Biology B3 Mark Scheme 21/05/12

Can you email me my chemistry notes and your physics notes please? I lost everything when my computer broke. ._.

Also, in 1b I didn't use the word 'more' so do I get 0 marks for it?

I will email them both to you now. Hmm, I'm not to sure.. In the past with questions like that, the mark schemes do focus on the word more, as that's the whole point in the increased blood flow..

What did you put exactly?

Reply 281

mazam

1

For the last question could you say they would want to prevent DAS from growing as it would result in less competition for food?

The 0.62 answer, i multiplied it by 100 and wrote 62, how many marks would that get? (Forgot if i put a percentage in)

And for the question as to why the glucose cant absorb the maltose i wrote 'the maltose is two glucose put together'?

I need 94 UMS for a A*, but i dont think i did that well on the paper as i made a couple of silly mistakes. How many marks is estimated i need for 94 Ums?

Reply 282

Jamo9809

5

How did I do :/ ? I need 85 UMS for an A* overall, what do you think i have got :/ please someone help im quite nervous about what i've got.

1a) i) There are six sharp fluctuations between 7.5 and 18 minutes. (1)
ii) 2.5 minutes (1)
b) Supply oxygen (1), glucose (1), remove carbon dioxide (1) , remove lactic acid (1), more aerobic respiration, more energy released and muscles are respiring faster and can work for longer (Max 4)
2 ai) To maintain anaerobic conditions and to exclude the oxygen so that aerobic respiration did not occur. The seal ensured no oxygen entered the flask.
ii) Carbon dioxide (1)
b) 0.62 (2)
ii) Adding fish fat, increases yield of biogas/methane (1). Better quality biogas, as higher proportion of methane (1). Quoted figure increase (1)
c) The increase in methane yield is not high enough to justify the costs so it would not be cost-effective for Olaf to buy fish-fat(1).
3 a) Aerobic (1) respiration (1)
ii) So that the fusarium is kept / maintained at an even and optimum temperature. (Max 1)
b) The long fibres would get damaged by the paddles (1).
c) Chicken has more protein for making new muscle cells (1).
ii) Less fat, so less risk of circulatory problems (1). More dietary fibre, reduces risk of colon cancer (1).
4a) Higher concentration in plant roots than in soil, so absorption against the concentration gradient (1). Diffusion is from a high to low concentration so active transport would have to be used to absorb the ions(1).
ii) Active transport (1).
b) i) Larger surface area (1)
ii) Mitochondria site of respiration in a cell (1), so more mitochondria results in more respiration, increasing rate of active transport and more energy is released for it to occur(1).
iii) Starch can be turned into glucose and this can be used as an energy source for aerobic respiration (1).
5 a) Urea and ions (2)
b) All of the glucose is ultrafiltrated in the bowmans capsule where all of it passes out of the bloodstream and into the kidney tubules. At the end of the kidney ALL of the glucose is reabsorbed by active transport so it is all uptaken. (MAX 3)
c) A diabetic will have high concentrations of glucose in their blood so the body will need to get rid of it therefore some of the glucose is not reabsorbed and passes on into the urine (MAX 2)

6a) Increasing DAS concentration does not affect glucose or sucrose. DAS only results in less maltose being fermented for example at 5cm^3 it was reduced by more than half to 48% (or whatever it was :P) and at 15cm^3 it was reduced to only a 2% yield. (MAX 4)
b) Maltose is two glucose linked together so the yeast wouldn't be able to absorb it (sugar too complex) (1)
c) The DAS kills the enzyme so that fermentation cannot occur. If DAS is not present this means that the yeast can release an enzyme molecule, therefore the maltose can be broken down into two simpler glucose molecules which can be absorbed and digested by the yeast for use in aerobic respiration (MAX 3)
d) DAS reduces yield of alcohol, the DAS makes the process of fermentation less efficient by reducing level of maltose fermentation (MAX 2 )

PLEASE TELL ME ?

(edited 11 years ago)

Reply 283

Phteven

15

Original post by g.k.galloway

well I'm really hoping for 100ums to get an A* overall (i need 97ums)... so really i need high end 30's /low 40's... knowing me i'll get my overall biology grade and be one ums off an A*

yeh that jan b2 was horrible, I got an A* too!

I need 99 UMS to get an A* in Biology. Good luck!
P.S. This is my first post EVER and it's in reply to you - feel special! :wink:

Reply 284

Examstressman

in urine, do you reckon it counts to say

Urea & Salt?

i put mineral ions then crossed it out, silly me :/

Reply 285

Cubic

8

Original post by CharlieBoardman

I will email them both to you now. Hmm, I'm not to sure.. In the past with questions like that, the mark schemes do focus on the word more, as that's the whole point in the increased blood flow..

What did you put exactly?

