Turn on thread page Beta
    Offline

    0
    ReputationRep:
    Hello, Can anyone put up their summarise notes for evidence and experiements on chemisomosis please, just in case that comes up thankyou
    Offline

    0
    ReputationRep:
    (Original post by Raj K)
    Rate of photosynthesis:
    could measure:
    - volume of oxygen produced
    - rate of uptake of co2
    - rate of increase in dry mass of plants

    Light intensity:
    - using a photosynthometer/audus microburette is set up, air-tight ensuring no air bubbles are present
    - gas given off by plant over time collects in the flared end of capillary tube
    - the syringe can be used to move the air bubble into the part of the capillary tube against the scale
    - distance moved by air bubble at each light intensity can be used to work out the volume and essentially the rate (by dividing the volume by the time left)
    - experiment should be repeated at the same light intensity and average values used
    - apparatus should be left to acclimatise for 5 mins
    - all other factors should be kept constant for eg in a water bath to keep the temperature constant

    hope it helped ???
    thankyou is this all we need to know for photosynthesis experiments or is there more?
    Offline

    1
    ReputationRep:
    (Original post by Fatima0065)
    Hello, Can anyone put up their summarise notes for evidence and experiements on chemisomosis please, just in case that comes up thankyou
    experimental evidence for theory of chemiosmosis:

    Researchers isolated mitochondria and treated them by placing them in a solution with a very low water potential

    - this meant that the outer membrane ruptured, releasing the contents of the intermembrane space.
    If they further treated these mitoblasts with a strong detergent, they could release the contents of the matrix.
    - this allowed them to identify the enzymes in the mitochondria, and to work out that the link reaction and Krebs cycle occurred in the matrix, whilst the enzymes for the electron transfer chain were embedded in the mitochondrial membrane.

    -electron transfer in mitoblasts did not produce ATP, so they concluded that the intermembrane space was also involved.

    ATP was also not made if the mushroom-shaped parts of the stalked particles were removed from the inner membrane of the intact mitochondria.
    ATP was also not made in the presence of oligomycin, an antibiotic which is now known to block the flow of protons through the ion channel part of ATP synthase.

    In the intact mitochondria
    - the potential difference across the membrane was -200mV, being more negative on the matrix side than on the intermembrane space side.
    - the pH of the intermembrane space was lower than that of the matrix
    Offline

    1
    ReputationRep:
    (Original post by Leah.94)
    thankyou is this all we need to know for photosynthesis experiments or is there more?
    i THINK that's it..i only have that in my notes..but take a look at past papers as they include experiments and check your answers with the mark scheme x
    Offline

    0
    ReputationRep:
    can someone please explain the treatments for kidney failure..i.e just heamodialysis and peritooneal dialysis.....also any potential questions they're likely to ask!?....im struggling to adjust this info in my head...im startin to panick for this exam now!!!
    Offline

    1
    ReputationRep:
    (Original post by aquarius00)
    can someone please explain the treatments for kidney failure..i.e just heamodialysis and peritooneal dialysis.....also any potential questions they're likely to ask!?....im struggling to adjust this info in my head...im startin to panick for this exam now!!!
    Dialysis:
    waste, excess fluid and salts are removed from the body by passing the blood over a dialysis membrane. This allows the exchange of substances between the blood and dialysis fluid, which has the same concentration of substances as blood plasma. Substances diffuse from both sides to create correct concentration of substances.

    Haemodialysis:
    Blood is passed through a machine that contains an ARTIFICIAL dialysis membrane. Heparin is used to avoid clotting of blood. Regular trips to hospital lasting several hours.

    Peritoneal dialysis:
    The body's own abdominal membrane is used as a filter..again several consecutive sessions at hospital

    they asked a question about this in one of the recent exam papers.

    Don't panic!!! (:
    Offline

    1
    ReputationRep:
    (Original post by Yasin-Ali)
    Someone help:
    The liver is responsible for the excretion of nitrogenous waste from the body right?
    Can someone correct/improve on my wording:
    Nitrogenous waste needs to be removed from the body because in large quantities it causes a toxic enviroment in the body. When there's a large quantity of amino acids in the body their amine groups are toxic so it's broken down by reaction with oxygen to produce keto acids(to be respired/stored as glycogen) and ammonia...blah blah.
    What other nitrogenous waste is there? I know about Uric acid too which is from the break down of dna right?
    Nitrogenous waste needs to be removed from the body because large quantities of it cause a toxic environment in the body.

