OCR Biology F214 Communication, Homeostasis and Energy Friday 22 June 2012

Can someone send me their notes please I'm so screwed

Excretion

http://getrevising.co.uk/resources/ocr_excretion

Respiration

http://getrevising.co.uk/resources/ocr_respiration1

Photosynthesis

http://getrevising.co.uk/resources/ocr_photosynthesis

I don't have any on the first module I'm afraid

Reply 381

corpuscallosum

10

Ok guys, about controlling heart rate - am I right in saying that there are stretch receptors in both the muscles and the carotid sinus, and that the ones in the muscles detect stretch by exertion and the ones in the carotid sinus detect (dangerously) high blood pressure?

Reply 382

arvin_infinity

3

Original post by YB101

x

You reckon there will be labelling question on dialysis machine!

Reply 383

stben01

Omg ppl!! Khan academy vids on photosynthesis and EVERYTHING are brilliant and explains everything really clearly!! Check it out:

PS OVERVIEW
http://www.youtube.com/watch?v=-rsYk4eCKnA&feature=youtube_gdata_player

PS LIGHT REACTION
http://www.youtube.com/watch?v=GR2GA7chA_c&feature=youtube_gdata_player

PS CALVIN CYCLE
http://www.youtube.com/watch?v=slm6D2VEXYs&feature=youtube_gdata_player

This was posted from The Student Room's iPhone/iPad App

Reply 384

YB101

17

Original post by arvin_infinity

You reckon there will be labelling question on dialysis machine!

Could be, if so check the past papers because it has come up before

Reply 385

stben01

Yh but that's not do hard!! I'm more worried about the respiration questions!! So hard to revise for that!!

This was posted from The Student Room's iPhone/iPad App

Reply 386

JustMeAyshia

Original post by KeepBreathing

Can anyone explain what a respiratory quotient actually shows please? :smile:

An RQ shows the type of substrate being respired e.g. RQ of 1 - carbohydrates being respired,RQ of 0.7- lipids being respired and RQ of 0.9- proteins being respired. Also it can show whether aerobic or anaerobic respiration is taking place e.g RQ above one indicates anaerobic respiration whilst RQ of one and under is aerobic respiration.
Hope this helped :-)

Reply 387

kimmey

7

can someone please explain for me how the loop of henle actually works ? :smile:

Reply 388

arvin_infinity

3

Original post by YB101

Could be, if so check the past papers because it has come up before

Am confused..are you saying it has come up..or you telling me to check it myself

Reply 389

arvin_infinity

3

Original post by kimmey

can someone please explain for me how the loop of henle actually works ? :smile:

A bit more specific..might be able to explain :smile:

here is a ridiculously simplified version: loop of henle is involved in making the medulla salty and therefore lowering its water p so
creating a water potential gradient between medulla and the filtrate (in the loop of henle)

what is wrong with the spell checker..Henle is the right spelling :colone:

Reply 390

JustMeAyshia

Original post by kimmey

can someone please explain for me how the loop of henle actually works ? :smile:

The loop of henle works to create a low wp in the medulla allowing water reabsorption

1)In the ascending limb na+/cl- ions are actively pumped out into the medulla this lowers the wp in the medulla due to.a build up of a high concentration of ions -the ascending is impermeable to water
2) in the descending limb water moves out into the medulla by osmosis - the wp of the medulla is lower than the descending limb - this further lowers the wp so water is reabsorbed into the blood through the capillary network
3) near the bottom of the ascending limb na+cl- ions are pumped out into medulla further lowering wp
4) the first 3 increase ion concentration in the medulla lowering wp so water can be reabsorbed into the blood through the capillary network

Reply 391

JustMeAyshia

Oh i forgot to mention at point four this causes water to move out of the collecting duct by osmosis :-)

Reply 392

Sparkzz

4

Original post by corpuscallosum

Ok guys, about controlling heart rate am I right in saying that there are stretch receptors in both the muscles and the carotid sinus, and that the ones in the muscles detect stretch by exertion and the ones in the carotid sinus detect (dangerously) high blood pressure?

yepp, the ones in the carotid sinus (present in the carotid artery) detect changes in bp..

Reply 393

YB101

17

Original post by arvin_infinity

Am confused..are you saying it has come up..or you telling me to check it myself

I'm saying that it HAS definitely come up before, a question on labelling a dialysis machine. But if I was you I'd pay particular attention to the long answer questions, make sure you know what you need to include to get full marks because the marking points are usually about 15-20 for a 8 or 9 mark question. Also, pay attention to topics that HAVEN'T come up because as we all know OCR are horrible :smile:

Reply 394

Groat

13

Does anyone find this harder than F215? There seems to be less room for mistakes. :s-smilie:

Reply 395

RachelM94

Original post by Groat

Does anyone find this harder than F215? There seems to be less room for mistakes. :s-smilie:

Definitely! at least in F215 its so big that you can afford to drop a few marks, but in this it feels like every single mark you drop will make you miss out on a grade D:
I think it's ridiculous that there's only 6 marks between grades!

Reply 396

Groat

13

The three mark suggest questions can be just as picky, but not as many marks in the paper to compensate!

I'll be revising all day tomorrow. :colone:

Reply 397

YB101

17

Does anyone know why the bigger the diameter of the axon, the faster the rate of conduction? I don't think it's in the book?

Reply 398

kimmey

7

Original post by arvin_infinity

A bit more specific..might be able to explain :smile:

here is a ridiculously simplified version: loop of henle is involved in making the medulla salty and therefore lowering its water p so
creating a water potential gradient between medulla and the filtrate (in the loop of henle)

what is wrong with the spell checker..Henle is the right spelling :colone:

aha i believe henle with an acute symbol is the correct spelling :wink:

yeh i just wanted to know how the ascending limb links to teh descending limb to lower the water p of the medulla etcc

Reply 399

kimmey

7

Original post by JustMeAyshia

The loop of henle works to create a low wp in the medulla allowing water reabsorption

1)In the ascending limb na+/cl- ions are actively pumped out into the medulla this lowers the wp in the medulla due to.a build up of a high concentration of ions -the ascending is impermeable to water
2) in the descending limb water moves out into the medulla by osmosis - the wp of the medulla is lower than the descending limb - this further lowers the wp so water is reabsorbed into the blood through the capillary network
3) near the bottom of the ascending limb na+cl- ions are pumped out into medulla further lowering wp
4) the first 3 increase ion concentration in the medulla lowering wp so water can be reabsorbed into the blood through the capillary network

thanks, very helpful :smile:

OCR Biology F214 Communication, Homeostasis and Energy Friday 22 June 2012

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