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Edexcel A2 Biology Unit 5 (6BIO5) - 22/06/2011- OFFICIAL THREAD !

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Original post by tophothari
In one of the 5 mark question about ventilation, did anyone else put that Heart rate (beating rate) = ventilation rate/ tidal volume, hence as ventilation decreases and tidal volume increases, value for heart rate decreases.


Heart rate isnt connected to ventilation rate :s-smilie: at least not by a simple equation like that...

Ventilation rate = breathing rate x tidal volume
Cardiac Output = Heart rate x stroke volume

??
Original post by nadiaaraquel
core temp was ok as well, Had to mention that as temp increases the hypothalamus detects this temp change in the blood passing through it... so a heat loss centre is activated etcc...

and the other one, on why athletes A temp increase so much??


You mean he lost more water than the B guy?
Well it was a suggest question so any answers, plausible, is acceptable i guess.

I put something wrong with the negative feedback mechanism of A, maybe a tumor in hypothalamus. A could have had a higher proportion of body fat which could have acted as an insulator.
Will there be an unofficial markscheme for this exam released any time soon?

I messed up on the diagram for the shoot direction growth thing, but I think it was only 1 mark so no major harm done...
for putting macrophaages for the virus Q would i lose marks? i went on to explain the cell mediated response but i started of with saying macrophage become an APC :frown: but thats slightly inaccurate what do you lot think?
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Avatar for sunny10
sunny10
Other than the questions on calcium ions and fast twitch slow twitch, where i just waffled about the structure of the muscle sarcomere and the question about the breakdown of muscle protiens (just put some stuff about peptide bonds) I though it was a great exam. None of the stupid graph questions like the others and just about all of it was in the textbook.

I knew the agar jelly's had been switched over, but for some reason in my head i remember drawing it the other way... dayum, how many marks was it?

For heart rate and oxygen I put that heart rate increases blood pressure/how fast the blood moves in the vascular system. When it travels past the lung alveoli oxygen diffuses into the blood and co2 out in order to maintain an equilibrium. Increased movement of blood creates a steeper concentration gradient, meaning more diffusion occurs. More oxygen is therefore delivered to the rest of the body. Or something to that effect xD
Hey guys for that 5 marker question when you have to explain the negative feeback, from 60-100 minutes, I wrote everything about negative feedback i.e. thermoreceptors detect etc, everything except I forgot to mention the hypothalamus!! How stupid! Will I lose only 1 mark for this?
Original post by VetApplicant2011
Heart rate isnt connected to ventilation rate :s-smilie: at least not by a simple equation like that...

Ventilation rate = breathing rate x tidal volume
Cardiac Output = Heart rate x stroke volume

??


Oh.


Well.


****.
Hated this exam.
Original post by nadiaaraquel
core temp was ok as well, Had to mention that as temp increases the hypothalamus detects this temp change in the blood passing through it... so a heat loss centre is activated etcc...

and the other one, on why athletes A temp increase so much??


nahh got the first bit, it was the athletes one I meant.. I realised when we came out that it was because he had lost more sweat than the other stable dude, so he must have got dehydrated and couldnt sweat anymore, meaning his negative feedback mechanisms broke.. ah well
Original post by Phenylethylamine_
Hey guys for that 5 marker question when you have to explain the negative feeback, from 60-100 minutes, I wrote everything about negative feedback i.e. thermoreceptors detect etc, everything except I forgot to mention the hypothalamus!! How stupid! Will I lose only 1 mark for this?


Did you at least put that the info about stimulus is processed by CNS? And will I lose mark if i only gave 2 points (vasodilation and hair flat, i couldn't explain how the release of adrenaline worked) :/
Original post by tophothari
You mean he lost more water than the B guy?
Well it was a suggest question so any answers, plausible, is acceptable i guess.

I put something wrong with the negative feedback mechanism of A, maybe a tumor in hypothalamus. A could have had a higher proportion of body fat which could have acted as an insulator.


I said he sprinted for the last 40 minutes and the negative feedback mechansism couldnt keep up ahah *facepalm*
Original post by Phenylethylamine_
Yup, I got that for the myelin sheath and the centre was the axon. Umm, I wrote something along the lines that increase in heart rate increases oxygen uptake in blood because more impulses are sent from the medulla to the intercoastal muscles and diaphragm causing them to contract, inhaling in more air [i.e. greater oxygen uptake] I.e. signals sent from the inspiratory centre in the ventilation centres in the medulla.

