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AQA BIOL1 Biology Unit 1 Exam - 16th May 2011 watch

  • View Poll Results: Are you resitting this unit?
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    (Original post by EffKayy)
    Define disease?!? omg panic panic, i don't know how to define it? When a pathogen invades and causes harm?

    Add ethanol, shake it, water? Cloudy-white?
    Disease - a condition with a specfic cause, it can be a physical/mental disorder, when the body functions in a non-normal or less effiecent manner. Can include symptoms.

    Yup
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    i think i'll just learn elastic tissue which controls air flow

    will this be correct ?
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    (Original post by liviaaa)
    It moves from roothair cell, to xylem by osmosis. Up the xylem by cohesion-tension, cappilarity or root pressure. NOT active transport - that requires ATP, and the xylem is made from dead cells.

    --

    Anyway this is AQA unit 1, not OCR unit 2.
    Yeah listen to this person. I can do from roots to stem but nothing above it. Hate xylem and phloem. Dunno what they even are? Organs?
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    (Original post by hash007)
    do you mean ions move in by active transport? I'm pretty sure water moves in by osmosis.
    Meh hate ocr, should have done aqa.
    this is unit 1. Please do not confuse us and leaveeeeeeeeeeee.
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    (Original post by liviaaa)
    Disease - a condition with a specfic cause, it can be a physical/mental disorder, when the body functions in a non-normal or less effiecent manner. Can include symptoms.

    Yup
    Oh okay!
    Do you think they can ask us to give the mechanism of breathing? inspiration and expiration, for 5marks?
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    (Original post by emmaaa65)
    describe how cholera is transmitted and how it causes disease. use your knowledge of water potential in your answer (5 marks)
    Cholera is transmitted through polluted drinking water. Causes carrier proteins to be permenatly open so chloride ions escape into lumen, lowering water potential, water moves down water potential by osmosis, causing diahrea.
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    (Original post by EffKayy)
    Oh okay!
    Do you think they can ask us to give the mechanism of breathing? inspiration and expiration, for 5marks?
    Yup possibly.
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    (Original post by liviaaa)
    Some random Q:

    -Define disease

    -What's the biochemical test for a lipid?

    - What is the role of the nucleus?
    Disease is any malfunction of the body which results in poorer health

    2cm^3 of sample is added to a test tube same with ethanol to dissolve the sample add water and shake if its cloudylipid is present.

    Role of the nucleus is to act as the control centre of the cell through the production of mrna and hence protein synthesis
    Retain the genetic information of the cell in the form of DnA and Chromsoomes
    Manufactures ribosonal rna and ribosomes
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    (Original post by emmaaa65)
    describe how cholera is transmitted and how it causes disease. use your knowledge of water potential in your answer (5 marks)
    Fave topic but Unit 2?

    Chlorea is transmitted in dirty water. Can survive for a few days in the air. Generally a week. It causes the Cl- channel proteins to open so the Cl ions enter the lumen which lower the water potential causing water to enter the the lumen which gives water faeces and diarrheoa and flatulance. Treated with ORS which consists of Na+ glucose and water so that the Na+ and glucose enter the body cells lowering water potential there so water leaves the lumen and enters the body cell.
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    (Original post by Ramin Gorji)
    Disease is any malfunction of the body which results in poorer health

    2cm^3 of sample is added to a test tube same with ethanol to dissolve the sample add water and shake if its cloudylipid is present.

    Role of the nucleus is to act as the control centre of the cell through the production of mrna and hence protein synthesis
    Retain the genetic information of the cell in the form of DnA and Chromsoomes
    Manufactures ribosonal rna and ribosomes
    Yeah I think that's all right.
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    (Original post by ??????????????????)
    Fave topic but Unit 2?

    Chlorea is transmitted in dirty water. Can survive for a few days in the air. Generally a week. It causes the Cl- channel proteins to open so the Cl ions enter the lumen which lower the water potential causing water to enter the the lumen which gives water faeces and diarrheoa and flatulance. Treated with ORS which consists of Na+ glucose and water so that the Na+ and glucose enter the body cells lowering water potential there so water leaves the lumen and enters the body cell.
    Chloera is unit 1?
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    (Original post by liviaaa)
    Chloera is unit 1?
    I'm not sure now.
    Yup CGP says 1.3
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    (Original post by emmaaa65)
    describe how cholera is transmitted and how it causes disease. use your knowledge of water potential in your answer (5 marks)
    Cholera is a prokaryotic bacteria which causes severe diarrhea in infected individuals. It is spread by poor sanitation and poor sewage systems, and poor hygiene such as not washing hands with anti-bacterial soap. It's method of action is that is binds to carbohydrate receptors on the epithelial cells of the small intestine due to the shape being complementary to receptors on the cholera bacterium surface. This causes chloride protein channels to open and chloride ions flows out into the lumen of the intestine by diffusion. This causes a decrease in the water potential of the lumen to a level lower than that in the epithelial cells and blood, so water flows out of the blood, across the epithelial cells into the lumen of the intestine by osmosis. This causes severe and extreme diarrhea which can result in serious dehydration which can result in death if untreated by oral rehydration therapy.
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    (Original post by ??????????????????)
    Fave topic but Unit 2?

