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AQA BIOL5 ~ 17th June 2013 ~ A2 Biology

Reply 3340

rommy123

what is the equation for magnification? and how do you convert the units :/ completely forgot how to do this

Reply 3341

Mesutozil

the refractory period ensures the action potentials are separated and limited in number

why is this important?

Reply 3342

Anjna

9

Original post by rommy123

what is the equation for magnification? and how do you convert the units :/ completely forgot how to do this

M = image (in mm convert to um) / actual image (um)

to convert mm to um ... mm x 1000 = um

Reply 3343

Anjna

9

Original post by Lyont

Woodlice prefer dark and damp conditions, not necessarily humid conditions :smile:

why do they prefer damp conditions?

Reply 3344

bad8oy

14

Original post by Beth_L_G

If you know everything else well enough you can get an a without even doing the essay
That's my way of cheering myself up :L

Aha yeah I was thinking that as well :tongue:

Try and get atleast 62/63+ out of 75 then only need 10/25 in the essay :biggrin:

Problem is though I have no idea what I need to get for an A overall because I don't know scores from resits

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Reply 3345

stoppy123

4

Original post by medlou

Anyone got any ideas on what to include in a "variation in living organisms" essay? Ive got:
- meiosis
-mutations; different types, what they lead to (different protein structure)
- Natural Selection and adaptation

Not sure what else to talk about..

Genetic bottlenecks, founder effects.
Speciation?
Using pest-resistant crops, reduces variation in living organisms?

Reply 3346

edward28

1

Hey I was really confused about how proto oncogenes work. I know they stimulate cell division but do they do that by producing growth factors? Or are they in the DNA and they just produce a protein that causes the cell to divide??

Reply 3347

stoppy123

4

Original post by Mesutozil

the refractory period ensures the action potentials are separated and limited in number

why is this important?

Because otherwise action potentials would all fuse together as they'd happen continually, meaning that ions would be all out of balance,

Reply 3348

YWArtist

Original post by bad8oy

Yeah definitely..Im just wondering how many marks you get for one fully developed point under scientific content.
I'm thinking I might just try to talk about 5 things in detail and then add all the stuff that there's not much to say about.

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That's my plan for each essay, come up with 5 5markers and then just chat **** around but obvs not off topic :tongue:

Reply 3349

Starlight94

In a way it's good i've resat units 2 & 4 because it's saving time of essay revision, but on the other hand my unit 5 knowledge is poor :/ starting to panic now

Reply 3350

problematic

Original post by medlou

Anyone got any ideas on what to include in a "variation in living organisms" essay? Ive got:
- meiosis
-mutations; different types, what they lead to (different protein structure)
- Natural Selection and adaptation

Not sure what else to talk about..

The reduction in variation perhaps, and how that leads to a reduction in genetic variety
The meiosis: Crossing over, recombination, random segregation. That should cover a few sentences
Variation caused by environmental factors is a big one, such as smoking, mutagenic agents, leading to the mutations etc
Genetic causes: mutations causing things like sickle cell and cystic fibrosis would be a nice touch
The bacteria shouldn't be left out (conjugation, transmission)
And plants varied to carry out their functions (different plants have different adaptations, such as drought resistant etc.)

Hope that helps

Reply 3351

DrewYouTwo

Original post by edward28

Hey I was really confused about how proto oncogenes work. I know they stimulate cell division but do they do that by producing growth factors? Or are they in the DNA and they just produce a protein that causes the cell to divide??

TheY divide only in presence of external transcription factors, which bind to them and initiate the enzymes needed for mitosis.

Oncogenes by contrast are strong independent genes who don't need no transcription factors, so they just divide because YOLO

Reply 3352

MLogan

Original post by Starlight94

In a way it's good i've resat units 2 & 4 because it's saving time of essay revision, but on the other hand my unit 5 knowledge is poor :/ starting to panic now

Same here! I think the panic mode has been turned on :|

Reply 3353

ActaNonVerba

Original post by YWArtist

What's synopsis lol

stuff not on the syllabus for this exam, so basically anything related to biology can pop up.. like the founder effect for example can be in a question in this exam

Reply 3354

katiep93

what sort of things would you include in ATP essays ? :smile:

Reply 3355

bad8oy

14

Original post by YWArtist

That's my plan for each essay, come up with 5 5markers and then just chat **** around but obvs not off topic :tongue:

Aha yeah....if the right essay comes up we should be able to get as much detail from unit 5 in because we know all that in full detail and add other units as much as we can
should be live man

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Reply 3356

Melissa.S.

Can somebody help with plant growth factors please, IAA.

So is IAA in the tip of the plant,which then diffuses down the shoot to the side with no light? So the shaded side grows more?
June 2012 question 7c really confused me.. lol

Reply 3357

Aimee18

Original post by Hellz_Bellz!

Generally the essays in the past have been about these topics:

- mutations (causes, etc)
- cycles
- energy transfer (either within organisms or within the environment)
- importance of bacteria
- causes of disease
- uses of ATP

They're generally based around that kind of thing. I have a feeling the one tomorrow is going to be about cycles, as in the Unit 4 exam nothing came up about cycles.

But cycles already came up in june 2011

Reply 3358

EllieSp

Original post by edward28

Hey I was really confused about how proto oncogenes work. I know they stimulate cell division but do they do that by producing growth factors? Or are they in the DNA and they just produce a protein that causes the cell to divide??

the produce growth factors that bind to the cell membrane and activate relay proteins in the cell that go on to activate specific genes (turn on) that need transcribing
:ahee:

Reply 3359

Starlight94

Does anyone have a revision check list? :smile:

AQA BIOL5 ~ 17th June 2013 ~ A2 Biology

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