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    Industrial scale fermenters

    Conditions:

    Temperature
    - high - enzyme is denatured
    - low - growth rate slows down

    Nutrients
    - Carbon, Nitrogen, Vitamins and Minerals

    Oxygen concentration
    - Lack of oxygen causes anaerobic respiration to occr which produces unwanted products
    - growth rate slows down

    pH
    - Change in pH - reduces enzyme activity
    - reduces growth rate



    Growing conditions are maximised to increase the yield of the products required.


    Batch and Continuous culture

    Batch culture
    - Closed fermenter
    - Nutrients added the start
    - Products collected at the end
    - Exponential phase is short
    e.g. Pencillin, yoghurt.

    Advantages
    - Easy to control conditions
    - Produces secondary metabolites

    Disadvantages
    - Large vessels needed
    - Waste products build up

    Continuous culture
    - Open fermenter
    - Nutrients added continuously
    - Products collected continuously
    - Microorganism is kept in the exponential phase
    - e.g. Quorn, human insulin produced by GM yeast.

    Advantages
    - Greater productivity
    - Do not need to empty, sterilise fermenter

    Disadvantages
    - Difficult to control conditions
    - Does not produce secondary metabolites


    Asepsis
    - The absense of unwanted organisms - contaminants
    Unwanted organisms:
    - Compete with wanted organisms for resources such as nutrients and space, which reduces the yield.
    - Kill the wanted organism
    - Produce waste products.


    Industrial enzymes

    - Specificity
    - Temperature - enzymes usually work well at low temperatures. Enzymes from thermophilic bacteria work well at high temperatures.
    - Enzymes used rather whole organisms
    - Downstream processing - products from fermenter undergo filtration, purification and packaging.

    Enzymes become immobilised by being:
    - Adsorbed/bonded on to a insoluble matrix e.g. cellulose, collagen
    - Held in a gel lattice, such as silica gel - entrapment
    - Held in a partially permeable membrane e.g. cellophane
    - Held in microcapsules of alginate.

    Advantages:
    - Easy to remove
    - Can be reused
    - More stable in changing temperature and pH.
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    is this right about nitrogen cycle:


    nitrogen gas is present atmosphere.plants can not use this form of nitrogen so bacteria convert gaseous nitrogen into nitrogen compounds.
    For example, in nitrogen fixation, free living bacteria in soil or nitrogen fixing bacteria called rhizobium found in root nodules convert nitrogen gas into ammonia which can be taken in by plants. Therefore, the provide plants with a more useable form of nitrogen.

    when plants and animals die, decomposes convert the nitrogen compunds into ammonium compounds which are released into the soil ie nh4+. Also by urine etc.
    these ammonium compounds are converted into nitrogen compounds which can be used plants by nitrification. For example, nitrfying bacteria called xxxx convert ammonium ions into nitrites which are converted

    cant be bothered to finish
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    (Original post by TX22)
    is this right about nitrogen cycle:


    nitrogen gas is present atmosphere.plants can not use this form of nitrogen so bacteria convert gaseous nitrogen into nitrogen compounds.
    For example, in nitrogen fixation, free living bacteria in soil or nitrogen fixing bacteria called rhizobium found in root nodules convert nitrogen gas into ammonia which can be taken in by plants. Therefore, the provide plants with a more useable form of nitrogen.

    when plants and animals die, decomposes convert the nitrogen compunds into ammonium compounds which are released into the soil ie nh4+. Also by urine etc.
    these ammonium compounds are converted into nitrogen compounds which can be used plants by nitrification. For example, nitrfying bacteria called xxxx convert ammonium ions into nitrites which are converted

    cant be bothered to finish
    Yes you are right but i tink we need to know more about it in detail such as the conversion of Nitrogen into nh3 and nh4- done by various different bacteria. Some which are anaerobic also about denitryfying bacteria long with the process of assimilation.Oh also that weird name given to one of the process during nitrogen cycle Nosomopata? something i don't remember
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    Can someone please summarise the nitrogen cycle in simple words, mentioning just what is required to know for the exam. Each time I look into a new book mentions something new, now Im getting confused.
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    Hey, has anyone got notes for Module 2-Biotechnology and Gene Technologies??

    I really hate this module
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    (Original post by thekooks)
    Hey, has anyone got notes for Module 2-Biotechnology and Gene Technologies??