    Chlorea is transmitted in dirty water. Can survive for a few days in the air. Generally a week. It causes the Cl- channel proteins to open so the Cl ions enter the lumen which lower the water potential causing water to enter the the lumen which gives water faeces and diarrheoa and flatulance. Treated with ORS which consists of Na+ glucose and water so that the Na+ and glucose enter the body cells lowering water potential there so water leaves the lumen and enters the body cell.
    yeahh
    i wrote

    Cholera is transmitted through water that is contaminated with the bacterium. This can be spread by preparing/eating food with hands that have faecal contamination with the bacterium. The cholera bacterium produces a toxin that binds to chloride ion protein carriers on the epithelial cells of the small intestine. This changes the shape of the protein carrier and chloride ions are released into the lumen of the small intestine. This lowers the water potential of the small intestine causing water to travel by osmosis from epithelial cells, blood and surrounding tissue which have a relatively high water potential compared to that of the lumen. This loss of water from the blood and tissue causes dehydration in the individual and diarrhoea.



    i always forget to write about ORS and all that stuff
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    advantages and limitations of tem and sem anyone????
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    describe the risk factors involved with coronary heart diesease and include in your answer how smoking can cause a myocardial infarction (5marks)
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    (Original post by emmaaa65)
    yeahh
    i wrote

    Cholera is transmitted through water that is contaminated with the bacterium. This can be spread by preparing/eating food with hands that have faecal contamination with the bacterium. The cholera bacterium produces a toxin that binds to chloride ion protein carriers on the epithelial cells of the small intestine. This changes the shape of the protein carrier and chloride ions are released into the lumen of the small intestine. This lowers the water potential of the small intestine causing water to travel by osmosis from epithelial cells, blood and surrounding tissue which have a relatively high water potential compared to that of the lumen. This loss of water from the blood and tissue causes dehydration in the individual and diarrhoea.



    i always forget to write about ORS and all that stuff
    Don't need to include ORS cos the question didn't ask for it. Just included it for the sake of it so in case anybody wasn't sure about ORS.
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    (Original post by gunit123)
    advantages and limitations of tem and sem anyone????
    advantages of tem
    *small objects can be seen, also internal details
    *higher resolution
    *small wavelength of electrons
    disadvantage
    *staining process has to occur, and yet it is still black and white
    *2d??
    *artefacts may occur from prep.
    *has to be in a vacuum
    *living specimens cant be tested
    *specimen has to be extremely thin

    SEM ADVANTAGE - specimen doesnt have to be thin.
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    (Original post by emmaaa65)
    describe the risk factors involved with coronary heart diesease and include in your answer how smoking can cause a myocardial infarction (5marks)
    Risk factors:
    -Genetic
    -Smoking
    -Lack of exercise
    -High blood pressure


    Smoking causes tar build up in the arteries so they are smaller. This increases pressure. If there are arethroma's in the body, they can become dislodged from the pressure and end up clotting the Coronary arteries which reduced/stop blood flow to the heart so less oxygen. This causes the muscle tissues to die as they have no oxygen to respire with so no ATP produced to contract muscle to the heart tissue dies leading to a MI.
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    (Original post by gunit123)
    advantages and limitations of tem and sem anyone????
    Overall advantages of electron microscopes:

    - Both types have much higher resolution(and thus magnification) compared to optical microscopes due to the (de broglie) wavelength of electrons being much shorter than that of visible light.

    Overall disadvantages:

    -Both types cannot produce a colour image.
    -Both types require a vacuum, so living specimens cannot be observed.

    TEM:

    Advantages:

    -Higher resolution than SEM microscopes
    -Allows density of specimen to be evaluated.

    Disadvantages:

    -Requires very thin specimens.
    -Complex staining and preparation process required which can result in artefacts.
    -Produces only a 2d image.

    SEM:

    Advantages:

    -Can produce a 3d image of the surface of the specimen
    -Specimen does not need to be prepared and sliced first

    Disadvantages:

    -Lower resolution than TEM
 
 
 
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