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

Insulin secretion:
beta secretes insulin into the blood
target cells ( liver/ muscles)
glucose enteres via transporter proteins.
when insulin binds to the receptors on these cells, transporters ( GLUT4) found in the cytoplasm move towards the memrbane and bind. They merge the glucoe transporter protiens with the membrane, which allows glucose to enter down its conc. gradient.

Once inside, glucose get phosphoylated by glucokinase which traps gluoce within the cell, as it cannot leave through the transporters.
this activates an enzyme controlled reaction which forms glycosidic bonds, resulting in glycogenesis ( forming glycogen)

Reply 1041

cup

1

Original post by Chris P Chicken.

Medulla doesn't make sense as there are many 'medulla's"

There's a medulla in the kidney and the adrenal glands, so don't make that mistake in the exam!

It's what's in my textbook and notes!

Also, you said noradrenaline wasn't a hormone - it's infact both a hormone and neurotransmitter :P js teehee

Reply 1042

Leeshur

13

I'm ****ting myself over excretion. Liver + it's functions, piss easy. The kidneys are going to kill me. ; n ;

pls pls pls, respiration + photosynthesis questions OCR :C

Reply 1043

--NWzD9--

8

Original post by Lalaa

Insulin secretion:
beta secretes insulin into the blood
target cells ( liver/ muscles)
glucose enteres via transporter proteins.
when insulin binds to the receptors on these cells, transporters ( GLUT4) found in the cytoplasm move towards the memrbane and bind. They merge the glucoe transporter protiens with the membrane, which allows glucose to enter down its conc. gradient.

Once inside, glucose get phosphoylated by glucokinase which traps gluoce within the cell, as it cannot leave through the transporters.
this activates an enzyme controlled reaction which forms glycosidic bonds, resulting in glycogenesis ( forming glycogen)

Could we also say that another effect of insulin is that more glucose is respired?

Reply 1044

faz_341

Original post by The Illuminati

that's what i meant.

Reply 1045

Chris P Chicken.

Original post by cup

It's what's in my textbook and notes!

Also, you said noradrenaline wasn't a hormone - it's infact both a hormone and neurotransmitter :P js teehee

I know but I'm right about this medulla thing!

How can medulla be right...you wouldn't know if it was in the medulla for the kidney (renal medulla) or medulla oblangata!

Reply 1046

Lalaa

Original post by --NWzD9--

Could we also say that another effect of insulin is that more glucose is respired?

yer... cuz its stored so the cells can use it for respiration. it also means that the food inatke can be used for growth/ energy rather than respiration.

Reply 1047

Lalaa

REFRACTORY PERIOD: soduim channels CLOSE.

Reply 1048

Bi0logical

7

Remember the fourth vessel connected to the liver is not a blood vessel, it is the bile duct. Bile is a secretion from the liver. It has both a digestive function and an excretory function. The bile duct carries bile from the liver to the gall bladder where it is stored until required to aid digestion of fats in small intestine.

Reply 1049

Lalaa

really werid.. loooking at some past question:

explain how action potentials are transmitted in NON MYELINATED NEURONS and describ how there different from myeilnated ones...

the mark scheme : only decribes myelinated ones only??

Reply 1050

Bi0logical

7

So if FAD donates it's proton to oxygen (the final electron acceptor), does it also get dehydrogenated and it's H+ ions pumped into the intermembrane space by the energy released from electron carriers(electrons flowing through)

Reply 1051

Chris P Chicken.

Original post by Lalaa

really werid.. loooking at some past question:

explain how action potentials are transmitted in NON MYELINATED NEURONS and describ how there different from myeilnated ones...

the mark scheme : only decribes myelinated ones only??

Lol, well it shouldn't.

Which paper is this?

Reply 1052

im so fresh

12

Original post by Lalaa

really werid.. loooking at some past question:

explain how action potentials are transmitted in NON MYELINATED NEURONS and describ how there different from myeilnated ones...

the mark scheme : only decribes myelinated ones only??

non-myelinated=uses ionic currents-->causes a flow to overcome conc gradient(of ions)--->ions move from high conc to lower conc=flow

Reply 1053

Lalaa

Original post by Chris P Chicken.

Lol, well it shouldn't.

Which paper is this?

it says jan 2007

jan 10 guys? anyone?

Original post by Lalaa

really werid.. loooking at some past question:

explain how action potentials are transmitted in NON MYELINATED NEURONS and describ how there different from myeilnated ones...

the mark scheme : only decribes myelinated ones only??

Can you post da markscheme? That is weird. There has gtta be some marking points about local current somewhere...

Reply 1056

Lalaa

Original post by sumsum123

can you post da markscheme? That is weird. There has gtta be some marking points about local current somewhere...

Original post by lalaa

it says jan 2007

print screened

Original post by shyro1000

jan 10 guys? anyone?

http://www.ocr.org.uk/download/ms_10/ocr_50002_ms_10_gce_jan.pdf

Reply 1058

Bi0logical

7

do u we need to kno how to work out RQ VALUES

Reply 1059

Chris P Chicken.

Original post by Bi0logical

So if FAD donates it's proton to oxygen (the final electron acceptor), does it also get dehydrogenated and it's H+ ions pumped into the intermembrane space by the energy released from electron carriers(electrons flowing through)

It releases its hydrogen atom which is then split into electrons and hydrogen ions. The hydrogen ions from FAD are ONLY combined with O2 to produce water (they stay in the matrix).

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

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