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    (Original post by Liverpool F.C.™)
    If you're looking for the OCR Chemistry thread, it's here.

    Past paper Questions are in my original post and also here.
    Woah thats one heavy set of questions:eek3: Does that include ALL the questions from them papers? cheers again dude
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    (Original post by Falcon91)
    The book has a small bit on this so most of the listed stuff below is from the CGP page on it

    Describe how timber can be harvested sustainably (oh yes, the joy) soon enough we'll probs cover the syllabus asking these questions
    Hey! Lets get back to it. I can do anything now, except galapagos bit, and the dopamine receptors stuff. So ask away!

    As to the timber one...

    Timber can be harvested sustainably for both small scale timber production and large scale timber production.

    Small scale Timber production:
    Coppicing is used, this is where the tree is cut close to the ground to encourage new shoot growth. Several shoots will grow from the cut surface and these will mature into stems of relatively narrow diameter. These can be harvested, and the process will repeat itself as part of a coppicing cycle.
    In order to provide a continous supply of wood, rotational coppicing is carried out, this is where the woodland is split up into several sections, and then each section is cut in turn each year to allow for the other ones to grow again.
    Within the woodland, some trees are left to grow, without coppicing and they are known as standards, this enables for larger pieces of wood to be harvested.

    In areas where there are lots of deer, pollarding can be carried out, thi is similar to coppicing, but the tree is cut higher up, so that the deer cannot feed on the emerging shoots.

    Rotational coppicing also allows for biodiversity to be maintained. As the woodland doesn't continue to grow and block out light for other species.

    Large scale timber production:

    This works on the basis that if a tree is able to supply more wood, then less trees will need to be felled. Ideally, in order to maintain biodiverity the woodland would need to be left for 50-100 years, and then the largest trees can be felled, causing minimal loss to biodiversity, but this is not an economical process.
    So: For every tree that is harvested, one is planted. They aim to maintain the forest/woodland biodiversity. They grow only trees that will grow well to produce good timber, the trees are separted by a condierable distance to avoid competition. Pesticides are also made use of.

    ---> Decribe the similarities and differences between artifical and natural selection.
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    (Original post by ibysaiyan)
    Woah alrighty:
    Non-reproductive cloning: Here a non-reproducing (cell)genetic anomaly or fault within the cell is fixed.This is usually done by either having the correct allele version sprayed over liposome structure or over adenoviruses.Which is then inserted into the patient which is then exchanged within the lung cells as in CFTR although its effect are temporary lasting few weeks.
    Or perhaps by reversing the working of differentiated cells.
    As for reproductive cloning here a cell body is fused with eunucleated egg which goes onto form a zygote (after mitosis).
    :confused: Nope. This is gene therapy.

    Gene therapy is the use of various gene technologies in order to treat certain genetic disorders. This is your given example, of somatic gene therapy, where you insert a working copy of a gene into cells that hold dysfunctional copies of the gene, and as a result the working genes will be expressed to produce the correct polypeptides, so the symptoms will be mimised or not shown. The methods of transfer of the genes are not efficient processes, and in most cases liposomes are used, to enable for the gene to be passed through cell membrane barriers and into the cell, yet these are also ineffective.

    Reproductive and Non-reprodutive cloning are different issues to the above.

    Reproductive cloning is where you are making genetically identical copies of entire organisms. This is mainly for the benefit of humans, e.g by cloning high value animals, such as cows with a high milk yield. The two processes are embryo splitting and nuclear transfer using enucleated eggs.

    Non-reproductive cloning refers to the cloning of cells, tissue and organs in order to replace those that are damaged due to disease of accidents. So the direct use of embryonic stem cells from the indvidual in order to make cells/organs that are gentically identical to themselves, and for that reasons there is virtually no chance of rejection from the body, and no need to wait for donors.
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    has anyone got a good set of revision notes for module 3?

    i really dont want to go through the text book for it!!
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    (Original post by ViolinGirl)
    :confused: Nope. This is gene therapy.

