B2 Biology Unofficial Mark Scheme - 9th June 2017 - AQA GCSE

Thanks for making this! I think I got around 56. Any estimates to what UMS this would be? (I need to be high in case tripple went as bad as I think!)

Possibly add in small explanations for the small marker questions? I've seen tons of people claim it's a 20% increase.
16 to 20
1/4 of 16 is 4
16 + 4 = 20
1/4 = 25% So if 100% is considered to be 16, 100+25% = 125 % of original = 20
Therefore 25% increase

For question 2 I did transect sampling not random sampling, would I still get the marks?

For question 2 I did transect sampling not random sampling, would I still get the marks?

For question 2 I did transect sampling not random sampling, would I still get the marks?

For question 2 I did transect sampling not random sampling, would I still get the marks?

Maybe if you still included all the other points but you may have needed to reference random sampling I stated both ....just in case 🙂

For question 2 I did transect sampling not random sampling, would I still get the marks?

So i made this from other people's posts combined, if parts aren't correct please let me know
If there's parts missing tell me haha

1)
[Where are epithelial cells found?]
Epithelial cells can be found in the skin or inside the body as lining around organs (There is more for this)

[Labelling the parts of the epithelial cell]
-Cell membrane
-Cytoplasm
[What are ribosomes for?]
-Protein synthesis

[What is diffusion]
-Diffusion is the movement of particles from a high concentration to a low concentration to achieve equilibrium

2) [6 marker on the quadrat]
~Random sampling by standing and throwing
~Sample different areas
~Count twice to remove human error
~Repeat investigation to be more valid
~Count number of plants in quadrat and test the pH using the measure
~Repeat in different areas of pH
- etc.

3) [Glucose sports drinks]
[Why are placebos important?]
To provide a control to compare it to and so thst the cyclists don't know which they have so they don't act differently thinking that they are under the influence
[Evaluate the scientists' conclusion - Sports drinks make cyclists perform better] ??
Agree as the figure showed this, the placebo cyclists weren't able to carry on after 3 hours whereas when given sports drinks they were able to. The cyclists performance was generally much higher when given the glucose drink. taken over a period of a week
Disagree as it may not help performance because it was tested on a stationary bike at a constant speed which isn't realistic for a race. At around 2 (or 3) hours the glucose fuelled cyclists had a large drop in performance which would not help them in a race. Not enough cyclists tested on, increase the number.

[Explain how the increased breathing rate, heart rate and concentration of glucose improve the athlete's performance]
~Increased breathing rate
= more oxygen to go into blood to be used for respiration, lets aerobic respiration happen which causes no lactic acid to build up so cyclist can continue to go
= more opportunity for carbon dioxide to be expelled

~Increased heart rate
= heart beats more so pumps more blood which takes more glucose and oxygen to cells for respiration to release energy so cyclist can be stronger

~Concentration of glucose
= Raise the amount of respiration that can be done with more glucose so more energy can be released which provides the cyclist with more energy

4) [What starch breaks down into]
Starch --> Sugars

[Control variables of starch experiment]
- Same volume of amylase
- Same volume of starch
- Same amount of time given for starch to break down

[Iodine colour]
4 minutes = Dark Blue
6 minutes = Light brown

[Improvements to the experiment]
- Repeat at the different pH levels
- Use smaller intervals of pH between 6-8 to get a more accurate result

[Suggest what happens to Amylase in pH 3]
It gets denatured so won't work in these conditions or (possibly) the reaction will slow down even further

5) [Equation for photosynthesis]
Carbon dioxide + Water --> Glucose and Oxygen

[Arbitrary units at 0.04%]
16 arbitrary units

[Percentage increase in arbitrary units from 0.04% to 0.08%]
25% increase
- Increase from 16 to 20 was 4.
-One way to work it out is to do (4/16) x 100% = 25%
-- You use 4 as the increase and 16 as your original number to work out the change.

[Why farmers shouldn't use more than 0.08%]
Causes more global warming, costs more, it's no more effective to use over 0.08% as everything above this has the same arbitrary units - therefore it would be a waste

[Changes the farmer could make to raise photosynthesis]
-Increase light
-Increase temperature

6) [What is an allele?]
Different forms of the same gene

[Type of cell division]
Mitosis

[How many chromosomes in a human cell?]
46 chromosomes

[Number of divisions to get to 16 cells]
4 divisions

[What does recessive mean?]
A non dominant allele that must have two copies for it to show

[What does heterozygous mean?]
Two different alleles

[Ethical disadvantage of embryo screening]
Could harm the embryo or the mother

[Advantage of embryo screening]
Stop the suffering of the child, find out if the child had a genetic disorder

[Genetic cross diagram]
You should get NN, Nn, Nn and nn
- so the possibility of 25% or 1/4

7)[What is a species?]
A group of organisms that have common genes and can interbreed to produce fertile offspring

[How do we use fossils to see how species today have evolved from simple organisms?]
-Fossil record
-evidence of previous species
-can provide comparisons
-Shows the bones
-etc.

[Different species question]
-Geographical isolation
-Speciation (can't interbreed)
-Adaptation and mutation
-Natural selection
- Similar characteristics due to few changes as there's reasonably similar environments
-Dinosaurs not hunting them so no need to fly

Thanks for the UO mark schemeI quiet harshly marked mine and got 37 and what grade would it be roughly

oml, from this it seems as though i've gotten around 49 marks whilst being harsh
What dyu guys predict the grade boundries will be though?
I personally think:
A* - 46
A - 37
B - 28
C - 19
D - 12