    I really hate this module
    You and me both the first couple of chapters are okay. Someone posted their notes a couple of pages ago, i still havent finished my notes on this =/ meh

    Btw really helpful animation on muscle contraction:
    http://www.wiley.com/college/pratt/0.../actin_myosin/
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    hi can sum1 plz explain 2 me da whole of spread 2.2 9 please cheers
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    (Original post by CertifiedAngel)
    You and me both the first couple of chapters are okay. Someone posted their notes a couple of pages ago, i still havent finished my notes on this =/ meh

    Btw really helpful animation on muscle contraction:
    http://www.wiley.com/college/pratt/0.../actin_myosin/
    Yeah, I've got notes until the 8th double spread but the rest is so hard.
    Gonna make notes on Module 4 tonight aswell...so thanks for the muscle contraction animation
    Got a mock coming up soon
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    I think they were my notes.. . I can repost if anyone likes.
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    (Original post by skatealexia)
    I think they were my notes.. . I can repost if anyone likes.
    Yes please
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    yes please post the notes, it would be really helpful
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    (Original post by emmz619)
    hi can sum1 plz explain 2 me da whole of spread 2.2 9 please cheers
    Which is? can you be bit more specific please.
    Thanks
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    (Original post by TX22)
    yes please post the notes, it would be really helpful
    Notes for which module again ? =)
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    (Original post by uer23)
    Can someone please summarise the nitrogen cycle in simple words, mentioning just what is required to know for the exam. Each time I look into a new book mentions something new, now Im getting confused.
    Ill use this as a chance to use my revision

    Outlining the 4 processes:

    Firstly, Nitrogen Fixation:
    This takes Nitrogen gas, N2, Rhizobium bacteria which are found in the root nodules of legumes convert the N2 into a form plants can use, ammonia ions/ammonia (and then animals take in by eating plants). This can also be caused by lightning and car engines .

    2nd, Ammonification by Decomposers :
    This is where decomposers break down dead or waste material and produce ammonium compounds. This includes break down of animal waste/faeces which contains proteins, theyre broken down to amino acids.

    3rd, Nitrification:
    Ammonium compounds are converted firstly to Nitrite ions by Nitrosomanas bacteria.
    Nitrite ions are converted to Nitrate ions by Nitrobacter (a bacteria).
    The bacteria's are called Nitrifying bacteria.

    4th, Denitrification:
    Pseudomonas/Denitrifying bacteria (not sure if you need to know the name, its not in this guide im using) convert Nitrate ions back to Nitrogen gas, N2.

    Although i had to check to make sure i was correct so i think this should cover it.

    this picture is very helpful in summarising this simply:


    As for the Notes emmz was talking bout, the spread is DNA Manipulation - Separating and Probing, outlining electrophoresis and DNA Probes (I havent even done this in class yet lol).
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    (Original post by Falcon91)
    Ill use this as a chance to use my revision

    Outlining the 4 processes:

    Firstly, Nitrogen Fixation:
    This takes Nitrogen gas, N2, Rhizobium bacteria which are found in the root nodules of legumes convert the N2 into a form plants can use, ammonia ions/ammonia (and then animals take in by eating plants). This can also be caused by lightning and car engines .

    2nd, Ammonification by Decomposers :
    This is where decomposers break down dead or waste material and produce ammonium compounds. This includes break down of animal waste/faeces which contains proteins, theyre broken down to amino acids.

    3rd, Nitrification:
    Ammonium compounds are converted firstly to Nitrite ions by Nitrosomanas bacteria.
    Nitrite ions are converted to Nitrate ions by Nitrobacter (a bacteria).

    4th, Denitrification:
    Pseudomonas/Denitrifying bacteria (not sure if you need to know the name, its not in this guide im using) convert Nitrate ions back to Nitrogen gas, N2.

    Although i had to check to make sure i was correct so i think this should cover it.
    Excellent that refreshed some stuff oh also remember that the enzyme is called nitrogenase and that it needs h20+ atp+ anaerobic respiration to convert N into NH4.
    One more thing: When plants germinates it produces protein called lectin which binds onto the polysaccahride on the cell surface membrane of the bacteria.In a sense bacteria over-takes the roots causes stimulation of cells hence => nodule formed.
    The relationship which rhizobium and plant share is called mutualism.
    =}
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    Genomes and gene sequencing

    Sequencing a genome

    1) A sample of the genome is mapped by using a marker - identifies which part the genome has came from, existing knowledge is also used.
    2) The sample is sheared into small sections around 100,000 bp.
    3) This is then placed into BACs (Bacterial Artificial Chromosomes) which is then transferred into E.coli cells.
    4) Cells are then grown in a culture - forms clone libraries.
    5) DNA is then extracted from the cells
    6) Restriction enzymes cut the DNA into small fragments
    7) Fragments are separated by electrophorisis
    8) Fragments are then sequenced by an automated process
    9) Computer programme used to compare overlapping regions and to reassemble the whole BACs segment sequence.


