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    (Unfinished)
    These are by no means, entirely correct, they are just brief indications of what I wrote and a few points from other people.
    I personally thought it was a hard paper.

    Q1)
    Name the pigment at the reaction centre (1)
    • chlorophyll a

    Name an accessory pigment (1)
    • carotene/xanthophyll/chlorophyll b (POSSIBLY carotenoids)

    Purpose of accessory pigments (1)
    • absorb a range of wavelengths not well absorbed by chlorophyll and pass on that energy
    • maybe protect chlorphyll from very intense light

    Name of compound formed (1)
    • adenosine triphosphate (ATP)

    Enzyme that fixes CO2 in calvin cycle (1)
    • rubisco

    stable intermediate formed (1)
    • Glycerate-3-phosphate

    Compound regenerated (1)
    • Ribulose bisphosphate (RuBP)

    Polysaccharides that can be formed (1)
    • Cellulose and starch/(amylose/amlyopectin)


    Q2)
    Why is it a transducer? (1)
    • converts one form of energy to another (pressure stimulus converted to electrical energy of nerve impulse)


    Suggest how membrane made more permeable to Na+ (1)

    • Gate of sodium ion channel forced open/ deformation by pressure

    What is the all or nothing law? (1)
    • action potentials do not vary in size, either happens or doesn't (if reaches threshold potential (-50mV))

    How intensity of stimulus signalled to brain? (2)
    • frequency of action potentials indicates strength
    • greater frequency = more intense
      OR
      All action potentials same magnitude but stronger stimuli produce more action potentials

    Why do the impulses generated stop? (1)
    • acclimitisation/runs out of vesicles/fatigued

    Role of synapses (3)
    • Ensure one direction only
    • Intergration (convergence/divergence)
    • Summation (temporal/spatial)
    • memory and conscious thought
    • Filter out low level signals

    Q3)
    Condition tested for (1)
    • diabetes mellitus

    Why was he fasting? (1)
    • Needs to have a high blood glucose concentration so effect of insulin can be seen

    Calculate % increase (2)
    • 18.6%

    Explain when a glucagon injection is needed (1)
    • blood glucose concentration low/hypoglacaemia

    Hb complex thing why not useful after 8-12 weeks? (2)
    • red blood cells broken down and recycled in liver
    • therefore less Hb complex thing than there should be


    Explain why blood glucose was higher in test than over 8 week period (1)
    • nervous before taking exam = increased blood glucose levels/had just been exercising

    Describe role of glucagon (5)
    • detected by alpha cell receptors
    • glucaon secreted binds to complementary receptor cells in liver plasma membrane
    • gluconeogenesis (making glucose from fats/amino acids)
    • glycogenolysis(breaking down glycogen to glucose)
    • more fatty acids used in respiration
    • role of adenyl cylase/cyclic AMP
    • glucose leaves cells by faciliated diffusion
    • reference to inhibitory effect of hormone (stops insulin secretion)

    Explain why concentration of NAQ thing builds up (2)
    • the glutathione runs out
    • enzymes become saturated, cannot work quickly enough

    Name a neurotransmitter (1)
    • acetylcholine

    Where are the receptors located on the neurone and explain (2)
    • either pre or post synaptic membrane
    • stop secretion/stop binding

    Diagram of liver (5)
    • sinusoid
    • bile duct
    • hepatic portal vein (branch of)
    • hepatic artery (branch of)
    • hepatic vein (branch of)

    Liver cells that divide are called and how they do (1)
    • hepatocytes and mitosis

    Describe how respiration rate of cauliflower changes with temperature (2)
    • rate increases as temperature increases
    • figures quoted, trend (5 to 10 degrees rate doubles)

    What are the best conditions from table? (1)
    • low temperature (0 degrees)

    Which is the best fruit/vegetable to store and explain (3)
    • Onion as slowest rate of respiration at all temperatures
    • possibly potato at 0 degrees? unknown rate of respiration
    • really don't know what else to put for this one

    Which is the worst one and why? (1)
    • asparagus as has highest rate at all temperatures

