Turn on thread page Beta

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

Announcements
  • View Poll Results: Are you resitting this unit?
    YES!
    54.92%
    NO!
    45.08%

    Offline

    0
    ReputationRep:
    (Original post by RoadRunner)
    How's everyone feeling about it now ?
    scared. whether i get an A or not completely depends on the paper. fingers crossed it's easy and the ums is insanely low and the guy who marks my paper is generous.

    how're you feeling?
    Offline

    0
    ReputationRep:
    Even though I know that I know most of the topics I am still feeling awful about the exam! I just panic as soon as I see the questions and make stupid mistakes. Exam questions it is for the rest of the evening...
    Offline

    0
    ReputationRep:
    (Original post by nicollade)
    Even though I know that I know most of the topics I am still feeling awful about the exam! I just panic as soon as I see the questions and make stupid mistakes. Exam questions it is for the rest of the evening...
    couldnt agree more!
    Offline

    0
    ReputationRep:
    people are saying the 5 mark questions are gonna be about immunity and stuff! i am soo crap on that..our teacher is rubbish for that topic!
    soo could anyone help me by giving me the main aspects of what could be included??? pleaseee thanks!
    Offline

    7
    ReputationRep:
    (Original post by DoaaK)
    scared. whether i get an A or not completely depends on the paper. fingers crossed it's easy and the ums is insanely low and the guy who marks my paper is generous.

    how're you feeling?
    Ahhhh im sure you will be okay though just take your time and think ! Nervous very nervous, just never know if i have put like the right stupid simple facts/obvious things or not ..... :/
    Offline

    7
    ReputationRep:
    (Original post by Tinkle)
    people are saying the 5 mark questions are gonna be about immunity and stuff! i am soo crap on that..our teacher is rubbish for that topic!
    soo could anyone help me by giving me the main aspects of what could be included??? pleaseee thanks!
    Possibly ask you describe the humoral response / cell mediated response etc as in the steps involved, t cells, macrophages porferins etc

    Or how they differ?
    Offline

    2
    ReputationRep:
    just waiting for tomorrow.....will anyone post the paper we do tomorrow? im gnna post chem1 with solutions next week =) (no arsey)

    the posts on this thread literally doubled today....imagine tomorrow -_-
    Offline

    13
    ReputationRep:
    Can anyone give me a rough outline on what the paper could be about tomorrow?
    Offline

    0
    ReputationRep:
    I would expect them to not have a lengthy question for the 5 marker as it is usually only a sentence long. It could be something like "Describe how B cells respond when they are stimulated by antigens". (This is from the AQA text book and is only a 4 mark question but should give you the general idea of the detail required). The mark scheme says:

    B cells divide by mitosis/form a clone,
    Develop into plasma cells,
    Produce/ secrete antibody,
    Form memory cells.

    I hope that helps with the kind of detail needed
    Good luck tomorrow!
    Offline

    7
    ReputationRep:
    Yeah i find the best way to answer is think about it in simple little steps for the 5 marks, describe each step with a simple sentence, as thats how it is in the mark scheme

    Yeah good luck everyone
    Offline

    0
    ReputationRep:
    (Original post by Wick3d)
    Can anyone give me a rough outline on what the paper could be about tomorrow?
    Im thinking immunity T cells B cells, probably something about the structure of epithelial cells ( lysosomes, ER, Nucleus). Cholera and digestion
    Offline

    0
    ReputationRep:
    oo thank yyou!! makes soo much more sense now! i feel less stressed! i have two exams tomorrow! ahh kill me now!
    Offline

    13
    ReputationRep:
    Does anyone know how to do question 4.c.iii) and 5.b) from the Jan 11 paper? Thanks!
    Offline

    2
    ReputationRep:
    Do you think they could ever give a 5 marker on the steps of ultracentrifugation?
    Offline

    6
    ReputationRep:
    Maybe at a stretch, if you include describing why you place the thing you're ultracentrifuging into isotonic and ice cold solutions etc.
    Offline

    2
    ReputationRep:
    (Original post by Sparkly-Star)
    Does anyone know how to do question 4.c.ii) and 5.a) from the Jan 11 paper? Thanks!
    4cii? you've just gotta know that triglycerides have 3 fatty acids and 1 glycerol

    5a! wow aqa are so mean! I wrote sodium chloride but they wanted you to write water or sodium chloride solution?!
    Offline

    6
    ReputationRep:
    Immunity is not that hard. You just need to apply it a lot.

    So the main things we need to know are phagocytosis, Cell Mediated Immunity, and Humoral Immunity.

