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Aqa gcse 2017 biology unit 3 unofficial mark scheme

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Reply 180

Arifali4

Original post by Exponential-1.5

What do you think the grade boundaries will be for triple?

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i think possibly 43-45 for an A*, 38 for an A and 30 for a B

Reply 181

andrea___m

For the coeliac disease question I also put that the capillaries were further away from the cells on the surface of the small intestine so the diffusion distance was increased?Idk

Reply 182

Michaelsmiles

b3 and b2 was so easy it felt like a breeze

Reply 183

Michaelsmiles

the lining from the villi and the capillaries was larger so there was less absorption of the nutrients and food

Reply 184

Tahmid12

What was the answer for question 4 b ii) (i think thats the right question number)
how was transpiration affected in the clear box

Reply 185

Idontlikeexams

Original post by Tanvirul5

no this girl is dumb, most of the answers did not come up in the exam.

Her answers seemed very logical to me

Reply 186

Idontlikeexams

Original post by help.2017

how did everyone find the exam? And predicted grade boundaries based on the level of difficulty?
Last year was 41 A*

Paper was relatively easy, I'm hoping for somewhere around the 50 mark, considering the triple grade boundaries are usually lower, I feel this paper was slightly easier than last year's paper so I'm guessing around 45 for an A*

Reply 187

Idontlikeexams

Original post by anna2811

I thought that the cell would shrink, because the solution was more concentrated on outside of the cell so water would move out by osmosis?

The blood cell would burst, as it's optimum concentration was 280 arbitrary units and the drink was 492 I think, osmosis has nothing to do with that question

Reply 188

help.2017

Original post by Idontlikeexams

last years exams was easier! but you could be right

Reply 189

keeleylsmith

I swear its just me who found the biology papers really hard this year, thats a D for me!

Reply 190

Y-NR

Original post by Idontlikeexams

The blood cell would burst, as it's optimum concentration was 280 arbitrary units and the drink was 492 I think, osmosis has nothing to do with that question

Actually, it does. Since the solution outside the cell is more concentrated (of glucose), there is a net movement of water particles from high to low (cell to outside) through osmosis. I did struggle to decide which one to use, but in numerous past papers and the "potato chip experiment", the substance that is considered to be moving is water, not sugar/glucose. Hence, the cell turns flaccid. I could be wrong, but this is a possible answer.

Reply 191

number0

Original post by Idontlikeexams

The blood cell would burst, as it's optimum concentration was 280 arbitrary units and the drink was 492 I think, osmosis has nothing to do with that question

Think the question was all about osmosis. Water moves from dilute to concentrated solutions so water moves from cell to the drink, the cell has less water and is dehydrated

Reply 192

Daniel Conway

For the question about how the man kept warm could you write about how the hairs on his skin stud up for insulation??

Reply 193

msar

Original post by number0

i thought due to the solution around the cell being more concentrated, the water moves from the cell into the solution due to osmosis down concentration gradient. Cause like dehydration in the cell

this is correct!!!!!!!

Reply 194

msar

Original post by daniel conway

for the question about how the man kept warm could you write about how the hairs on his skin stud up for insulation??

yes definitely just had to explain in detail

Reply 195

R0se3

Original post by Tahmid12

What was the answer for question 4 b ii) (i think thats the right question number)
how was transpiration affected in the clear box

i said that the box ment that when the water evaporated it stayed in the air instead of being able to spread out. this means the concentration of water in the air was increases so evaporation happened at a slower rate meaning less water was lost so the mass of the apparatus was higher

Reply 196

zxnfina

Original post by etothepiiplusone

I am 90% certain the revision guide lists the two waste products in the body as urea and CO2. I therefore think for 5-6 marks you had to talk about both of these.

Guess I did it wrong then😂 I just went into detail about the kidney and what they filter like water, ions, urea and glucose which re-absorbs

Reply 197

zxnfina

Original post by Tahmid12

What was the answer for question 4 b ii) (i think thats the right question number)
how was transpiration affected in the clear box

Wasn't it a dark box, i put that the stomata closes when its dark therefore transpiration doesn't occur so there is less water loss and will weigh more then the other ones (because it asked you to compare with the other experiment)

Reply 198

zxnfina

I think it was an easy paper overall, but it was easy to make mistakes by talking about something else in that topic

Reply 199

meemzks

there was a question about coeliac disease? on the higher aqa b3 paper??? where? i just had questions about deforestation and trees at the beginning i?????