    Why do parasites in blood respire anaerobically? (2)
    • oxygen tightly held to haemoglobin
    • no oxygen was the selection pressure for natural selection
    • can't kill host, so cannot use their oxygen
    • travel in deoxygenated areas of body (in veins) (possibly)

    Why is anaerobic respiration in animals reversible? (3 + QWC)
    • In mammals pyruvtae turned into lactate
    • lactate converted back to pyruvate in liver
    • in yeast CO2 released
    • Maybe doesn't have enzymes for conversion back?
      possibly lactate/ethanol dehydrogenase catalyse both directions, pryruvate carboxylase cannot

    Where is glucose reabsorbed? (1)
    • PCT ( I think the label was Q)

    Parts of the nephron in cortex (1)
    • All of them except the loop of henle and lower part of the collecting duct

    Where are podocytes found? (1)
    • Renal capsule label

    how long loop of henle helps desert mouse (2)
    • greater salt concentration in medulla
    • more water reabsorbed by osmosis from collecting duct
    • maybe ref. to mechanism, impermeable ascending walls, greater countercurrent mechanism

    Substance tested for in urine (1)
    • anabolic steroids
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    The one you can't remember at the end is about podocytes

    Thanks for this btw, everyone asks for but nobody bothers to make the unofficial mark schemes!!!
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    Wasn't it asparagus not celery?
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    (Original post by Mule)
    Q1)
    Name the pigment at the reaction centre (1)
    • chlorophyll a

    Name an accessory pigment (1)
    • carotene/xanthophyll

    Purpose of accessory pigments (1)
    • absorb wavelength not well absorbed by chlorophyll and pass on that energy

    Name of compound formed (1)
    • adenosine triphosphate (ATP)

    Enzyme that fixes CO2 in calvin cycle (1)
    • rubisco

    stable intermediate formed (1)
    • Glycerate-3-phosphate

    Compound regenerated (1)
    • Ribulose bisphosphate (RuBP)

    Polysaccharides that can be formed (1)
    • Cellulose and starch


    Q2)
    Why is it a transducer? (1)
    • converts one form of energy to another (pressure stimulus converted to electrical energy of nerve impulse)


    Suggest how membrane made more permeable to Na+ (1)

    • Gate of sodium ion channel forced open/ deformation by pressure

    What is the all or nothing law? (1)
    • action potentials do not vary in size, either happens or doesn't (if reaches threshold potential (-50mV))

    How intensity of stimulus signaleld to brain? (2)
    • frequency of action potentials indicates strength
    • greater frequency = more intense

    Why do the impulses generated stop? (1)
    • acclimitisation/runs out of vesicles/fatigued

    Role of synapses (3)
    • Ensure one direction only
    • Intergration (convergence/divergence)
    • Summation (temporal/spatial)
    • memory and conscious thought
    • Filter out low level signals

    Q3)
    Condition tested for (1)
    • diabetes mellitus

    Why was he fasting? (1)
    • Needs to have a high blood glucose concentration so effect of insulin can be seen

    Calculate % increase (2)
    • 16.8%

    Explain when a glucagon injection is needed (1)
    • blood glucose concentration low/hypoglacaemia

    Hb complex thing why not useful after 8-12 weeks? (2)
    • red blood cells broken down and recycled in liver
    • therefore less Hb complex thing than there should be

    Describe role of glucagon (5)
    • detected by alpha cell receptors
    • glucaon secreted binds to complementary cells in liver
    • gluconeogenesis
    • glycogenolysis
    • more fatty acids used in respiration
    • role of adenyl cylase/cyclic AMP

    Name a neurotransmitter (1))
    • acetylcholine

    Where are the receptors located on the neurone and explain ( can't remember if 2 or 1)
    • either pre or post synaptic membrane
    • stop secretion/stop binding

    Diagram of liver (5)
    • sinusoid
    • bile duct
    • hepatic portal vein (branch of)
    • hepatic artery (branch of)
    • hepatic vein (branch of)

    Liver cells that divide are called and how they do (1)
    • hepatocytes and mitosis

    Describe how respiration rate of cauliflower changes with temperature (2)
    • rate increases as temperature increases
    • figures quoted, trend (5 to 10 degrees rate doubles)