    When there is a large quantity of amino acids in the body, excess amino acids can't be stored due to the amine group and instead of them being excreted, they are deaminated and a keto acid and ammonia is produced. Ammonia is toxic, and so the ornithine cycle occurs for the ammonia to be converted into urea. The urea is then excreted from the body.
    Offline

    0
    ReputationRep:
    Who wants to take a stab at these questions?
    Describe the main features of the light independent stage of photosynthesis. [8 marks]
    Describe the main features of the light dependent stage of photosynthesis. [8 marks]
    Describe the differences between cyclic and non-cyclic photophosphorylation. [3 marks]
    Explain how chloroplasts are adapted to their role. [4 marks]
    Offline

    0
    ReputationRep:
    (Original post by Maple)
    Who wants to take a stab at these questions?
    Describe the main features of the light independent stage of photosynthesis. [8 marks]
    I'll give it a shot ^^
    Firstly, carbon dioxide is absorbed through the stomata, and travels into the stroma of the chloroplast. Once in the stroma, carbon dioxide (CO2) combines with a 5 carbon compound Ribulose Bisphosphate (RuBP). RuBP is also said to be carboxylated (addition of CO2). The product of RuBP and CO2 combining, is an unstable 6-carbon molecule, so it is converted quickly into Glycerate Phosphate(GP) a 3 carbon compound, two molecules of GP are made for each CO2 and RuBP. GP is then phosphorylated (addition of ATP) and hydrogenated via the oxidation of reduced NADP. The product of this is another 3-carbon compound, triose phosphate (TP). 5/6 Molecules of TP can be phosphorylated to regenerate RuBP. TP can also be used to make glucose, hexose, fructose, disaccharides (from fructose and glucose), or can even be made into large macromolecules like starch and cellulose. GP can make amino acids, and fatty acids, and can combine with glycerol (made from TP) to produce lipids.

    I hope its right!
    Offline

    1
    ReputationRep:
    (Original post by Maple)
    Who wants to take a stab at these questions?
    marks]
    Explain how chloroplasts are adapted to their role. [4 marks]
    The chloroplast is a biconvex shape which provides a large surface area for light absorption. The high numbers of grana also provide a large surface area for the photosynthetic pigments such as chlorophyll. Other pigments such as carotenoids are present to absorb wavelengths of light that chlorophyll cannot absorb. The pigments are arranged into photosystems to harness light energy efficiently. DNA is present within the chloroplast to provide the proteins (such as enzymes) needed to catalyse photosynthetic reactions an example being the water splitting enzyme.

    Thats all I can think of.
    Offline

    0
    ReputationRep:
    (Original post by Maple)
    Who wants to take a stab at these questions?

    Describe the differences between cyclic and non-cyclic photophosphorylation. [3 marks]

    Cyclic phosphorylation produces only small amounts of ATP
    This ATP may be used in the light independent stage or to active transport potassium ions to change the water potenital so water flows in by osmosis causing the guard cells to swell and the stomata to open.
    No photolysis of water occurs
    No Reduced NADP is formed
    The electron lost from the chlorophyll molecule in cyclic photophosphorylation is accepted by an electron acceptor and then returns back to the chlorophyll molecule it was lost from.

    Have I missed anything? If so someone please do add
    Offline

    0
    ReputationRep:
    (Original post by atman7)
    Cyclic phosphorylation produces only small amounts of ATP
    This ATP may be used in the light independent stage or to active transport potassium ions to change the water potenital so water flows in by osmosis causing the guard cells to swell and the stomata to open.
    No photolysis of water occurs
    No Reduced NADP is formed
    The electron lost from the chlorophyll molecule in cyclic photophosphorylation is accepted by an electron acceptor and then returns back to the chlorophyll molecule it was lost from.

    Have I missed anything? If so someone please do add
    Great
    Just remember to put about cyclic only uses Photosystem I, and Non-cyclic uses photosystem I & II
    Offline

    0
    ReputationRep:
    (Original post by arcus)
    Great
    Just remember to put about cyclic only uses Photosystem I, and Non-cyclic uses photosystem I & II

    Opps I always forget the most obvious things Thanks for the reminder!
    • Thread Starter
    Offline

    1
    ReputationRep:
    can someone please explain the structure of the liver please???

    i just hate the liver
    Offline

    16
    argh so much to revise for this exam!

