Turn on thread page Beta
    Offline

    17
    ReputationRep:
    (Original post by haes)
    I remember reading the spec and it saying something about knowing darwin's and wallace's theory but like you said boring af so i didn't even look at it until now. because the spec is so vague i have no idea how much we're supposed to know :/
    Oh my.. I remember Darwin from GCSE but Wallace :confused:

    Waaait... I think I found the spec point. The evidence for the theory of evolution by natural selection? We kinda rushed through the last bit though.
    Offline

    1
    ReputationRep:
    (Original post by 4nonymous)
    The monomers dont have it in a 1:2 ratio. The monomer is glucose which is C6H12OH so the ratio is 6:13. When two react together yes water is formed between the two OH groups So you get C6H12-O-C6H12 so now the ratio is 1:2
    Glucose has the molecular formula C6H12O6

    Name:  Screen Shot 2016-05-25 at 20.17.37.png
Views: 181
Size:  78.0 KB
    Offline

    3
    ReputationRep:
    (Original post by aipomaniac)
    glucose has the molecular formula c6h12o6

    Name:  Screen Shot 2016-05-25 at 20.17.37.png
Views: 181
Size:  78.0 KB
    oops let me rethink that
    Offline

    15
    ReputationRep:
    (Original post by aipomaniac)
    Thank you! So what happens to hydroxyl group and hydrogen that combine to form water? However I am now extra confused as according to pubchem the molecular formula of cellulose is '(C6H10O5)n'I am sure it doesn't matter either way, but thank you for taking the time to explain it
    Omg, that's so true! I never actually thought of it confused now LOOOL, good catch!

    I think the question isn't asking about the bonds, but just in general whether they would have a 1:2 ratio, which they "do" (apparently, lol) because they're carbohydrates. Was this a multiple choice Q?
    Offline

    7
    ReputationRep:
    The problem with OCR is that their questions are too vague but their mark schemes too strict- I'm not getting the marks on the specimen paper even though my answers are completely valid. Why have they not given us a range of possible responses we can have to score marks like in the past papers??
    Please tell me in the actual thing tomorrow there'll be a range of answers we can give!!!
    Offline

    9
    ReputationRep:
    I don't think hardcore statistical tests questions will come up in breadth, right? That's more of depth ..?
    Offline

    3
    (Original post by haes)
    How much do you all know about the theory of evolution?
    I know the evidence for evolution (DNA, Cytochrome C, Fossil record, Domain system etc).

    And I know the observations of Darwin's theory. I know that the new species contain similar features from the extinct/older species placed in chronological order.
    I know that the theory links to natural selection.
    Offline

    1
    ReputationRep:
    (Original post by IRoranth)
    Omg, that's so true! I never actually thought of it confused now LOOOL, good catch!

    I think the question isn't asking about the bonds, but just in general whether they would have a 1:2 ratio, which they "do" (apparently, lol) because they're carbohydrates. Was this a multiple choice Q?
    Haha yep! I know I am probably stressing too much over one mark but in a test this HARD ever mark literally counts as gold dust!

    Also sorry for confusing you, but thank you so much for trying to explain it, I really appreciate it
    Offline

    1
    ReputationRep:
    (Original post by 4nonymous)
    oops let me rethink that
    Haha don't worry too much I am just stressing because the exam is tomorrow and I thought biological molecules were my strong point :')
    Offline

    3
    (Original post by plower)
    I don't think hardcore statistical tests questions will come up in breadth, right? That's more of depth ..?
    You'll never know, they'll just throw it in there But yeah, if there is a calculation question it will be worth 4 marks, which is quite high for a breadth paper. There is a possibility though, although this paper is more like 'limitations' and 'how experiments can be made fair, valid' etc as well as a basic information from vast majority of the topics.
    Offline

    3
    ReputationRep:
    (Original post by aipomaniac)
    Haha don't worry too much I am just stressing because the exam is tomorrow and I thought biological molecules were my strong point :'
    LOL YH SAME. Im trying to revise solidly now think Im over doing it though.
    Offline

    3
    (Original post by aipomaniac)
    hey guys, just doing some practice questions in preparation for tomorrow and one question asked if both glycogen and cellulose had carbon and hydrogen in a 1:2 ratio.

    I thought that they did not as it is a condensation reaction, so while the monomers have carbon and hydrogen in a 1:2 ratio the actual polymers would not as one molecule of water is lost with each glycosidic bond that is formed.

    However the mark scheme is saying that they do have carbon and hydrogen in a 1:2 ratio- would anyone be able to shed some light on this?
    They are both carbohydrates with a hexose sugar, where glycogen is alpha glucose and cellulose is beta glucose.
    Offline

    11
    ReputationRep:
    My thoughts on the exams I've done so far and revision techniques. http://www.thestudentroom.co.uk/show....php?t=4116471
    Offline

    2
    (Original post by James3000117)
    You need to know:

    the evidence for the theory of evolution bynatural selection:
    To include the contribution of Darwin and Wallace in formulating the theory of evolution by natural selection AND fossil, DNA (only genomic DNA at AS Level) and molecular evidence.

    Darwin's observations:
    1. Offspring are generally similar to their parents
    2. Organisms have the ability to produce large numbers of offspring
    3. Populations tend to remain fairly stable in size
    4. No two individuals are identical

    Deductions made and supporting observations:
    -Characteristics are passed on to the next generation (1)
    -There is a struggle for existence (2,4)
    -Individuals with beneficial characteristics are among the few who survive (2,3,4)

    Fossil evidence:
    -Fossils deeper in the ground are older than those near the surface
    -Comparing older fossils to newer ones allow us to see how the species evolved over time

    Molecular evidence:
    -Similarities between molecules common to two different species can be used to determine their evolutionary relationship
    -Eg. Similar base sequence in rRNA is commonly used, as is cytochrome C and haemoglobin.
    -The more similar the molecules are, the closer the evolutionary relationship

    Have some past paper questions and mark schemes
    Thank you so much!!!
    Offline

    7
    ReputationRep:
    (Original post by haes)
    Thank you so much!!!
    No problem, it's good revision to type it all out haha
    Offline

    10
    ReputationRep:
    I haven't even learnt classificationand some enymze stuff, but everything can't come up so I'll take my chances.
    Offline

    9
    ReputationRep:
    (Original post by oni176)
    You'll never know, they'll just throw it in there But yeah, if there is a calculation question it will be worth 4 marks, which is quite high for a breadth paper. There is a possibility though, although this paper is more like 'limitations' and 'how experiments can be made fair, valid' etc as well as a basic information from vast majority of the topics.
    That's quite true
    Offline

    9
    ReputationRep:
    (Original post by OddFuturez)
    I haven't even learnt classificationand some enymze stuff, but everything can't come up so I'll take my chances.
    😹😹 risky
    Offline

    8
    ReputationRep:
    Haven't learnt anything... What can i revise last minute... Its an afternoon exam ithinnk got enough tine
    Offline

    2
    ReputationRep:
    (Original post by Hmb28)
    Normally the grades go 80% A ,70% B , 60% C ,50% D and so on. Roughly need 42/70 on this paper to get a c grade
    Thats a shame haha....thanks.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: June 27, 2017
The home of Results and Clearing

1,062

people online now

1,567,000

students helped last year

University open days

  1. Sheffield Hallam University
    City Campus Undergraduate
    Tue, 21 Aug '18
  2. Bournemouth University
    Clearing Open Day Undergraduate
    Wed, 22 Aug '18
  3. University of Buckingham
    Postgraduate Open Evening Postgraduate
    Thu, 23 Aug '18
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.