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

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Reply 2080

Original post by InItToWinItGetIt?

Could anyone help me with this question:

Bungaratoxin can be isolated from the venom of the Prugasti krait. In minute amounts, it can cause paralysis of the diaphragm and intercostal muscles by its effects at synapses. Suggest how bungaratoxin causes these effects.

MS answer:
1. ref to prevention of release of neurotransmitter from presynaptic membrane;
2. similar shape (to neurotransmitter);
3. {binds / blocks / fits into} receptor on postsynaptic membrane;
4. ref to {sodium ion / Na+ / cation} channels / hyperpolarisation / permanent depolarisation} of postsynaptic membrane;
5. no nerve impulses / action potentials / continuous action potential / eq;
6. inhibits acetylcholinesterase / breakdown enzyme / (bungarotoxin) not affected by breakdown enzyme;

I don't get it as if the Bungaratoxin has a similar shape to the neurotransmitter, then it would do the same effect as that neurotransmitter, or no?

I put that it's complementary to the the neurotransmitter, so binds to it and prevents as many binding to receptors on the post-synaptic membrane.

it could be an inhibitory neurotransmitter the same shape as the neurotransmitter? So it prevents the impulse being transmitted to the post synaptic membrane? :smile:

Reply 2081

High As A Kite

Do you guys know the process of alcoholic and lactate fermentation?

do we need to know it? (to do with regeneration of NAD+)

p.s im not looking for you to explain it, dw !

Reply 2082

chemdweeb1234

Original post by High As A Kite

Do you guys know the process of alcoholic and lactate fermentation?

do we need to know it? (to do with regeneration of NAD+)

p.s im not looking for you to explain it, dw !

lactate, yes
alcohol, no

Reply 2083

High As A Kite

Original post by chemdweeb1234

lactate, yes
alcohol, no

thanks for the reply. :smile:

i'm guessing thats from the spec, right? anything else edexcel like to fill our textbook with which we dont actually need to know?

Reply 2084

AGM

Original post by High As A Kite

Do you guys know the process of alcoholic and lactate fermentation?

do we need to know it? (to do with regeneration of NAD+)

p.s im not looking for you to explain it, dw !

The only thing I'm aware we need to know to do with lactate is anaerobic respiration.

And that's just that as you say, converting pyruvate to lactate regenerates NAD to then be used again in glycolysis.

Reply 2085

AGM

Original post by claire4095

it could be an inhibitory neurotransmitter the same shape as the neurotransmitter? So it prevents the impulse being transmitted to the post synaptic membrane? :smile:

I guess it would work in the same way as MDMA... except it blocks the post synaptic membrane, not the presynaptic membrane.

Reply 2086

High As A Kite

chemiosmotic theory of ATP?

is that needed?

Reply 2087

xrdrctftvygy

Original post by High As A Kite

chemiosmotic theory of ATP?

is that needed?

yep, thats the huge bit on oxidative phosphorylation under the respiration topic.

Reply 2088

AGM

Original post by High As A Kite

chemiosmotic theory of ATP?

is that needed?

If you mean chemiosmosis... then yes; you need to know it as part of oxidative phosphorylation which is part of aerobic respiration.

Reply 2089

voices1

Done too much of article. i think spend next 2 days over topic 7 and 8.

Reply 2090

claire4095

Original post by AGM

I guess it would work in the same way as MDMA... except it blocks the post synaptic membrane, not the presynaptic membrane.

Does ecstacy block membranes? I thought it just blocked/binded to the transporter molecule that takes the neurotansmitter back up to the presynaptic membrane? or reversed the effects of the molecule and brings more serotonin in the synaptic cleft? :/ confusedd :frown:

xx lol

Reply 2091

AGM

Original post by claire4095

xx lol

All I have down is that it inhibits the re-uptake mechanism due to the fact it has a similar shape to serotonin. I'm sure you are also right, but just in more depth :smile:

Reply 2092

claire4095

Original post by AGM

All I have down is that it inhibits the re-uptake mechanism due to the fact it has a similar shape to serotonin. I'm sure you are also right, but just in more depth :smile:

yeahh lol i think were both right :smile:

YAY! Good luck x

Reply 2093

darkiee

Are people nervous about this paper, I am

Reply 2094

InItToWinItGetIt?

Original post by darkiee

Are people nervous about this paper, I am

I am brickin it. And it doesn't help bio 4 went ****, this exam is do or die for me. Got two exams tmrw as well, which ruins the revision for this one. :mad:

Well one of them is General studies so it technically doesn't count, but its a waste of 2-3 hours revision time.

(edited 12 years ago)

Reply 2095

darkiee

Original post by InItToWinItGetIt?

I am brickin it. And it doesn't help bio 4 went ****, this exam is do or die for me. Got two exams tmrw as well, which ruins the revision for this one. :mad:

Well one of them is General studies so it technically doesn't count, but its a waste of 2-3 hours revision time.

Its a morning paper as well, wished it was afternoon so bad

Reply 2096

InItToWinItGetIt?

Original post by darkiee

Its a morning paper as well, wished it was afternoon so bad

Not too bothered about that as I seem to do better on morning papers for some reason. I seem to get really tired out by the afternoon when exam's are on. But yeah I know what you mean, lot more revision time.

Reply 2097

bashx

they dont tell you in the case study quesions (page blah blah pargraph blah blah) do they?

Reply 2098

darkiee

i hope things to do with IAA doesnt come out at all and auxin, I want phytochrome but nor auxin or iaa

(edited 12 years ago)

Reply 2099

Spain'93

Can someone please explain to me the difference between Chemiosmosis and Oxidative Phosphorylation? I seem to have all of the information under Oxidative Phosphorylation :frown: