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

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Original post by Naima100
I thought it was really obvious too :/ how can you have 2 motor neurones?!


Nahhh nah guys your all RIGHT!!! There was only one motor neurone, the other was a relay.

But I read tooo much into the question, and thought it wanted you to cross a box for every LETTER, (A,B,C,D) so I put that two were motor neurones :frown: Then wrote a little note to the examiner saying "I know this is a relay neuron, but there isnt an option forit :smile: "

Hopefully they will take pity on me xD I cant afford to lose any easy marks when Ive already lost a loaddd for the hard ones aha
Original post by VetApplicant2011
Nahhh nah guys your all RIGHT!!! There was only one motor neurone, the other was a relay.

But I read tooo much into the question, and thought it wanted you to cross a box for every LETTER, (A,B,C,D) so I put that two were motor neurones :frown: Then wrote a little note to the examiner saying "I know this is a relay neuron, but there isnt an option forit :smile: "

Hopefully they will take pity on me xD I cant afford to lose any easy marks when Ive already lost a loaddd for the hard ones aha


LOL!
The very last question was a little bit awkward for me. The one about the boy with the myostatin mutation? Originally, I used a Punnett Square, but then I noticed that the article said that the mother had the mutation (and more importantly, said nothing about the father) and the question asked, "Suggest how the boy could have obtained this mutation. Use a genetic diagram in your answer." Also, the boy had extra strength to a great extent to his mother, who had one mutation.

This says to me that the boy had two mutations in both alleles - simply because his father couldn't have had any mutations if he had normal strength and atrophy. So, instead of using a Punnett Square, I just made up a DNA gene coding for the "myostatin gene". Then, I showed a mutation occuring in the gene that "might have coded for a stop codon, resulting in the myostatin produced not working efficiently, or an incorrect amino acid being added to the chain which also changes how the protein works".

I was sure that the Punnett Square was wrong, because if the Mother had Mm (I used M's - I see that's been a topic of debate in this thread :biggrin:) and had the strength but the Father didn't, he MUST have had MM. I don't know if anyone else clocked this or if I'm ridiculously wrong...
Original post by Ayostunner
Doesnt the mother have to be a carrier right? and shouldnt he have a homozygous dominant to get the condition or is it a recessive condtion?


If it was recessive i completely effed that up then :frown:


Narppp because if it was a dominiant gene that caused it then anybody who had the gene would have the symptoms.. in order for someone to be a carrier they must have a doiminant normal gene plus a recessive mutant gene :smile: You may still get a few for actually drawing the grid and stuff though :smile:
[QUOTE="Samia99;32400812"]
Original post by InItToWinItGetIt?
I put capillaries. And shoot went to the right. They were soooooooo cheeky switching the agar blocks around.



I thought abt capillaries too ... But read the article line again it said heart has to pump thru smthng so artereies are the first ones to take blood Away from heart ryt?

Anyways ....
Wht bout axon structure? That one definitly suckd 4 me!
And for first one? Labellings?



The answer was arterioles.. small arteries :smile:
Original post by Jammers123
Did anyone else put equation for ventilation rate as ventilation rate=breathing rate x tidal volume?


yupyup
Original post by VetApplicant2011
The answer was arterioles.. small arteries :smile:


Why wouldn't capillaries count? :s-smilie:
Original post by mobius323
T/B] have had MM. I don't know if anyone else clocked this or if I'm ridiculously wrong...


Hey! I put something along those lines too. Since it gave space for you to JUSTIFY your answer and DID NOT state the father was a carrier and DID state the mother has a family history of mutations; they SHOULD give marks accordingly!

Original post by High As A Kite

for the last Q i said the Father WASNT a carrier... so i got Mm MM -> Mm Mm MM MM... But i stated he wasnt a carrier and said since the mother has a history of mutations, then the sons genes mutated and he ended up with the disease anyway... Since it didnt state the father was a carrier and gave space for explanation, would i get marks??
Ok some of the answers on here might be changing my opinions on the exam slightly :frown:. I think it went well, but i didnt go into as much detail as some of the answers on here :emo:
Original post by shanshine
for the habirtuation one
i wrote
the vesicle is discharged into the cleft and doesnt have enough time to resynthesize so no neurotransmitter realsed and therefore no action potential on post synaptic membrane
is that right~?? do you think i will get any marks for it?


