein Kinase in turn activates another enzyme called Glycogen Phosphorlyase Kinase.

    6. Glycogen Phosphorlyase Kinase activates another enzyme called Glycogen Phosphorylase.

    7. Finally, Glycogen Phosphorylase catalyses the breakdown of glycogen in the liver cell and converts it to glucose.

    Best to remember in steps. Who knows, there may be a decent mark question on this.
    Oh that will take sometime :P, Thanks .
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    (Original post by Remarqable M)
    let me check.....you only need to understand that Adrenaline is the first messenger, which binds to its specific receptor on the cell cell surface membrane(shape complementary to adrenaline) and that this wil activate the enzyme adenyl cyclase(which is usually inactive in the inner membrane of the target cell) - once activated adenyl cyclase converts ATP to cAMP then cAMP(second messenger) activates other enzymes in the cell which have various effect on the cell's metabolism e.g. increase heart rate, increase mental awareness, cause body hair to erect.
    Yep, i thought the same.
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    Ok, thing to make a note of: difference between diabetes one and two :P, one is when the bodies own anti-bodies destroy beta-cells whereas Diabetes two happens when insulin stays in the blood for a prolonged time which inhibits the activity of the target cells for insulin.So insulin is being produced but its target cells don't respond to it.
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    (Original post by ibysaiyan)
    Ok, thing to make a note of: difference between diabetes one and two :P, one is when the bodies own anti-bodies destroy beta-cells whereas Diabetes two happens when insulin stays in the blood for a prolonged time which inhibits the activity of the target cells for insulin.So insulin is being produced but its target cells don't respond to it.
    Yep thats right everyone needs to keep asking questions this way will learn together much quicker

    note: type 2 diabetes is more to do with the decline of responsiveness of B-cells and their inability to perform with efficiency. Type 2 is more likely to be due to genetic variation and being of asian or afro-caribbean orgin
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    (Original post by Remarqable M)
    Yes thats right everyone needs to keep asking questions this way will learn together much quicker
    Agree :yes:
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    Hemodialysis
    In hemodialysis, the patient's blood is pumped through the blood compartment of a dialyzer, exposing it to a partially permeable membrane. The dialyzer is composed of thousands of tiny synthetic hollow fibers. The fiber wall acts as the semipermeable membrane. Blood flows through the fibers, dialysis solution flows around the outside the fibers, and water and wastes move between these two solutions. The cleansed blood is then returned via the circuit back to the body. Ultrafiltration occurs by increasing the hydrostatic pressure across the dialyzer membrane. This usually is done by applying a negative pressure to the dialysate compartment of the dialyzer. This pressure gradient causes water and dissolved solutes to move from blood to dialysate, and allows the removal of several litres of excess fluid during a typical 3 to 5 hour treatment. In the US, hemodialysis treatments are typically given in a dialysis center three times per week (due in the US to Medicare reimbursement rules); however, as of 2007 over 2,500 people in the US are dialyzing at home more frequently for various treatment lengths. Studies have demonstrated the clinical benefits of dialyzing 5 to 7 times a week, for 6 to 8 hours. These frequent long treatments are often done at home, while sleeping but home dialysis is a flexible modality and schedules can be changed day to day, week to week. In general, studies have shown that both increased treatment length and frequency are clinically beneficial.
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    (Original post by ibysaiyan)
    Ok, thing to make a note of: difference between diabetes one and two :P, one is when the bodies own anti-bodies destroy beta-cells whereas Diabetes two happens when insulin stays in the blood for a prolonged time which inhibits the activity of the target cells for insulin.So insulin is being produced but its target cells don't respond to it.
    Just to expand

    Type 1:
    beta cells don't produce insulin.
    After eating, blood glucose concentration rises and stays high - called hyperglycaemia. (When it's too low it's hypoglycaemia - both can lead to death and induce comas)
    Type 1 develops in children and young adults

    Type 2:
    Type 2 usually linked with obesity and aquired later in life.
    Occurs when beta cells don't produce enough insulin or because insulin receptors on cell membranes don't work properly so cells don't take up enough insulin.
    Blood glucose concentration remains higher than normal.
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    (Original post by Tinkerbelle ♥)
    Just to expand

    Type 1:
    beta cells don't produce insulin.
    After eating, blood glucose concentration rises and stays high - called hyperglycaemia. (When it's too low it's hypoglycaemia - both can lead to death and induce comas)
    Type 1 develops in children and young adults

    Type 2:
    Type 2 usually linked with obesity and aquired later in life.
    Occurs when beta cells don't produce enough insulin or because insulin receptors on cell membranes don't work properly so cells don't take up enough insulin.
    Blood glucose concentration remains higher than normal.
    Nicely laid out! in simple clear and short sentences is what usually gets people top marks.
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    Describe the structure of cholinergic Synapse.
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    there are two spellings for Adenyl cyclase and Adenylyl cyclase.....has anyone noticed and which is the right one?
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    (Original post by MadMaths)
    there are two spellings for Adenyl cyclase and Adenylyl cyclase.....has anyone noticed and which is the right one?
    Adenylyl cyclase :P
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    (Original post by MadMaths)
    there are two spellings for Adenyl cyclase and Adenylyl cyclase.....has anyone noticed and which is the right one?
    if I was you I'll go with the one thats easier to remember and in this case adenyl cyclase is easier to spell aswell
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    (Original post by Tinkerbelle ♥)
    ATP stands for Adenine TriPhosphate.. lol

    and ADP is Adenine DiPhosphate. Because it only has 2 phosphate groups.
    Like in respiration when one phosphate group had been broken off and we're left with ADP + Pi
    Thankies , Oh i knew it had 3 phosphate groups but didnt know it was made rom ribose sugar and adenine base lol silly me x

    (Original post by Remarqable M)
    aah don't lose your motivation your correct

    "The thing always happens that you really believe in; and the belief in a thing makes it happen."
    Frank Loyd Wright

    Thanks , im back! also picturing results day and uni - thats helping !

    Ill just type out my notes.

    I have notes on everything except control of heart rate and limiting factors on photosynthesis, so if anyone has those, would they type them out for me, that would be grand x
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    Peritoneal dialysis
    In peritoneal dialysis, a sterile solution containing minerals and glucose is run through a tube into the peritoneal cavity, the abdominal body cavity around the intestine, where the peritoneal membrane acts as a semipermeable membrane.The peritoneal membrane or peritoneum is a layer of tissue containing blood vessels that lines and surrounds the peritoneal, or abdominal, cavity and the internal abdominal organs (stomach, spleen, liver, and intestines). The dialysate is left there for a period of time to absorb waste products, and then it is drained out through the tube and discarded. This cycle or "exchange" is normally repeated 4-5 times during the day, (sometimes more often overnight with an automated system). Ultrafiltration occurs via osmosis; the dialysis solution used contains a high concentration of glucose, and the resulting osmotic pressure causes fluid to move from the blood into the dialysate. As a result, more fluid is drained than was instilled. Peritoneal dialysis is less efficient than hemodialysis, but because it is carried out for a longer period of time the net effect in terms of removal of waste products and of salt and water are similar to hemodialysis. Peritoneal dialysis is carried out at home by the patient. Although support is helpful, it is not essential. It does free patients from the routine of having to go to a dialysis clinic on a fixed schedule multiple times per week, and it can be done while travelling with a minimum of specialized equipment.
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    (Original post by MadMaths)
    there are two spellings for Adenyl cyclase and Adenylyl cyclase.....has anyone noticed and which is the right one?
    Is that in the OCR book with the brain on the front ?

    In the CPG book it says adenylate cyclase :confused:
 
 
 
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