Hey! Sign in to get help with your study questionsNew here? Join for free to post

Edexcel Biology (Unofficial) B2 Mark Scheme.

Announcements Posted on
Why bother with a post grad? Are they even worth it? Have your say! 26-10-2016

    (Original post by Usk40)
    For the DNA section, Does nayone know the answer about the base/codon question. I got 210 but i'm not sure if thats right?
    I did 630 times 3 not divide. So I got 1890

    Posted from TSR Mobile

    (Original post by keepyourapology)
    How did that exam go? Will be posting a mark scheme based on answers soon!

    Special thanks to niichola!
    Question 1 (Bacterial/Yeast Cell) :
    Part (a):
    (yeast cell)
    • has a nucleus (1)
    • does not have a flagellum(1)
    • does not have a plasmid(1)
    • has a vacuole(1)
    (bacterial cell)
    • has chromosomal DNA /circular DNA (1)
    • has a capsule (1)
    • has a slime coat (1)
    • does not have mitochondria (1)
    Mitochondria. (1)
    Question about how anaerobic respiration breaks down to form alcohol and carbon dioxide. Compare anaerobic and aerobic respiration of a yeast cell.
    Part (?):
    The values for the table go from 300 -> 400 -> 200. This shows that the Enzyme activity is reduced below or above the optimum temperature/pH.
    This applies to all enzymes, hence most of their graphs have an upside down U-shape.
    So the value for the sucrose/lactose (can't remember which) will not increase as the values go from 28 -> 35 ->
    It will rather decrease to around (28 -7) = 21. It could be from around 17-21, hence it is that is the correct answer.
    (thanks to TheMasterofLife!)

    Question 2 (Digestion):
    Part (a):
    Disadvantages of using the tube as a model : No villi
    Part (c):
    The amylase in the saliva will break down the starch present in the bread to form sucrose.

    Fossils Question :
    Part(a) :D
    Part (b):
    Human Intervention
    Loss of habitat
    Climate Change
    Predators (correlate to increase in group B&C)
    • The mammals have a humerus;
    • an ulna
    • wrist bones
    • and 5 fingers/digits. There is more to write, but that should be enough. The other answers are:
    • a radius
    • The wrist bones are called carpals
    DNA Extraction:
    Part(b):Break up proteins in cell membrane.
    Differences between mitosis & meiosis:
    Haploid cells vs Diploid Cells (1)
    Genetically Varied vs Genetically Identical (1)
    4 Daughter Cells vs 2 Daughter Cells (1)

    Circulatory System:

    Part(a):Pulmonary Vein
    Part(b):De-oxygenated blood moves into the right atrium via the vena cava, moves to the right ventricle through the valves, and goes to the lungs via the pulmonary artery.
    Part(d):Six marker on how the narrowing of coronary arteries affect the functioning of the heart and surrounding body cells.
    • The narrower artery is on the left ventricle. By it being narrow, the muscles receive less oxygen and glucose, and will be worker weaker.
    • The ventricle will not be able to contract as strongly as before, causing less heart pressure
    • This will cause a weaker heart, and decrease the cardiac output
    • This means that the less blood will be going throughout the body, meaning more anaerobic respiration when exercising
    • There will be more lactic acid left over
    • There will be a longer excess post-exercise oxygen consumption (EPOC) (didn't actually write it, just realized it now)

    Light is no longer the limiting factor, and hence, increasing the amount of light intensity will not affect rate of reaction, as some other factor is in shorter supply and is controlling the rate.
    Part (d):
    Six marker on movement of water in a plant.
    Can you make an unofficial mark scheme for C2 please
Write a reply…


Submit reply


Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: June 15, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

What were/are your predicted grades?

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

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.