    I've spent all bloody day revising and I've only just finished the 1st topic!

    and now on to excretion which is like my worst one because we had a cover teacher for the entirety of it while our other teacher went on maternity leave. great.

    Offline

    0
    ReputationRep:
    (Original post by atman7)
    Opps I always forget the most obvious things Thanks for the reminder!
    No problem! But you would have got 3 marks anyway! :P
    Offline

    1
    ReputationRep:
    (Original post by undertaker1)
    can someone please explain the structure of the liver please???

    i just hate the liver
    these r from my notes not on top of my head! (:

    LIVER:
    hepatic arteries supply the liver with oxygenated blood from the heart, so the liver has a good blood supply of oxygen for respiration, providing plenty of energy

    the hepatic vein takes deoxygenated blood away from the liver - which rejoins the vena cava and normal circulation will proceed
    Bile duct is where the substance bile is secreted, which is carried to gall bladder where it is stored until it is required in the small intestines.
    The hepatic portal vein brings blood from small intestine, the blood is rich in products of digestion, and this means that any harmful substances ingested will be broken down quickly by the liver cells (hepatocytes).

    The liver is made up of lobules - each lobule has a central vein in the middle that connects to the hepatic vein. Every single lobule has branches of the hepatic artery, hepatic portal vein and bile duct.
    Hepatic artery and hepatic vein are connected to the central vein via capillaries called sinusoid.
    The blood flows past every hepatocyte via the sinusoid, this ensures that the harmful stuff are broken down quickly. Also the blood provides liver cells with oxygen.
    The central veins from all the lobules join up to form the hepatic vein.

    mate hope i helped!
    Offline

    0
    ReputationRep:
    (Original post by Leah.94)
    selective reabsoption:
    - sodium ions are removed from cells libing the PCT
    - sodium ions along with glucose or amino acids are actively transported into the cell by facilitated diffusion
    - as glucose and amino acid concentrations rise, they're now able to diffuse into tissue fluid. glucose or amino acids may also be actively removed from cell
    - substances diffuse into blood and are transported away
    - when glucose, amino acids and salts have been reabsorbed, the water potential of tubule fluid increases
    - water enters cells and is reabsorbed into blood by osmosis
    - endocytosis - larger molecules such as small proteins are reabsorbed into blood

    How cells in PCT are specialized:
    - cell surface membrane is folded to form microvilli which increases surface area for reabsorption
    - membrane contain cotransporter proteins to transport sodium ions, glucose or amino acids into cell by facilitated diffusion
    - opposite membrane contains sodium-potassium pumps to pump 3Na+ ions out for every 2K+ ions in
    cytoplasm has many mitochondria so lots of ATP

    hope this helps
    Thank you!

    I think I'm slowly but surely getting there!
    Offline

    0
    ReputationRep:
    (Original post by Maple)
    Who wants to take a stab at these questions?
    Describe the main features of the light independent stage of photosynthesis. [8 marks]
    1) Ribulose Bisphosphate (RuBP) reacts with CO2 with the help of enzyme rubisco to form an unstable 6 carbon compound
    2) unstable 6 carbon compound is broken down into 2 molecules of glycerate-3-phosphate (GP)
    3) each molecule of GP is reduced to triose phosphate (TP) using the hydrogen from NADPH and the energy from ATP

    5/6 molecules of TP are recycled by phosphorylation using ATP from light dependent stage, to make 3 molecules of RuBP
    - some GP can be converted to amino acids or fatty acids
    - pairs of TP can combine to form hexose sugars e.g. glucose, fructose, cellulose
    - some TP can be converted to glycerol which is converted to lipids

    is this right?
    Offline

    0
    ReputationRep:
    is the formation of ATP in photosynthesis pretty much the same as in chemiosmosis in animals?
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: November 26, 2012

University open days

  • Heriot-Watt University
    School of Textiles and Design Undergraduate
    Fri, 16 Nov '18
  • University of Roehampton
    All departments Undergraduate
    Sat, 17 Nov '18
  • Edge Hill University
    Faculty of Health and Social Care Undergraduate
    Sat, 17 Nov '18
Poll
Have you ever experienced bullying?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.