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A2 Biology OCR June 2015 Revision Thread

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guys, I'm confused about the neurones and how to label the parts. Especially the difference between the dendron and axon. And also are both sides of the neurone (motor and sensory) dendrites?

Axon carries impulses AWAY from cell body
Dendron carries impulse TOWARDS cell body

As motor neurones carry impulses AWAY from CNS and have their cell bodies at the end of their structure, they have a long axon and NO Dendron. :smile:

(edited 8 years ago)

Reply 2101

Meesh14

Original post by leerachelll

guys, I'm confused about the neurones and how to label the parts. Especially the difference between the dendron and axon. And also are both sides of the neurone (motor and sensory) dendrites?

dendrons are in the direction towards the cell body in sensory neurones and the axon is away from cell body.

motor neurones only has a axon.

dendrites are the things on the cell body of the motor neurone

Reply 2102

Maham88

Original post by Molly_xox

Yes this is what I've learned.

Substrate level phoshorylation:
2 ATP from glycolysis,
2 ATP from Kreb's

Then for oxidative:
2 reduced NAD from glycolysis
2 reduced NAD from link reaction
6 reduced NAD from Kreb's
TOTAL = 10 red. NAD

Each NAD roughly makes 2.6 ATP, so 26+4 = 30.

But I'm not sure where FAD fits into that...

FAD is reduced in the kreb cyle and i think that gives the 2 ATP

Reply 2103

Maham88

Original post by Munrot07

Officially (according to OCR) NAD = 2.5 ATP and FAD = 1.5ATP

10 NAD = 25 ATP
2 FAD = 3 ATP
4 ATP from earlier

32 overall :smile:

In the book it says NAD =2.6

Reply 2104

coolerthanbeans

Original post by tewas

why should there be no air bubbles in a photosynthometer?

Would give an invalid result, because since a photosynthometer measures volume of oxygen collected in capillary tube, if there was an air bubble in there beforehand, then it would seem like more oxygen was produced than there actually was.

Reply 2105

Molly_xox

Original post by leerachelll

guys, I'm confused about the neurones and how to label the parts. Especially the difference between the dendron and axon. And also are both sides of the neurone (motor and sensory) dendrites?

Only sensory neurones have a dendron. The dendron goes from the receptor end to the cell body. The axon goes from the cell body towards the CNS. (Axon = away from cell body).

I think at the effector end of a motor neurone and the CNS end of a sensory neurone they're called 'axon terminals', but I'm not 100% sure, will check my notes in a sec.

EDIT: the branches are axon terminals, the swellings are neurotransmitter swellings. The diagrams in these notes are pretty clear for the labelling. :smile:

http://www.thebiotutor.com/uploads/2/7/2/8/27287711/f214_1b_nerves_notes.pdf

(edited 8 years ago)

Reply 2106

Munrot07

Original post by Maham88

In the book it says NAD =2.6

In my book it's always said 2.5 :s-smilie:

They must have updated it since I got mine. Perhaps 33 ATP are made then?

Reply 2107

Maham88

Original post by Munrot07

In my book it's always said 2.5 :s-smilie:

They must have updated it since I got mine. Perhaps 33 ATP are made then?

they don't even say how many ATP molecules FAD makes , and the total yield of ATP is 30 in the book .

Reply 2108

BioAgent

what do we need to know about the experiment to measure rate of photosynthesis?

Reply 2109

WBN

Original post by Munrot07

In my book it's always said 2.5 :s-smilie:

They must have updated it since I got mine. Perhaps 33 ATP are made then?

I would think that 32 ATP is a theoretical yield

Reply 2110

it's a me, mario

Who is going to fail f215 :frown:

Posted from TSR Mobile

Reply 2111

Student23478

Guys how can you tell the difference when labelling myelin sheath or Schwann cell????

Reply 2112

LMottram

So does the Vagus nerve and Accelerator nerve connect the Sinoatrial node to the Medulla oblongata?
Or do they connect the chemoreceptors and baroreceptors to the Medulla oblongata?
Thanksss :biggrin:

(edited 8 years ago)

Reply 2113

Munrot07

Original post by Maham88

they don't even say how many ATP molecules FAD makes , and the total yield of ATP is 30 in the book .

They have definitely changed it since by time then. I think OCR have done a bit of lying to simplify things, they do that a lot. Doing some quick research online and from my university lectures it says NAD = 2.5 and FAD = 1.5. However, two of the molecules of NAD (the ones made in glycolysis) sometimes switch to 1.5 (apparently due to the fact one H+ is required to transport NADH into the mitochondria) so the yield is either 32 or 30 depending on the way those two NADs are so inclined.

Original post by WBN

I would think that 32 ATP is a theoretical yield

Actually the theoretical yeild is about 38 as theoretically NAD = 3 and FAD = 2 however this is never achieved.

(edited 8 years ago)

Reply 2114

BioAgent

photosynthesis experiment?

Reply 2115

Molly_xox

Original post by LMottram

So does the Vagus nerve and Accelerator nerve connect the Sinoatrial node to the Medulla oblongata?

Yes. Accelerator nerve is for the sympathetic NS so triggers an increased heart rate. Vagus is for the parasympathetic NS so triggers a decreased heart rate.

(edited 8 years ago)

Reply 2116

Maham88

Original post by Munrot07

They have definitely changed it since by time then. I think OCR have done a bit of lying to simplify things, they do that a lot. Doing some quick research online and from my university lectures it says NAD = 2.5 and FAD = 1.5. However, two of the molecules of NAD (the ones made in glycolysis) sometimes switch to 1.5 (not sure why) so the yield is either 32 or 30 depending on the way those two NADs are so inclined.

Actually the theoretical yeild is about 38 as theoretically NAD = 3 and FAD = 2 however this is never achieved.