OCR Biology F214 Communication, Homeostasis and Energy Wed 25 Jan 2012

nope thats right :smile:

we don't actually need to know it for this exam but you'd probably get marks for it if its a question like 'name a hormone' and you somehow forget adrenaline ( :confused:

)

Noradrenaline is a neurotransmitter not a hormone. ;]

Reply 981

faz_341

Original post by The Illuminati

+40mV for threshold value

-50mV for threshold vlaue
actio potential is at +40mV

Reply 982

VQG

11

Can anyone confirm my knowledge of respiratory acidosis?
Is it the high concentration of CO2 in the blood lowering the pH of the blood (CO2+H20 --> H2CO3 <==> H+ HCO3-)
Detected by chemoreceptors in the cardiovascular center of the brain in the Medulla Oblongata. Medulla oblongata sends an action potential down to the heart via the accelerator (sympathetic) nerve which raises the heart rate, to try eliminate the CO2. Can result in even more CO2 accumulating hence more carbonic acid, which stops the heart functioning (heart attack).

Reply 983

Bi0logical

7

What is the role of the Kidneys in osmoregulation?

Reply 984

Claudine

14

Original post by Messara2

how do you know whether do divide by 24 or by 60?

Divide by the first number :smile:

Reply 985

The Illuminati

4

Original post by Chris P Chicken.

Noradrenaline is a neurotransmitter not a hormone. ;]

It's also a hormone. Like adrenalin acts as a hormone and a neurotransmitter.

Reply 986

Bi0logical

7

Original post by VQG

Can anyone confirm my knowledge of respiratory acidosis?
Is it the high concentration of CO2 in the blood lowering the pH of the blood (CO2+H20 --> H2CO3 <==> H+ HCO3-)
Detected by chemoreceptors in the cardiovascular center of the brain in the Medulla Oblongata. Medulla oblongata sends an action potential down to the heart via the accelerator (sympathetic) nerve which raises the heart rate, to try eliminate the CO2. Can result in even more CO2 accumulating hence more carbonic acid, which stops the heart functioning (heart attack).

Your right but you need to know that it's not actually the CO2 that's causing the respiratory acidosis, the CO2 first forms carbonic acid, this then dissociates into H+ ions like you mentioned in the formula, this increases the pH which have an effect on enzymes (may cause muscle fatigue) tiredness, etc

Reply 987

Claudine

14

Hey can anyone help me?

How would I answer a qauestion on the evidence for chemiosmosis?

thanks

Reply 988

DeelyBopper

16

Original post by Chris P Chicken.

Noradrenaline is a neurotransmitter not a hormone. ;]

its both

Reply 989

The Illuminati

4

Original post by faz_341

-50mV for threshold vlaue
actio potential is at +40mV

that's what i meant.

Reply 990

TourettesUnicorn

Original post by thestudentroo

for i) 125X24X60 = 180 000
ii) 180 000 -1500 = 178500
178500/ 180 000 = 99.12%

Got it the second time when i read the question properly :smile:

Reply 991

Dan12

In endotherms, body heat is maintained by signaling the mitochondria to allow protons to run back along the gradient without producing ATP.[citation needed] This can occur since an alternative return route for the protons exists through an uncoupling protein in the inner membrane. This protein, known as uncoupling protein 1 (thermogenin), facilitates the return of the protons after they have been actively pumped out of the mitochondria by the electron transport chain.

Suggest why this uncoupling process is so important in the brown fat of humans

Reply 992

im so fresh

12

oh wow just realised this thread is going to reach 1000 posts :biggrin:

we are dedicated to biology!!

Reply 993

plummango

Original post by Chris P Chicken.

Osmosis is correct :biggrin:

Ok damn, my mind is going mad.

Thanks for telling me its osmosis.

Although, I would've end up writing Osmoregulation in the exam!

Reply 994

xRainbowx

I know there are cells lining the Proximal convoluted tubule, but is the actual tubule itself made up of cells or is it just a space?

Reply 995

TourettesUnicorn

Studying facilitated diffusion in the nephron always makes me need the loo....

Reply 996

Chris P Chicken.

Original post by Dan12

In endotherms, body heat is maintained by signaling the mitochondria to allow protons to run back along the gradient without producing ATP.[citation needed] This can occur since an alternative return route for the protons exists through an uncoupling protein in the inner membrane. This protein, known as uncoupling protein 1 (thermogenin), facilitates the return of the protons after they have been actively pumped out of the mitochondria by the electron transport chain.

Suggest why this uncoupling process is so important in the brown fat of humans