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OCR Biology AS F211 May 2012

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Reply 160

Axion

Original post by Dagga

I havent revised really anything, revision starts now :confused:

Revise hard man. Good luck!

Reply 161

Folks

Anyone got a mark scheme with marking points for explaining the need for fetal haemoglobin to have a higher affinity for oxygen? I'm sure this topic will come up, and I feel like my explanation is too simple

Reply 162

Axion

Unfortunately not, but.

All it is is that fetal haemoglobin must have a higher affinity or the foetus would not be able to draw oxygen from the mothers blood. Therefore at any partial pressure, the foetus' affinity is higher than the mothers so the curve lies to the left of the mothers?

Reply 163

Dagga

Original post by Axion

Revise hard man. Good luck!

Thanks! Btw how are you revising so quickly?

Reply 164

Folks

Original post by Axion

Yes I'm probably worrying about nothing :rolleyes:

OCR can be so difficult with the way marks are awarded so I am always worried about losing easy marks for not hitting enough points

Reply 165

Axion

Original post by Dagga

Thanks! Btw how are you revising so quickly?

I don't know :redface:

just notes and textbook.

Reply 166

mathsclown

Original post by Axion

Would the partial pressure of oxygen always be lower at the fetus to cause the oxyhaemoglobin to dissociate so the fetal hb can take it up? Not quite sure since finishing off this topic today :/

Has anyone got any note on spirometer and how to calculate oxygen uptake? Hate it :frown:

Reply 167

Axion

Original post by mathsclown

i think so

finishing off cell division now. its a real annoyance

Reply 168

Axion

Anyone else starting to worry?

I've got a few more things on cell dvision to do, then re-revise everything, then read the textbook :/

:work:

Reply 169

Alotties

I'm the only one in my class sitting this exam woo!
Even though the majority of us got D's and U's in Jan (class of 8, there were 4 D's, 2 U's), I was the only one to opt to resit :confused:

But anyways my revision is going well but I'm scared that it will end up like Jan again where I ended up with a D :frown:

Reply 170

aisha302

Could someone explain the cardiac cyle please in like the simplest form & i really dont want to fail this help!

Reply 171

aisha302

Original post by Alotties

I'm the only one in my class sitting this exam woo!
Even though the majority of us got D's and U's in Jan (class of 8, there were 4 D's, 2 U's), I was the only one to opt to resit :confused:

But anyways my revision is going well but I'm scared that it will end up like Jan again where I ended up with a D :frown:

what mark did you get if you remember?
& good luck btw xo

Reply 172

Alotties

Original post by aisha302

what mark did you get if you remember?
& good luck btw xo

I got 52/90 UMS which was 32/60 raw marks =^.^=
One mark off a C so I'm hoping for at least a B this time!!
Did you take it?
Thanks for the luck, good luck to you too :tongue:

Reply 173

mathsclown

Original post by aisha302

Could someone explain the cardiac cyle please in like the simplest form & i really dont want to fail this help!

Filling Phase
Ventricles and atria relaxed
Blood flows from major veins through atria and through open AV valves into ventricles
This is diastole

Atria contration (atrial systole)
Heart beat begins with the contraction of the atria
Contraction creates small increase in pressure and pushes blood into ventricles
Once ventricles fill with blood they begin to contract
Blood flows upwards and fills in the pockets of rhe AV valves causes them to shut (prevents blood flowing back to atria)

Ventricular contraction
All valves are closed - ventricles contract
Pressure quickly rises
Once pressure is higher than the major arteries, semi lunar valves open and blood is pushed out
Ventricles relax and heart begins to fill with blood again for next cycle

(edited 11 years ago)

Reply 174

mathsclown

Stuff i didnt see in jan paper that may crop up: identify organelle, protein synthesis, mitosis, sperm cel or root hair cell, spirometer/ecg, heart and cardiac cycle, haemoglobin, single double open and closed circulatory system, Translocation and evidence for and agaisnt mass flow, tissue fluid, comparisons of vessel.

Good luck all, it is a pain but lets hope for the best :smile:

Reply 175

Axion

The big day tomorrow - may god have mercy on us all.

Reply 176

Axion

random questtion:

what creates hydrostatic pressure in the blood

Reply 177

Lil Monkey

Original post by Axion

random questtion:

what creates hydrostatic pressure in the blood

Contraction by the LEFT ventricle

:shy2:

anyone correct me if i am wrong!! (but thats what i learnt)

Reply 178

ohmyBEAUT

Original post by Lil Monkey

Contraction by the LEFT ventricle

:shy2:

anyone correct me if i am wrong!! (but thats what i learnt)

I'm sure it is the left ventricle. :smile:

Reply 179

Axion

tis :P the heart would do .

Anyone want to do a question exchange. whreby every post you write, has to end with a question and a set number of marks and the next person has to answer it?