not sure that you would get the marks for that.. its because the calcium ion channels become less sensitive to depolarisation so there is less chance of neurotransmitter release :smile:
Been stalking this forum for a while and just have to say this exam was annoying~
- Nothing about the brain
- Nothing about Parkinson's disease and L-Dopa
- A stupid question about spirometer use
- Pupil reflex? Anyone? no? Nowhere to be seen

Sooo annoyed - through reading through this forum, I've seen I've made little mistakes here and there but they all add up xS GAH
Original post by InItToWinItGetIt?
Why wouldn't capillaries count? :s-smilie:


The question said 'suggest' so I think anything except artery and vein counts i.e capillary, arterioles, venules
Original post by VetApplicant2011
Narppp because if it was a dominiant gene that caused it then anybody who had the gene would have the symptoms.. in order for someone to be a carrier they must have a doiminant normal gene plus a recessive mutant gene :smile: You may still get a few for actually drawing the grid and stuff though :smile:


arrgh :frown:
bad times ...

someone else told me its got nothing to do with punnet squares if thats what its called

apparently its a mutation which can only occur by a change in base sequence via addition, deletion or substitution and the person wrote about that and drew a crossing over diagram and an independent assortment to show how the mixture of the parents alleles ....

now im really worried
Original post by imaam
They should be because the paper wasn't as hard as jan 2011 and wasn't as easy as june 2010 (in my opinion) so grade boundaries should be in the middle of these 2 exams.

Plus the reason why jan 2011 grade boundaries were quite high (64 for an A*) was because most people resat that exam (from june 2010) and in the exam we done most people done it for the first time...


High? 64/90 = high?! Haha thats still pretty low dude! Compared to what it should be .. 81/90 for 90%.. 64 gives you sheeeeet loads of leeway to make mistakes.

Saying this, I still hope they are very very low, so i can actually get a half decent grade aha xD
Original post by sheep_go_baa
I said that body cells are destroyed and remade eventually so the new gene would be destroyed too...?


Ooh yesh forgot about this one, yeah I put that too, that when cells are regenerated they will have the DNA of the original organism?

What did eeveryone else put?
Original post by sheep_go_baa
The question said 'suggest' so I think anything except artery and vein counts i.e capillary, arterioles, venules


Yeah I'm pretty sure any ''small vessel'' would count.
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Avatar for Samia99
Samia99
Original post by Ayostunner
arrgh :frown:
bad times ...

someone else told me its got nothing to do with punnet squares if thats what its called

apparently its a mutation which can only occur by a change in base sequence via addition, deletion or substitution and the person wrote about that and drew a crossing over diagram and an independent assortment to show how the mixture of the parents alleles ....

now im really worried


Yea i drew a Punnet Square too!
To show the cross ... It was heterogenous Mothr nd fathr ..
So ratio was 1 Homozyous Dominant, 2 Carriers nd 1 recessive [being the boy who got the mutation which was lacking the growth-inhibitor myostatin]

Lol i'm pretty sure abt this coz this was one of the sample Q of article sm1n posted earlier ...! :p:p
(edited 12 years ago)
Original post by bertstare
do you know roughly what you need out of 90 for it to go up to 120ums


I got 120 UMS in January, and Im pretty sure I got like 3 questions completely wrong (those monoclonal antibody things stick in my mind), plus a few silly mistakes I guess.

Buttt then again I think that paper was a lot harder than this one, so I think the marks needed for 120 UMS in this will be higher?
Original post by High As A Kite
Hey! I put something along those lines too. Since it gave space for you to JUSTIFY your answer and DID NOT state the father was a carrier and DID state the mother has a family history of mutations; they SHOULD give marks accordingly!


I just thought it was asking more about how the mutation occured. It didn't say anything about the father, so I assumed he was MM. It said the mother had "a" mutation, so I assumed she was Mm. The article said that the boy "had no myostatin at all", so he must have been mm. After doing the Punnett Square (and from past experience), with the genotypes of his parents this way, the boy getting mm was impossible.
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Avatar for Naima100
Naima100
Original post by Samia99
Yea i drew a Punnet Square too!
To show the cross ... It was heterogenous Mothr nd fathr ..
So ratio was 1 Homozyous Dominant, 2 Carriers nd 1 recessive [being the boy who got the mutation which was lacking the growth-inhibitor myostatin]

Lol i'm pretty sure abt this coz this was one of the sample Q of article sm1n posted earlier ...! :p:p


that makes sense cause they didn't mention about the father so we can interpret it either way. plus it was a suggest question so I think both the punnet square and independent assortment can work. atleast I hope, was it a QWC question btw? cause I DID not use proper grammar, kind of rambled lol.

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