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AQA BIOL5 ~ 17th June 2013 ~ A2 Biology

Oh that;s terrible! Did you do okay at gcse though?

I did additional science, so my A*s in chemistry and physics brought my high C in biology up to an overall GCSE grade A somehow, but biology was my favourite until the last year when we had no teacher. Thanks for asking though! :tongue:

I managed to get a high B at as level because my biology teachers at college are amazing I think, so I'm happy! Just hate reviewing GCSE content haha :smile:

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Reply 81

nyans

Original post by master y

Oh sorry, i meant actual written out ones! Thanks anyway :smile:

Hey, Here is some bullet points with some essay ques. I have also got full essay written but they are in desktop. Will post tomo if you want.

synopticessayplans.pdf158.9KB

Reply 82

king101

3

Really need some help on this.

Okay so this is what I understand from the NT text book;

Apply pressure on Pacinian Corpuscle= causes a change in the shape of the Pacinian Corpuscle=sensory neurone membrane stretching=stretch mediated sodium channels widen=allow sodium ions to diffuse in= local depolarisation. Greater the depolarisation will eventually reach a threshold where a generator potential is produced and hence an action potential is produced.

This is what the NT text book says..right my confusion whats the different between Generator Potential and Action Potential? According to the text book it says both are nerve impulse?>

if this is so then how come in the axon where it continually has to make a action potential why? Hasn't the generator potential already produced an impulse?

Reply 83

nyans

Original post by king101

Really need some help on this.

Okay so this is what I understand from the NT text book;

Apply pressure on Pacinian Corpuscle= causes a change in the shape of the Pacinian Corpuscle=sensory neurone membrane stretching=stretch mediated sodium channels widen=allow sodium ions to diffuse in= local depolarisation. Greater the depolarisation will eventually reach a threshold where a generator potential is produced and hence an action potential is produced.

This is what the NT text book says..right my confusion whats the different between Generator Potential and Action Potential? According to the text book it says both are nerve impulse?>

if this is so then how come in the axon where it continually has to make a action potential why? Hasn't the generator potential already produced an impulse?

Hope this will help:

A generator potential is a graded response to a stimulus and if it becomes large enough it produces an action potential. These generator potentials "add" together which is called summation and allows an action potential to fire.

An action potential is not graded and is all or nothing. Also an action potential travels along a nerve fibre where as a generator potential does not it is localised change is the concentration of charges.

http://www.biologymad.com/nervoussystem/nerveimpulses.htm

Reply 84

dizzy17

how do you use the results of the standard error test to accept or reject the null hypothesis, and determine the probability that the results are due to chance?

Reply 85

Duggan

Original post by feelinginfinite

I'm so glad to have found a thread for this already! I wanted to get a head start and be more organised in revision :smile:

I've done the ISA (diabetes) already and got 50/60 ums (YAY!), so I can focus on BIOL5 content now

The way I'm revising:
- At the weekend, I'm going over the topics in the NT book that I've done through the week in class; typing them up in brief notes to look over quickly every 2 weeks
- Reading ahead on 2 sub topics each weekend (I find it easier to know what my teachers are going on about when I do this) :tongue:

My teachers said we should be finished all BIOL5 content by the end of April, where I'll be revising by:
- Going through each topic in NT, then the same topic in CGP, looking over brief notes I've made each weekend, watching a youtube video on each topic (there's some great channels- I think "youtube/khanacademy" really helped me with BIOL4)
- After doing it for every topic, do a past paper, mark it, see where I went wrong/my worst topic
- Re-revise my worst topics, do those questions again, and repeat this for all of the past papers

Personally, I'm struggling with sections 9 and 10 already since I didn't have a set GCSE teacher so don't know the basic content on the nervous system. I've borrowed a GCSE Science book from the library so hopefully that'll help. Are any of you struggling with topics? :smile:

So far I've done sections: 9 (bad at), 10 (bad at), 12 (love it), 13 (like it)

Hi there im doing this isa next week could you give me any tips please they are much needed :smile:

Reply 86

Blombard

Original post by sechdent8

hey guys, i have my empa coming up in early march :/ i didnt do too well last year on the AS empa and i really want to do well on this empa. Does anyone have any advice or material (books, websites etc.) they are using to prepare? How are you guys preparing?

whats your empa title?

Reply 87

darryalar

11

Any idea on this question:

Which enzyme's better, one that works at a specific temperature or one that works in many and explain why?

Reply 88

dizzy17

Original post by darryalar

Any idea on this question:

Which enzyme's better, one that works at a specific temperature or one that works in many and explain why?

err one that works in many cos it can be used in different processes that require different temperatures, so is more versatile?

Reply 89

sechdent8

7

Hey guys, i know this is BIOL4 stuff but there is a chance i may have to resit so i'm trying to get this stuff done now.

I have some questions about a number of factors that affect the rate of photosynthesis. I am failing to understand how temperature, pH, light intensity and carbon dioxide concentration will lead to an increase in the amount of oxygen produced (we are using the number of bubbles as a measure of the amount of oxygen released). For light intensity is this the case: Greater light intensity will lead to more electrons in chlorophyll molecules being excited and taken up by electron carriers. To account for the loss of electrons from chlorophyll molecules more photolysis occurs meaning the electrons are replaced and more oxygen is released as a product of photolysis? As for temperature i don't understand how an increase in temperature will need to more oxygen being produced because in photosynthesis only carrier proteins and enzymes are used. Carrier proteins and enzymes are used in the light independent stage and no oxygen is produced here and even in the light dependent stage an increase in temperature would lead to more oxygen being produced. I have the same issue for carbon dioxide concentration, CO2 is only used in the light independent stage, so how would it lead to more oxygen being produced since oxygen is not involved in the light independent stage? And the same question for pH.

Reply 90

Rachieee123

I have a question ;

"how do you know an aelle is controlled by a single gene?"

Like if they give you a set of results what would you look for?

Thanks very much! xx

Reply 91

master y

12

Original post by Rachieee123

I have a question ;

"how do you know an aelle is controlled by a single gene?"

Like if they give you a set of results what would you look for?

Thanks very much! xx

can u give an example question please?

Reply 92

dizzy17

I've got some questions that I've been set as hmwk that i'm stuck on... on food labels with 100g per serving, the total of all the individual components ( fat, proteins etc) can add up to more or less than 100g. why is this, I really don't understand it!