    Phagocytosis goes like this.
    1) The phagocyte is attracted to the pathogen via chemoattractants and it moves along their conc. gradient towards the pathogen.
    2) The phagocyte 1st attatches to the pathogen and then englufs the pathogen and creates a phagosome
    3) Vesicles in the phagocyte attatch to the phagosome and secrete lytic enzymes whihc break down the pathogen
    4) All soluble products of the breakdown are then absorbed by the Phagocyte.

    Cell Mediated immunity goes something like this.
    1) A pathogen invades a host and is taken in by a phagocyte.
    2) The phagocyte then presents antigens from the pathogen on it's surface.
    3) It is then specifically recognised by a Receptor protein on a T Cell
    4) This results in induced mitosis and differentiation of the T cell into :
    a) T Killer cells=kill the infected cells
    b) T helper cell which help in Humorla immunity
    c) Memory Cells to prevent recurring infection of the SAME pathogen
    d) Stimulates phagocytosis


    Humoral Immunity is like this
    1)A pathogen invades a host.
    2) The antigens of the invading pathogen are then taken up by B cells.
    3) They are then presented on their surface
    4) T helper cells then help process the antigen and result in induced mitosis
    5) PLasma cells are created which secrete antibodies to destroy the pathogen (This is the primary response)
    6) Memory cells are made which prevent recurring infection.

    In terms of defnitions
    Antigen : Any substance which enters a host organism and is specifically recognised as a non self
    Antibody: These are immunoglobulins with specifically shaped recognition regions
    Vaccination: A substance which contains antigens which stimulates the production of antibodies

    Antibodies are specific as they have an exact sequence of amino acids which results in an exact 3D shape which is complementary to only 1 type of antigen

    Monoclonal antibodies are essentially clones of 1b cell and so they all have the exact same receptor proteins on their surface and so can only recognise 1 type of antigen

    2 Types of immunity
    Active and Passive

    Active is split into natural and artificial,
    Active natural= Becoming immunocompetent to a specific disease by actually suffering it
    Active Artificial = Vaccination

    Passive is split into natural and artificial:
    Passive Natural: Obtaining antibodies from breastmilk as a baby
    Passive Artificial: Antiserum

    I hope this helps some of you. I think this is all of it and this is most of what I know off the top of my head. If I have missed anything out I'm sure someone will point it out

    Good Luck
    Offline

    0
    ReputationRep:
    (Original post by Sparkly-Star)
    Does anyone know how to do question 4.c.ii) and 5.a) from the Jan 11 paper? Thanks!
    and 4ciii and 5.b too, can you do those two?

    Just doing that paper now
    Offline

    13
    ReputationRep:
    (Original post by EffKayy)
    4cii? you've just gotta know that triglycerides have 3 fatty acids and 1 glycerol

    5a! wow aqa are so mean! I wrote sodium chloride but they wanted you to write water or sodium chloride solution?!
    (Original post by Tericon)
    and 4ciii and 5.b too, can you do those two?

    Just doing that paper now
    Oh no I meant 4.c.iii) and 5.b) too not the ones I mentioned lol. I know how to do those. :p:
    Offline

    0
    ReputationRep:
    (Original post by Tericon)
    and 4ciii and 5.b too, can you do those two?

    Just doing that paper now
    It's 9. Look at the diagram above, count how many R groups there are 8, and plus the X bond. 9

    --

    20cm3 = 1 mol

    So

    4cm3 = 0.2 mol (divide it by 5)

    As there is 4cm3 of NaCl, there must be 16cm3 of water, to make it up ot 20 cm3.
 
 
 
Poll
Which accompaniment is best?

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.