OCR A Level Biology Biological processes H420/01 - 9 Jun 2022 [Exam Chat]

Is there another thread for paper 2 and if there is can someone link it please? Also what is classed as cellular control from the advanced info because it could be so many things ???

Reply 1401

Spectrz

6

Original post by CHLOSHMONEYYY

Is there another thread for paper 2 and if there is can someone link it please? Also what is classed as cellular control from the advanced info because it could be so many things ???

Look at cellular control on the specification.

Reply 1402

borat32

5

Original post by WoodsterJ15

That was right what you did. Strenuous Exercise is High Intensity Exercise (Anaerobic) so you needed to talk about Phosphocreatine and Anaerobic Respiration

I did all 3, would I get marked down for including the aerobic part?

Reply 1403

adddsfgyyhjk

9

Original post by borat32

I did all 3, would I get marked down for including the aerobic part?

i think you need to say it because at the start they must be respiring aerobically

Reply 1404

peepeedd

16

Original post by adddsfgyyhjk

i think you need to say it because at the start they must be respiring aerobically

And it’s a six marker, imagine you need all three. Worst case scenario, you don’t have to but you won’t lost marks for it

Reply 1405

username5825061

11

Original post by Ish2186

Positive AND negative feedback. Think about insulin and glucagon and how blood glucose concentration is controlled. That’s an example of homeostasis. The temp one said to maintain a ‘constant’ internal temperature - i interpreted that as having no fluctuations and staying the same which is obviously not true so

Positive feedback is not part of homeostasis. Positive feedback causes levels to move away from the normal range, that is not homeostasis.

Negative feedback mechanisms return levels back to a normal a range, that is homeostasis.

Insulin and glucagon work in a negative feedback mechanism. They are secreted when glucose level goes too high/low and they bring the glucose concentration back to normal.

And we do maintain a relatively constant internal temperature. It is usually kept within plus or minus 1 degree.

(edited 1 year ago)

Reply 1406

Biogeo07

3

Anyone remember how many marks the plant transport system question was?

Reply 1407

heyyyyy_64

8

Original post by Biogeo07

Anyone remember how many marks the plant transport system question was?

3 marks

Reply 1408

Agent047

6

https://www.sciencephoto.com/media/29001/view/spirally-thickened-xylem-tubes
Looks familiar 👀
Ig that confirms the holes are pits not plasmodemata

Reply 1409

Agent047

6

Also I'm pretty sure I completely bombed the fish question, but does anyone think that making sure fish are well fed with carbohydrate heavy meal before the practical so that they only respire carbs instead of alternative substrates which use up different amounts of oxygen affecting oxygen consumption would be a valid thing the scientists must control. Looking back on my answers to that question they all seem very wrong but seems the least wrong so I'm hoping it's right since I'm low key getting paranoid that I might end up choking an A*

Reply 1410

lol2468

Universities Forum Helper

14

Original post by Agent047

https://www.sciencephoto.com/media/29001/view/spirally-thickened-xylem-tubes
Looks familiar 👀
Ig that confirms the holes are pits not plasmodemata

lol its the exact same one

(edited 1 year ago)

Reply 1411

hiiiiiiye2ue89

10

Original post by Agent047

Also I'm pretty sure I completely bombed the fish question, but does anyone think that making sure fish are well fed with carbohydrate heavy meal before the practical so that they only respire carbs instead of alternative substrates which use up different amounts of oxygen affecting oxygen consumption would be a valid thing the scientists must control. Looking back on my answers to that question they all seem very wrong but seems the least wrong so I'm hoping it's right since I'm low key getting paranoid that I might end up choking an A*

Idk if the point is valid but the fact of the matter is that you need abut 70% for an A*, that isn't the highest so the likelihood of that question being the defining factor is minimal

Reply 1412

Spectrz

6

Original post by Agent047

https://www.sciencephoto.com/media/29001/view/spirally-thickened-xylem-tubes
Looks familiar 👀
Ig that confirms the holes are pits not plasmodemata

damn that sucks, it really looks like a phloem sieve tube with the perforated plates.

Reply 1413

treasuremaker

9

Original post by KMaisey

Positive feedback is not part of homeostasis. Positive feedback causes levels to move away from the normal range, that is not homeostasis.

Negative feedback mechanisms return levels back to a normal a range, that is homeostasis.

Insulin and glucagon work in a negative feedback mechanism. They are secreted when glucose level goes too high/low and they bring the glucose concentration back to normal.

And we do maintain a relatively constant internal temperature. It is usually kept within plus or minus 1 degree.

yh but surely they would say it was kept relatively constant then? i kind of assumed by constant, it meant the same level all the time

Reply 1414

username5825061

11

Original post by treasuremaker

yh but surely they would say it was kept relatively constant then? i kind of assumed by constant, it meant the same level all the time

Homeostasis can't maintain an exactly constant value of anything, but it can maintain it within a nornal range. The definition in my OCR student book is "homeostasis is the maintenance of a constant internal environment. It involves control systems that keep your internal environment roughly constant (within certain limits).

And internal temperature is kept relatively constant, with a range usually between 36 - 37 degrees.

However I have already forgotten what the exact question was and what the other options were. The exam is already a blur in my mind now, probably for self preservation of sanity because of going over all the marks i know i have lost.

(edited 1 year ago)

Reply 1415

Iceyballz

8

anyone remember what they put for evaluating the farming temp of 18 degrees? i put something about a bigger increase from 13 to 18 degrees in respiration, and a smaller increase from 18 to 23, suggesting its not worth the energy to heat those extra 5 degrees

Reply 1416

Iceyballz

8

oh this thread is dead i forgot

Reply 1417

nessy7

6

Original post by Iceyballz

anyone remember what they put for evaluating the farming temp of 18 degrees? i put something about a bigger increase from 13 to 18 degrees in respiration, and a smaller increase from 18 to 23, suggesting its not worth the energy to heat those extra 5 degrees

i kinda said something along those lines i also waffled about how 23 degrees is closer to room temp so u would use less energy for 23 so its more economical for the farmers, probs not correct tho lmao