No idea if that's right though!! :s-smilie:[/QUOT

I wrote something similar but also mentioned the stoke volume and loads of other nonsense haha. That was one of the few questions that were actually tricky I find.


what did you say about how the
membrane of a cell or an axon are "suited" to conduct and impulse? (something along those lines)
Original post by VetApplicant2011
I said he sprinted for the last 40 minutes and the negative feedback mechansism couldnt keep up ahah *facepalm*


i think for this one the answer was, he lost too much water, was dehydrated, so the sweating mechanism no longer functions as there is no water to lose, so body temp can no longer be controlled
Original post by tophothari
Did you at least put that the info about stimulus is processed by CNS? And will I lose mark if i only gave 2 points (vasodilation and hair flat, i couldn't explain how the release of adrenaline worked) :/


Yes, I wrote that the a change in deviation is detected by thermoreceptors etc and then the change in counteracted by the effector to get to back to the norm value. Basically, I mentioned everything besides hypothalamus! How stupid of me!! :mad:
Well, I mentioned vasodilation/sweating/hairs lieing flat, I think that should be enough
Original post by VetApplicant2011
Yeah it would, but they veryyyy sneakily swapped the old agar jellies around in the second diagram so it would grow the opposite way you think.

I dont think they were.. I think your only supposed to put three ticks? Il be happy if they were both motor aha xD


Haaahaa sneaky :P but wouldnt the blocks have the same amount of IAA in them? and the chemical diffuses to the part of the shoot without light? hmm what a confusing question :L
[QUOTE="nadiaaraquel;32398086"]
Original post by Phenylethylamine_
Yup, I got that for the myelin sheath and the centre was the axon. Umm, I wrote something along the lines that increase in heart rate increases oxygen uptake in blood because more impulses are sent from the medulla to the intercoastal muscles and diaphragm causing them to contract, inhaling in more air [i.e. greater oxygen uptake] I.e. signals sent from the inspiratory centre in the ventilation centres in the medulla.

No idea if that's right though!! :s-smilie:[/QUOT

I wrote something similar but also mentioned the stoke volume and loads of other nonsense haha. That was one of the few questions that were actually tricky I find.


what did you say about how the
membrane of a cell or an axon are "suited" to conduct and impulse? (something along those lines)


I out that it is normally impermeable to the ions so their movement across the membrane can be controlled by the K+/Na+ pump and the K+ channels, allowing a resting potential to be set up. Thennn when an impulse is propagated, the voltage gated channels are important.



WHY WAS THERE NOTHING ON RESPIRATION!?!?!?

I learnt all those fcuking reactions and krebs for nothing. GAHH.
Original post by bertstare
oh yeah for the 3 marker on how to tell breathing rate and tidal vol from a spirometer, what did you guys say?

i said height of peaks for tidal vol, number of peaks per min for rate, didnt know what else to right though

and for the one about how EPO is switched off, i talked about negative feedback etc?


anyone?
Original post by VetApplicant2011
I said he sprinted for the last 40 minutes and the negative feedback mechansism couldnt keep up ahah *facepalm*


Haha, yup, I wrote that too, that runner A may have been sprinting. I think knowing edexcel, i.e. stating the obvious, it might be correct :wink: I mean it did say 'suggest', so I'm thinking something obvious and simple for that question. Because if you put it in a real life, it's true one runner in a marathon's temperature might be higher overall than the other runner.
Original post by VetApplicant2011
nahh got the first bit, it was the athletes one I meant.. I realised when we came out that it was because he had lost more sweat than the other stable dude, so he must have got dehydrated and couldnt sweat anymore, meaning his negative feedback mechanisms broke.. ah well


Yeah I said that because he had lost more sweat (more water) he could have become dehydrated so sweat production was inhibited was inhibited. And I also mentioned that after the high critical temperature the mechanisms that keep the body cool start to fail , so positive feedback kicks in speeding up reactions and causing even more heat, thus his temp was out of control etc...
[QUOTE="nadiaaraquel;32398086"]
Original post by Phenylethylamine_
Yup, I got that for the myelin sheath and the centre was the axon. Umm, I wrote something along the lines that increase in heart rate increases oxygen uptake in blood because more impulses are sent from the medulla to the intercoastal muscles and diaphragm causing them to contract, inhaling in more air [i.e. greater oxygen uptake] I.e. signals sent from the inspiratory centre in the ventilation centres in the medulla.

No idea if that's right though!! :s-smilie:[/QUOT

I wrote something similar but also mentioned the stoke volume and loads of other nonsense haha. That was one of the few questions that were actually tricky I find.


what did you say about how the
membrane of a cell or an axon are "suited" to conduct and impulse? (something along those lines)




Q) Describe how the structure of axon cell membrane aids with conducting an impulse. (3)

i put:
- Has Na/K pump, which uses ATP to actively pump ions against conc gradient.
- Has voltage-gated Na and K ion channels, allows them ions to be permeable across cell membrane (otherwide ions cann't diffuse through lipid bilayer).
- continuous, hence Na ions can diffuse sideways and carrying the impulse along, like a mexican wave (Yes i did say like a mexican wave cuz im a ****ing retard)

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