Thanks, and I put:

To maintain excercise aerobic respiration must occur to produce energy, for this oxygen is neccesary therefore it travels through the blood stream (by reacting with haemoglobin to form oxyhaemoglobin), this is a reversible reaction so the oxyhaemoglobin will release the oxygen to allow the respiration to occur. Without this, anaerobic respiration will occur producing lactic acid and causing fatigue which is bad for excercise.

Reply 286

Jamo9809

5

Please someone reply :frown:

Reply 287

CharlieBoardman

14

Original post by Cubic

Thanks, and I put:

To maintain excercise aerobic respiration must occur to produce energy, for this oxygen is neccesary therefore it travels through the blood stream (by reacting with haemoglobin to form oxyhaemoglobin), this is a reversible reaction so the oxyhaemoglobin will release the oxygen to allow the respiration to occur. Without this, anaerobic respiration will occur producing lactic acid and causing fatigue which is bad for excercise.

Well, the exact same question was on the June 2010 Paper, this is what the mark scheme says word for word:

increased aerobic respiration
or
decreased anaerobic respiration

increased energy supply / need

less lactic acid formed or to breakdown lactic acid or less O2-debt

can do more work or can work harder / faster / longer

or less fatigue / cramp / pain

(edited 11 years ago)

Reply 288

mazam

1

Original post by CharlieBoardman

Well, the exact same question was on the June 2010 Paper, this is what the mark scheme says word for word:

increased aerobic respiration
or
decreased anaerobic respiration

increased energy supply / need

less lactic acid formed or to breakdown lactic acid or less O2-debt

can do more work or can work harder / faster / longer

or less fatigue / cramp / pain

Is writing less lactic acid in todays question right? Because thats only formed when we anareobically respire and it doesnt mention anaerobic conditions in the question.

Reply 289

CharlieBoardman

14

Original post by mazam

Is writing less lactic acid in todays question right? Because thats only formed when we anareobically respire and it doesnt mention anaerobic conditions in the question.

Well yes. If you have more oxygen, you aerobically respire more, which means you don't anaerobically respire as much, meaning you produce less lactic acid

Reply 290

mazam

1

Original post by CharlieBoardman

Well yes. If you have more oxygen, you aerobically respire more, which means you don't anaerobically respire as much, meaning you produce less lactic acid

So would writing :
to oxidise the painful lactic acid into carbon dioxide and water, be the right answer to todays question as to how the increase heart rate is useful?

Reply 291

StateSchooler95

Original post by Basit2010

I would not think so as fermentation is anerobic respiration not aerobic.

No mate, the question was worth 2 marks - I think you'll get one mark since the correct answer was Aerobic(1) Respiration(1)

Reply 292

usycool1

19

Original post by mazam

So would writing :
to oxidise the painful lactic acid into carbon dioxide and water, be the right answer to todays question as to how the increase heart rate is useful?

I'd say the lactic acid isn't "painful," but it actually decreases the pH so enzymes in the muscle cells may become denatured. :smile:

Of course, Charlie can tell me if what I'm saying is right or not :smile:

(edited 11 years ago)

Reply 293

prem74

This has been a great help. Thanks op.
Could anyone provide the questions alongside this mark scheme? Thanks.
How do you manage to remember all of your answers?

Reply 294

Aarongreatbanks

I think, being really critical (taken any marks that they could consider taking away, away) and i get 33/45. i need 77 UMS for A* what's my chances. This obviously isn't accurate as it's against the unnoficial one but still whats the chances?

Reply 295

CharlieBoardman

14

Original post by usycool1

I'd say the lactic acid isn't "painful," but it actually decreases the acidity so enzymes in the muscle cells may become denatured. :smile:

Of course, Charlie can tell me if what I'm saying is right or not :smile:

Original post by mazam

So would writing :
to oxidise the painful lactic acid into carbon dioxide and water, be the right answer to todays question as to how the increase heart rate is useful?

I think the point of the question is the emphasis on MORE and LESS. You would still get a mark for that though :smile:

What else did you write?

Reply 296

tinkerbell1109

Is the predicted A* boundary 34 for this paper? Please reply =)

Reply 297

stenhorse

2

I was wondering how you all got 0.62g?
I got 0.615, everyone's saying 0.62, so I figure that's right, i'm just curious how you came to it
I added 0% fish fat and 5% fish fat (0.6+0.63) to get 1.23 and divided it by 2 to get 2.5% of fish fat = 0.615
Someone please correct me :L

Reply 298

flyhigh99

2

Original post by stenhorse

I was wondering how you all got 0.62g?
I got 0.615, everyone's saying 0.62, so I figure that's right, i'm just curious how you came to it
I added 0% fish fat and 5% fish fat (0.6+0.63) to get 1.23 and divided it by 2 to get 2.5% of fish fat = 0.615
Someone please correct me :L