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

Original post by chemdweeb1234

Hmm.. they have cheekily omitted it in the green book... they have mentioned a bit on Page 180 and 181... but it the context of steroids... there is literally like one or so paragraphs on it :smile:

Yeah not much on it. Thanks for pointing it out though, I didn't notice that there was in fact something on it lol

Reply 1443

nikki_aiyana

Hey guys, in bio today we went through the first 2 and a half pages, and came up with:
translation/transcription of whole musce structure (myosin, actin etc)
genetic modification using restriction endonucleases and/or vectors
richer capillary system - more contact with the muscle, slower blood movement which gives the oxygen more time to diffuse into the muscles
bigger muscles - gene to make actin, myosin etc bigger
higher risk of heart disease - blood thicker, more viscous, more work for the heart, clot more likely to form (EPO paragraph 4)
medical trials and ethics
paragraph 5 - more red blood cells - mutation to the EPO receptor on the membrane of the cell
paragraph 7 - recombinant bacteria, AIDs, immune system => how the body responds to viruses (AAVs), risks associated with gene therapy, atherosclerosis and gene splicing
hope this help someone in here =]

Reply 1444

uEn

haha yeah that is funny, I got full ums in a retake and over 90% in unit 4, but my raw marks in unit 4 were 60/90. I was like 'that's A*? I'll have that'.

Reply 1445

Original post by uEn

haha yeah that is funny, I got full ums in a retake and over 90% in unit 4, but my raw marks in unit 4 were 60/90. I was like 'that's A*? I'll have that'.

how did you know your raw marks?

Reply 1446

Vav123

does anyone have the january 2011 paper and mark scheme? thanks

Reply 1447

tkoki1993

10

Can anyone explain oxidative phophorylation. I have a general idea of what it is and I know it happens in the inner membrane of the cristae but i'm not entirely sure of what I should write if it comes up in the exam. Thanks :biggrin:

Reply 1448

IGotAQuestion

Original post by tkoki1993

Can anyone explain oxidative phophorylation. I have a general idea of what it is and I know it happens in the inner membrane of the cristae but i'm not entirely sure of what I should write if it comes up in the exam. Thanks :biggrin:

Hi, not sure what type of answer you're looking for but......

In an ETC, electrons are passed down different energy levels - releasing energy that powers the production of ATP... this is called 'oxidative phosphorylation' because ADP is phoshphorylated in a process dependent on oxygen :colondollar:

Reply 1449

Quite nervous of this paper??

Reply 1450

Original post by medtobe

Quite nervous of this paper??

I'm well nervous. Especially about the article and what stuff they will ask on it.

Reply 1451

Original post by InItToWinItGetIt?

I'm well nervous. Especially about the article and what stuff they will ask on it.

In june 2010 paper
the equation on ECG I found it it hard, I mean is it in the syllabus?
ECG is there but do we have enough knowledge to answer that question?

Reply 1452

Original post by medtobe

In june 2010 paper
the equation on ECG I found it it hard, I mean is it in the syllabus?
ECG is there but do we have enough knowledge to answer that question?

I think it is on the syllabus but the question seems to ask to describe the effect of the ectopic beat on the heart which is relatively easy. But then an explanation for it I'm a bit stumped on.

It's a bit of a mean question though and especially as it's 5 marks! :eek:

Reply 1453

Original post by InItToWinItGetIt?

I think it is on the syllabus but the question seems to ask to describe the effect of the ectopic beat on the heart which is relatively easy. But then an explanation for it I'm a bit stumped on.

It's a bit of a mean question though and especially as it's 5 marks! :eek:

Yeah if it was 2 marks shape but 5 mark !!

But normally 65/90 = A* in edexcel bio :smile:

But just cn't get the fact how so many people lose so many marks. :confused:

Reply 1454

Original post by medtobe

Yeah if it was 2 marks shape but 5 mark !!

But normally 65/90 = A* in edexcel bio :smile:

But just cn't get the fact how so many people lose so many marks. :confused:

Let's leave well enough alone :tongue:

Have you got a link to the grade boundaries? I can't seem to find them.

Reply 1455

tkoki1993

10

Original post by IGotAQuestion

Hi, not sure what type of answer you're looking for but......

In an ETC, electrons are passed down different energy levels - releasing energy that powers the production of ATP... this is called 'oxidative phosphorylation' because ADP is phoshphorylated in a process dependent on oxygen :colondollar:

thanks thats exactly what i was looking for :smile:

Reply 1456

idiotone

hey..could someone please explain the Pfr and Pr stuff to me..? as in summarise the steps as it seems quite confusing ..

Reply 1457

Zanny17

Original post by tkoki1993

thanks thats exactly what i was looking for :smile:

You forgot the main part of oxidative phosphorylation ^^ which is oxygen acting as the terminal electron acceptor forming h20 in the process :smile:

Without O2, the electrons in the ETC can't be 'disposed' of (which is done by combining with oxygen and forming water) and so the ETC stops functioning as all the carriers are loaded with an electron - ETC stops so no ATP formation :biggrin:

Reply 1458

Zanny17

Original post by idiotone

hey..could someone please explain the Pfr and Pr stuff to me..? as in summarise the steps as it seems quite confusing ..

First you need to be aware of the reaction that takes place

RED LIGHT - Day
FAR RED LIGHT - Night
So in red light/DAY Pr is changed to Pfr
and in far red light/NIGHT Pfr is is changed to Pr

You need to be aware of two types of plants:

•

LDP (long day plants)

•

SDP (short day plants)

LDP can be referred to as SNP 'short night plants' for better understanding but do not call them this during the exam! :tongue:

•

Pfr STIMULATES flowering

•

Requires MAXIMUM hours of darkness, any longer and Pfr will be changed into Pr so no flowering.

SDP 'Long night plants'

•

Pfr INHIBITS flowering

•

requires MINIMUM length of darkness - requires enough far red light to change sufficient amount of Pfr to remove the inhibition

Remember its the length of DARKNESS that determines whether a plant flowers. This can be demonstrated by:
Placing a SDP 'long night plant' and exposing it to say 3 hours of day and 9 hours of darkness. The result is flowering. However if you distrub this single period of darkness by flashing red light (day - changes Pr to Pfr) there is NO flowering.
Therefore the conclusion is that the period of darkness is the CRITICAL FACTOR in inducing flowering.
Hope that helps! :smile:

Reply 1459