    Comparitive gene mapping

    - to identify a gene for a protein to see its importance to a living process
    - comparing genes to see evolutionary relationships
    - modelling the effects of changes to genes
    - DNA is analysed - to see if were more likely to get a specific disease


    Electrophorisis

    Used to seperate DNA fragments based on their size.

    1) Restriction enzymes cut the DNA into small fragments
    2) Fragments placed into wells in the negative electrode end of agarose gel
    3) Placed into a tank containing buffer solution at the appropriate pH
    4) Direct electric current passes through the gel
    5) DNA fragments are negatively charged so move towards the positive electrode (anode)
    6) The shorter the DNA fragment, the further it travels
    7) Dye is used to stain the DNA.



    Southern blotting
    - nylon sheet is placed over the gel and covered with paper towels
    - DNA fragments are transferred onto the sheet which is then analysed.
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    (Original post by student92)
    Genomes and gene sequencing

    Sequencing a genome

    1) A sample of the genome is mapped by using a marker - identifies which part the genome has came from, existing knowledge is also used.
    2) The sample is sheared into small sections around 100,000 bp.
    3) This is then placed into BACs (Bacterial Artificial Chromosomes) which is then transferred into E.coli cells.
    4) Cells are then grown in a culture - forms clone libraries.
    5) DNA is then extracted from the cells
    6) Restriction enzymes cut the DNA into small fragments
    7) Fragments are separated by electrophorisis
    8) Fragments are then sequenced by an automated process
    9) Computer programme used to compare overlapping regions and to reassemble the whole BACs segment sequence.


    Comparitive gene mapping

    - to identify a gene for a protein to see its importance to a living process
    - comparing genes to see evolutionary relationships
    - modelling the effects of changes to genes
    - DNA is analysed - to see if were more likely to get a specific disease


    Electrophorisis

    Used to seperate DNA fragments based on their size.

    1) Restriction enzymes cut the DNA into small fragments
    2) Fragments placed into wells in the negative electrode end of agarose gel
    3) Placed into a tank containing buffer solution at the appropriate pH
    4) Direct electric current passes through the gel
    5) DNA fragments are negatively charged so move towards the positive electrode (anode)
    6) The shorter the DNA fragment, the further it travels
    7) Dye is used to stain the DNA.



    Southern blotting
    - nylon sheet is placed over the gel and covered with paper towels
    - DNA fragments are transferred onto the sheet which is then analysed.
    Excellent summary! thanks
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    DNA probes

    Complementary to DNA fragment being investigated.
    Labelled in 2 ways:
    - Radioactive marker - 32 P - locates specific sequences
    - Blue, fluorescent dye - makes the DNA visible.

    - Any fragment with a complementary base sequence is annealed
    - used to identify and locate specific DNA sequences.


    PCR - Polymerase Chain Reaction

    Requires DNA to have:
    - Antiparallel backbone strands
    - 3' end and a 5' end
    - grows only at 3' end
    - base pairing rule A-T, C-G.

    Primer - short, single strand length of DNA - binds to complementary regions of the DNA near its ends.

    PCR - One cycle

    1) DNA sample is mixed with DNA polymerase and DNA nucleotides
    2) Denaturation at 95° for 60 seconds - H-bonds between the complementary nucleotide bases is broken
    3) Annealing at 55° for 45 seconds - Primer binds to any complementary regions of the DNA
    4) Extension at 72° for 2 minutes - Primer is extended by using Taq polymerase, by adding free nucleotides (dNTPs)
    5) Forms 2 strands of double stranded DNA
    6) Cycle repeats itself and number of strands increases exponentially.

    2^n n = number of times the cycle goes around.


    Gene sequencing

    1) Double stranded DNA is denatured to form single strands
    2) Primer is annealed at the 3' end
    3) DNA polymerase makes copies of the single stranded DNA by adding free nucleotides (according to the base pairing rules A-T, C-G)
    4) Modified nucleotide is added > DNA polymerase is thrown off > reaction is stopped at the template strand
    5) Fragments from newly synthesised DNA are produced, have different lengths
    6) Fragments differ in length by one nucleotide
    7) Each nucleotide is labelled with a colour
    8) Mixed, so separated by electrophoresis
    9) Pass through laser > reads coloured sequence > base sequence identified.


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    Does anybody have any question packs on the whole genetics module of this exam? so all the genetic crosses and all that? i really really really hate it!! i dont know what I am going to do, I'm desperate.
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    hii! could anyone explain epistasis 2 me pleease! i dont get it at all.. i understand that it when it masks 1 gene or works in a complemetary way with another gene. but i dont undersatnd the examples. thanks!!!
 
 
 
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