    What are the best conditions from table? (1)
    • low temperature (0 degrees)

    Which is the best fruit/vegetable to store and explain (3)
    • Onion as slowest rate of respiration at all temperatures
    • don't know what else

    Which is the worst one and why? (1)
    • celery as has highest rate at all temperatures

    Why do parasites in blood respire anaerobically? (2)
    • oxygen tightly held to haemoglobin
    • no oxygen was the selection pressure for natural selection

    Why is anaerobic respiration in animals reversible? (3 + QWC)
    • In mammals pyruvtae turned into lactate
    • lactate converted back to pyruvate in liver
    • in yeast CO2 released
    • Maybe doesn't have enzymes for conversion back?

    Where is glucose reabsorbed? (1)
    • PCT

    Parts of the nephron in cortex (1)
    • All of them except the loop of henle and lower collecting duct

    ( one more question I can't remember) (1)
    how long loop of henle helps desert mouse (2)
    • greater salt concentration in medulla
    • more water reabsorbed by osmosis from collecting duct

    Substance tested for in urine (1)
    • anabolic steroids
    The one you cant remember was "which feature contains Podocytes?" It was the Bowmans Capsule.

    Also, the hardest one to keep was Asparagus, NOT celery.
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    Am I the only one who thought the transduction question shouldn't have been asked? That's physics!
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    It was Asparagus
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    I'm sure the answer for the percentage increase was 18.60%.
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    (Original post by basmaay)
    I'm sure the answer for the percentage increase was 18.60%.
    Yeah... I got 18.6%
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    Using this i only got 34 ish out of 60... I'm aiming for an A fml
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    (Original post by Bisphosphate)
    Am I the only one who thought the transduction question shouldn't have been asked? That's physics!
    It's in the heinman book, but I don't think many people read that bit, lol I do physics and physics wouldn't of helped me with that.

    Its just ocr being awkward, again.
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    (Original post by Bisphosphate)
    Am I the only one who thought the transduction question shouldn't have been asked? That's physics!

    "outline the roles of sensory receptors in
    mammals in converting different forms of
    energy into nerve impulses"

    That's from the specification, nothing specifically about transducers but my book covered it.
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    (Original post by 2102)
    Using this i only got 34 ish out of 60... I'm aiming for an A fml
    I've probably missed a lot of marks, these are just off the top of my head of some things I wrote, that's why I want people to contribute.
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    45 If I'm lucky, which isn't an A. yay.
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    Is chlorophyll B classed as an accessory pigment?
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    (Original post by AliBachir)
    45 If I'm lucky, which isn't an A. yay.
    Again don't make an accurate prediction based on this rough mark scheme yet.
    Also 45 could well be an A.
    A* boundaries for unit 4:
    June 10 - 47
    Jan 11 - 51
    June 11 - 45
    Jan 12 - 51
    June 12 - 49
    Jan 13 - 49
    June 13 - 50

    And I personally thought this was a bad paper
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    (Original post by RadishWadish)
    Is chlorophyll B classed as an accessory pigment?
    yes
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    (Original post by RadishWadish)
    Is chlorophyll B classed as an accessory pigment?
    I think it is, i'm not certain though.
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    Can you say Type 2 Diabetes instead of Diabetes Mellitus?
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    Lool I know I sound like a **** but I was actually scared that I got an A/B as apposed to an A*
    Could someone add the asparagus and onion question please...I put that the onion would be the most stable and that asparagus the least stable
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    (Original post by Mule)
    Again don't make an accurate prediction based on this rough mark scheme yet.
    Also 45 could well be an A.
    A* boundaries for unit 4:
    June 10 - 47
    Jan 11 - 51
    June 11 - 45
    Jan 12 - 51
    June 12 - 49
    Jan 13 - 49
    June 13 - 50

    And I personally thought this was a bad paper

    Thanks alot for that. I think you did a pretty good job on the mark scheme but I disagree with one of your answers. For the parasite question, I wrote that not all blood is oxygenated such as that found in the veins. This means the parasite cannot respire aerobically until it reaches the lungs again and so has adapted to respire anaerobically. I hope that's right at least ...
 
 
 
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