EDEXCEL Biology B2

Hey there guys, apologies if this is a repeated thread but I could not seem to find any threads about the exam today on Biology B2 Edexcel.

I have some answers in mind but unfortunately do not know the question numbers.

I found it decent, just faltered a bit on the time - don't think 60 minutes is enough lol.

Anywho, how did you guys do?

Reply 1

Loolz5

I thought it was good actually, I liked the 6 marks and the general questions were easy to answer, and I really wanna get a good understanding of how many marks I got but I can't find an unofficial mark scheme which is frustrating. Hope it was good for everyone

Reply 2

Array00

Original post by Loolz5

Do you want to create one? An unofficial mark scheme with missing bits that we don't know and later we can have contributions.

Reply 3

Rof74

Original post by Argo00

Do you want to create one? An unofficial mark scheme with missing bits that we don't know and later we can have contributions.

Yeah we should create one 👍

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Reply 4

Rof74

1. Bacterial cell has flagellum, plasmid and chromosomal Dna ,whereas yeast has nucleus and mitochondria . Both have cytoplasm

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Reply 5

Array00

Hey there, sorry for the late reply. I remember answers to some questions but not the question number unfortunately. Here they are:

* Peristalsis. [1 mark]
* Question on the bread water and saliva: the saliva contains amylase which break down carbohydrates hence releasing sugar.
* Question on the bread water and saliva: the digaram does not correctly represent the small intestine because it does to portray the villi correctly.
* Fossils: talk about parts of a pentadactyl limb such as ulna, radius and phalanges.
* Last question talk about Xylrm and explain it. It carries water from the root of the plant, along the stem and to the leaves. Explain how roots spread to be able to reach for more water, and etc.

Reply 6

Rof74

Original post by Argo00

What did you get for "why do different parts of the plant have different amounts of chloroplasts?"

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Reply 7

Steven7376

Original post by Rof74

1. Bacterial cell has flagellum, plasmid and chromosomal Dna ,whereas yeast has nucleus and mitochondria . Both have cytoplasm

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Was that the only organelle you could've put down. If not what were the other ones?

Reply 8

student2607

There's a whole unofficial mark scheme here guys, saw it the other day as I did the same exam as you, it's: http://www.thestudentroom.co.uk/showthread.php?t=4155755&highlight=edexcel+b2#primary_content :smile:

Reply 9

Steven7376

Vessel W or Y can't remember was Pulmonary artery or Pulmonary vein...

Reply 10

Rof74

Original post by Steven7376

Vessel W or Y can't remember was Pulmonary artery or Pulmonary vein...

I think it was artery

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Reply 11

Rof74

Original post by Steven7376

Was that the only organelle you could've put down. If not what were the other ones?

I think it said to compare with bacterial cell

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Reply 12

Array00

Just for the people in this thread.

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)
Part(b):
Mitochondria. (1)
Part(c):
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):
Peristalsis
Part(b):
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)
Part(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(a):
Part(b):Break up proteins in cell membrane.
Part(c):
Part(d):
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(c):
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)

Leaves:

Part(a):
Part(b):
Part(c):
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.