    Gene therapy is the use of various gene technologies in order to treat certain genetic disorders. This is your given example, of somatic gene therapy, where you insert a working copy of a gene into cells that hold dysfunctional copies of the gene, and as a result the working genes will be expressed to produce the correct polypeptides, so the symptoms will be mimised or not shown. The methods of transfer of the genes are not efficient processes, and in most cases liposomes are used, to enable for the gene to be passed through cell membrane barriers and into the cell, yet these are also ineffective.

    Reproductive and Non-reprodutive cloning are different issues to the above.

    Reproductive cloning is where you are making genetically identical copies of entire organisms. This is mainly for the benefit of humans, e.g by cloning high value animals, such as cows with a high milk yield. The two processes are embryo splitting and nuclear transfer using enucleated eggs.

    Non-reproductive cloning refers to the cloning of cells, tissue and organs in order to replace those that are damaged due to disease of accidents. So the direct use of embryonic stem cells from the indvidual in order to make cells/organs that are gentically identical to themselves, and for that reasons there is virtually no chance of rejection from the body, and no need to wait for donors.
    The book I got doesn't say much but has elements of gene therapy along with cloning all together.
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    ibsaiyan, violingirl is right about what she said. i thought it was as you said but its not!

    what are you all doing to revise for synopticisim?
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    describe how the distribution and abundance of organisms can be measured, using line transects, belt transects, quadrats and point quadrats (HSW3);

    I'd rep if someone does this.
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    (Original post by ViolinGirl)
    :confused: Nope. This is gene therapy.

    Gene therapy is the use of various gene technologies in order to treat certain genetic disorders. This is your given example, of somatic gene therapy, where you insert a working copy of a gene into cells that hold dysfunctional copies of the gene, and as a result the working genes will be expressed to produce the correct polypeptides, so the symptoms will be mimised or not shown. The methods of transfer of the genes are not efficient processes, and in most cases liposomes are used, to enable for the gene to be passed through cell membrane barriers and into the cell, yet these are also ineffective.

    Reproductive and Non-reprodutive cloning are different issues to the above.

    Reproductive cloning is where you are making genetically identical copies of entire organisms. This is mainly for the benefit of humans, e.g by cloning high value animals, such as cows with a high milk yield. The two processes are embryo splitting and nuclear transfer using enucleated eggs.

    Non-reproductive cloning refers to the cloning of cells, tissue and organs in order to replace those that are damaged due to disease of accidents. So the direct use of embryonic stem cells from the indvidual in order to make cells/organs that are gentically identical to themselves, and for that reasons there is virtually no chance of rejection from the body, and no need to wait for donors.
    Thank u! Do u reckon that's all u'd need to say for spec bullet point :
    outline the differences between reproductive and non-reproductive cloning?

    Also, has anyone got good notes on lac operon? Or could ya explain itstep-wise please.

    Thanks!
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    Does anyone have good material or revision notes they used for the Immune system and disease etc?

    thats for the Biology OCR June AS exam.. pleaseeeeeee help me!!!!!!!!

    the people who re-sat this paper in Jan 2010 said it was mainly all Biochemistry.. so i have a feeling all the immune system and disease is to definitely come up..
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    I see that the old spec bio papers are split up under the following names:
    - "Growth, Development and Reproduction"
    - "Applications of Genetics"
    - "Microbiology and Biotechnology"
    - "Unifying Concepts..."
    - "Central Concepts"
    - "Environmental Biology"
    - "Physiology and Behavior"

    Any suggestions on which of the papers will be the most relevant to what we are doing now? I guess the "genetics", "micro and biotech", "environmental" and "physiology and behaviour" papers will be the most applicable, but any opinions on the other ones?
    ..and yes, I'm lazy and am trying to save myself of having to look through all of them for relevant questions :P, so any suggestions would really really x100 help
    Thank you!
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    (Original post by redfanatic)
    ibsaiyan, violingirl is right about what she said. i thought it was as you said but its not!

    what are you all doing to revise for synopticisim?
    Absolutely nothing. No need really. Whats the worst they could throw back from old units?!:p:
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    (Original post by zoop)
    Thank u! Do u reckon that's all u'd need to say for spec bullet point :
    outline the differences between reproductive and non-reproductive cloning?

