Turn on thread page Beta
    Offline

    1
    ReputationRep:
    (Original post by sillysal)
    if the grade boundaries are low, does that mean they wont be worth as much UMS marks for example, say usually an A is 80%, 80/100 raw marks is 120 UMS marks, but if the grade boundary for an A is 60%, this will only be worth 90 UMS marks ??
    No, the UMS boundaries don't change, only the raw ones
    Offline

    0
    ReputationRep:
    (Original post by sillysal)
    if the grade boundaries are low, does that mean they wont be worth as much UMS marks for example, say usually an A is 80%, 80/100 raw marks is 120 UMS marks, but if the grade boundary for an A is 60%, this will only be worth 90 UMS marks ??
    No I think the value for each mark is scaled up. So if its like 60 for an A it'l still be worth 120 ums I think. At least thats what my teacher told me a while back
    Offline

    8
    ReputationRep:
    (Original post by heartskippedabeat)
    No, the UMS boundaries don't change, only the raw ones
    phew! thanks
    Offline

    8
    ReputationRep:
    (Original post by atman7)
    No I think the value for each mark is scaled up. So if its like 60 for an A it'l still be worth 120 ums I think. At least thats what my teacher told me a while back
    thanks, got a bit worried then :P
    Offline

    1
    ReputationRep:
    (Original post by sillysal)
    phew! thanks
    No probs
    Offline

    0
    ReputationRep:
    (Original post by atman7)
    basically each unit except the 4th one. Also includes every old spec question with mark scheme for each unit
    cool thanks im going to look at these now instead of the text book
    Offline

    0
    ReputationRep:
    Another question..what do we actually need to know about drd4 receptors? i cant make sense of the book
    Offline

    1
    ReputationRep:
    What percent of the textbook is relevant with regard to the specification?
    Offline

    0
    ReputationRep:
    (Original post by rebeccalouise_92)
    cool thanks im going to look at these now instead of the text book
    no problem oh a bit i forgot to add a about cDNA in the Genetic Engineering Insulin part so just note that in somewhere
    Offline

    0
    ReputationRep:
    Do you think the griffith experiment on mice will come up in a question to do with bacteria and genetic engineering?

    I always ignore the green bits in the textbook but it seems like quite an important experiment
    Offline

    0
    ReputationRep:
    I found a little animation on genome sequencing if it helps anyone:
    http://www.pbs.org/wgbh/nova/genome/media/sequence.swf

    Does anyone know why batch culture is best for the production of secondary metabolites?
    Offline

    0
    ReputationRep:
    (Original post by emma237)
    Do you think the griffith experiment on mice will come up in a question to do with bacteria and genetic engineering?

    I always ignore the green bits in the textbook but it seems like quite an important experiment
    i think its an example of bacterial conjugation so it is possible if you know what bacterial conjugation is then you'll probably be alright with it. Although if it does come up can't see it being many marks max of 2/3 I think.
    Offline

    0
    ReputationRep:
    (Original post by emma237)
    Do you think the griffith experiment on mice will come up in a question to do with bacteria and genetic engineering?

    I always ignore the green bits in the textbook but it seems like quite an important experiment
    i think genetic engineering will definitely come up, not sure exactly about the mice part. i usually ignore the green however im thinking it is a good idea to look over it! especially as the dairy cows were tested in jan11? or jnue 10 , can't remember, but this section was in the text book in a green box!
    Offline

    0
    ReputationRep:
    (Original post by wrench22)
    I found a little animation on genome sequencing if it helps anyone:
    http://www.pbs.org/wgbh/nova/genome/media/sequence.swf

    Does anyone know why batch culture is best for the production of secondary metabolites?

    secondary metabolites are usually antibiotics. the bacteria only produces antibiotics under competition...during batch culture teh nutrients will start to run out and so bacteria are competing to have certain nutrients.. so they produce antibiotics to kill off the other bacteria, so they get the nutrients. wheras in continuous they continually have a supply so only primary metabolites will grow! really messy explanation but hope u understand.
    Offline

    1
    ReputationRep:
    (Original post by wrench22)
    I found a little animation on genome sequencing if it helps anyone:
    http://www.pbs.org/wgbh/nova/genome/media/sequence.swf

    Does anyone know why batch culture is best for the production of secondary metabolites?
    Secondary metabolites are produced in the stationary phase, but in continuous culture the microorganisms are kept in the log phase and so they never reach the stationary period and don't produce secondary metabolites
    Offline

    0
    ReputationRep:
    (Original post by rebeccalouise_92)
    secondary metabolites are usually antibiotics. the bacteria only produces antibiotics under competition...during batch culture teh nutrients will start to run out and so bacteria are competing to have certain nutrients.. so they produce antibiotics to kill off the other bacteria, so they get the nutrients. wheras in continuous they continually have a supply so only primary metabolites will grow! really messy explanation but hope u understand.
    Won't the antibiotics kill all the bacteria seeing as they're genetically identical?
    Offline

    0
    ReputationRep:
    (Original post by wrench22)
    Won't the antibiotics kill all the bacteria seeing as they're genetically identical?
    i think they produce it under competition and those that are genetically identical will not be affected as they produce it also :s im not really sure ... but as the person above said it is during stationary phase that this occurs, not log phase so that is a difference.
    Offline

    0
    ReputationRep:
    (Original post by wrench22)
    I found a little animation on genome sequencing if it helps anyone:
    http://www.pbs.org/wgbh/nova/genome/media/sequence.swf

    Does anyone know why batch culture is best for the production of secondary metabolites?
    Too many **** explanations so here you are;

    In a batch culture, the nutrients are only added once at the beginning of the process and hence go through the stationary phase (in a growth curve) where secondary metabolites are produced. These metabolites (antibiotics) help reduce competition from other microorganisms for the decreased level of nutrients.

    In a continuous one, however, nutrients are continually added, hence more primary metabolites are produced as part of growth (i.e. it doesn't enter the stationary phase where nutrients are limited and instead is always at the exponential phase- if space in unlimited). The products can be taken at any intervals and there would always be a lot of primary metabolites.

    Edit: Cheers for the negs
    Offline

    0
    ReputationRep:
    (Original post by jakehartley123)
    Too many **** explanations so here you are;

    In a batch culture, the nutrients are only added once at the beginning of the process and hence go through the stationary phase (in a growth curve) where secondary metabolites are produced. These metabolites (antibiotics) help reduce competition from other microorganisms for the decreased level of nutrients.

    In a continuous one, however, nutrients are continually added, hence more primary metabolites are produced as part of growth (i.e. it doesn't enter the stationary phase where nutrients are limited and instead is always at the exponential phase- if space in unlimited). The products can be taken at any intervals and there would always be a lot of primary metabolites.
    safe
    Offline

    0
    ReputationRep:
    (Original post by merrmerr)
    Tbh i think the jan 11 paper was better than the june!! I did much better in that! Though i hated the question on PCR i got 1/9 for that essay :P haha

    Can someone summarise DRD4 stuff coz im not actually sure which parts we are meant to know?
    Also are people doing the stretch n challenge stuff??
    The dopamine hypothesis of schizophrenia says that increased dopamine levels lead to schizophrenia. Alleles of genes for dopamine receptors and enzymes which break down dopamine have been linked to schizophrenia
    Studies have shown the DRD4 gene to be linked to ADHD. The condition is not fully genetic, or environmental.
    Individuals with ADHD or schizophrenia can show abnormal behavior, or excessive gambling. Therefore, genotype affects human behaviour
 
 
 
Poll
A-level students - how do you feel about your results?

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.