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AQA BIOL5 ~ 17th June 2013 ~ A2 Biology

Reply 3360

rommy123

Original post by Anjna

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

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

Thankyou

Reply 3361

EllieSp

Original post by 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

thats right! :biggrin:

Reply 3362

edward28

1

Original post by EllieSp

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:

Thank you! :biggrin:

Reply 3363

Lyont

Original post by Anjna

why do they prefer damp conditions?

Woodlice are crustaceans and need moisture to feed and breathe. Their shells are porous and by the process of diffusion they absorb water and oxygen and excrete waste in the form of gas (ammonia). They have two uropod at the rear and this is also used to absorb water when they are against moist surfaces in damp places. Woodlice lose water through their shells quickly and will dry out and die when there is no moisture because they have a large surface area to volume ratio and loose water quickly by diffusion.

Reply 3364

LegendX

15

Original post by tn234

are there any more examples? :smile:

Hi, please find attached another model essay answer. Again, this would score full marks with ease. Is there any specific essay titles you need the model answer to?

In restriction enzymes, is it that

-the shape of the DNA cut is complementary to the shape of the active site
OR
- the bases of the DNA are complementary to the active site bases

Or neither :P

Reply 3366

YWArtist

Original post by ActaNonVerba

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

Lol in the 3 past papers the only synoptic questions have been the last HSW question so chill!

Reply 3367

master y

12

Original post by YWArtist

Lol in the 3 past papers the only synoptic questions have been the last HSW question so chill!

what do you mean ?

Also , what marks have people been getting on past papers, and what grade are u aiming for??

Reply 3368

Lyont

Original post by Mesutozil

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

why is this important?

It ensures that the brain isn't going to be constantly bombarded with impulses :smile:

Reply 3369

problematic

Original post by katiep93

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

Photosynthesis aspect of ATP (the breakdown of ATP by light, would require a brushup on unit 4 stuff
Glycolysis needs ATP to make pyruvates (but results in a net gain of 2 ATP)

A sentence on how ATP is produced and broken down (hydrolysis and condensation)
The general uses of ATP (this will probably be the bulk of the essay imo)

Muscle contraction
Nervous system (Na+K+ pump)
How ATP is converted to cyclic AMP for adrenalins second messenger model
A bit from AS biology for breadth (active transport of ions against conc. gradient for Root pressure)

Reply 3370

stoppy123

4

Questions to refresh your memory!

Poison X removes Ca2+ ions in muscle fibres, explain why this person will die when poisoned with Poison X(3)
The insertation of genes through gene therapy can have dangerous consequences, explain why (2)
Explain why there is ethical issues around stem cells research (2)
Describe and explain the two types of neurotransmitter (4)
Inhibitor Y inhibits ATPase in muscle cells, explain why they are unable to contract (2)
Certain pressure groups have problems with GMOs, describe and explain two of these groups (4)
tRNA is structurally different from mRNA, give 2 reasons why (2)
Name the receptors in the blood that respond to high blood pressure (1)

/20

Reply 3371

rm.xo

I am not looking forward to this exam tomorrow whatsoever :facepalm:

Reply 3372

edward28

1

Does anyone know how the relationship between oestrogen and LH positive feedback? Is it just that more oestrogen produces more LH?

Reply 3373

Starlight94

Just reposting in case anyone hasn't seen this yet, found it a very useful quiz :smile:

http://quizlet.com/11320494/learn/

Reply 3374

kingster123

can ANY1 brief resting potential and action potential and what is generator potential ??

Reply 3375

EllieSp

Original post by katiep93

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

i really hope ATP is one of the essays.
Uses of ATP
what ATP is and how much energy is released when hydrolysis occurs
ATP in active transport and definition eg, resting potential in neurones
ATP in muscle contractoin and reabsorption of calcium
ATP in photosynthesis in calvin cycle
glycolysis
ATP -> cyclic AMP in second messenger model
used in flurescence (non spec) by exciting electrons
used in active transport of products of extracellular digestion in bacteria

Also depending on the question - How it is made
Respiration aerobic anaerobic
Phosphocreatine
photosynthesis :eek4:

Reply 3376

Lyont

Original post by 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

The key thing to know about IAA is that in the shoot of the plant it encourages growth, whereas in the root it inhibits growth, it is only found in the tip of the shoot/root. So for example, if a shoot was illuminated from the right hand side, the IAA will diffuse to the left hand side of the tip causing that side to grow more and turn the plant towards the light stimulus. Where as in a root, the IAA will to the underside of the root due to gravity stimulus (or a light if it is at the soil surface) and inhibit growth on the under side, causing to grow downwards :smile:

hope this helped

Reply 3377

helpme456

http://filestore.aqa.org.uk/subjects...W-QP-JUN10.PDF

For Q6cii, how am I supposed to know it affects tumour supressor gene not proto-oncogen?

Reply 3378

DELETED ACCOUNT

15

Original post by Starlight94

Just reposting in case anyone hasn't seen this yet, found it a very useful quiz :smile:

http://quizlet.com/11320494/learn/

I've done it. It was great.! But for some reason I got the enzyme that breaks down acetylcholine wrong. Thought it was Actylcholinesterase, they kept it as cholinesterase,so they both might be acceptable I hope.

Reply 3379

helpme456

Question 9 is solid!

AQA BIOL5 ~ 17th June 2013 ~ A2 Biology

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