    Also, has anyone got good notes on lac operon? Or could ya explain itstep-wise please.

    Thanks!
    I don't really make notes. But yes lets explain the lovely lac operon!

    Ok, bacteria are able to vary the rates of synthesis of certain enzymes, called inducible enzymes, depending if certain substrates are present in their environment.
    The lac operon is a section of DNA on the bacterium DNA, it consists of structural genes, operator region and promotor region. The regulatory gene is also involved in the process but it is not part of the lac operon. The operator and promotor regions are genes, but they are not involved in the synthesis of polypeptides. Structual genes code for enzymes.

    E.coli can use both lactose and glucose as respiratory substrates. Glucose is its normal respiratory substrate. In the prescence of lactose, it will increase the rates of synthesis of both beta galactosidase and lactose permease.

    Lactose acts as an inducer molecule. The regulator gene is continually expressed to produce a repressor protein, this has 2 binding sites, one to the lactose molecule and one to the operator region.

    When no lactose is present, the repressor protein binds to the operator region and blocks off the promotor region, so RNA polymerase cannot bind there and genes cannot be transcribed. Lactose will bind to other site of repressor protein, and cause it to change shape. It can no longer bind to operator region, so promotor region is no longer blocked. RNA polymerase can bind and genes can be transcribed. !
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    (Original post by HELPME-ology)
    Does anyone have good material or revision notes they used for the Immune system and disease etc?

    thats for the Biology OCR June AS exam.. pleaseeeeeee help me!!!!!!!!

    the people who re-sat this paper in Jan 2010 said it was mainly all Biochemistry.. so i have a feeling all the immune system and disease is to definitely come up..
    I remember the immune system quite well, but I don't want to explain unless I get something wrong. AS was waaaaay back.
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    (Original post by Sakujo)
    describe how the distribution and abundance of organisms can be measured, using line transects, belt transects, quadrats and point quadrats (HSW3);

    I'd rep if someone does this.
    I promise to get back to you on this in the next hour!
    Just too lazy to type in now.
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    Oh, and does anyone have the Heinnmann exam cafe CD? If anyone does, could you possibly please send me a copy of the answers to the exam questions at the end of each chapter of unit 5?

    Will rep
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    (Original post by smflesh)
    Oh, and does anyone have the Heinnmann exam cafe CD? If anyone does, could you possibly please send me a copy of the answers to the exam questions at the end of each chapter of unit 5?

    Will rep
    Pirate.
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    (Original post by Sakujo)
    Pirate.
    Arr.
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    :s so worried about this exam xxx
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    (Original post by smflesh)
    Oh, and does anyone have the Heinnmann exam cafe CD? If anyone does, could you possibly please send me a copy of the answers to the exam questions at the end of each chapthttp://www.thestudentroom.co.uk/er of unit 5?

    Will rep
    Here
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  1. File Type: pdf RES12_bio_book_answers.pdf (272.8 KB, 202 views)
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    (Original post by Sakujo)
    describe how the distribution and abundance of organisms can be measured, using line transects, belt transects, quadrats and point quadrats (HSW3);

    I'd rep if someone does this.
    Using a Quadrat

    • Randomly position the quadrats across the habitat, using random numbers to plot coordinates for each one
    • Count the number of organsims in each quadrat when it is randomly placed
    • Take samples at regular distances across the habitat so you sample each part of the habitat to an extent


    Measures both the abundance and distribution, however the percentage cover cannot be estimated as it is hard to count small species such as grass and moss

    Using a Point Quadrat

    • Stand point quadrat firmly on ground
    • Lower each needle downwards and record the species that the tip touches
    • Number of species the needle touches is proportional to the percentage cover of that species


    Transect

    Useful to measure the gradual changes in vegetation across a habitat
    Line

    At regular intervals make a note of which species is touching the tape
    Only gives the abundance

    Belt

    At regular intervals, place a point quadrat next to the line(Interrupted Belt transect) or move a quadrat along the line after looking at each quadrat (continuous belt transect)

    Widens the line transect and the abundance as well as the presence and absencse of species can be measured (Distribution).


    I hope thats good enough to answer your question
 
 
 
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