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AQA BIOL5 ~ 17th June 2013 ~ A2 Biology

Reply 3380

F1's Finest

21

I swear, this exam has taken it's toll on me. Can't wait till the time is up and the invigilator says your time is up.

Reply 3381

Starlight94

What's the difference between a gene marker and a dna probe? :/

Reply 3382

YWArtist

Original post by master y

what do you mean ?

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

The first 75marks are straight forward if you know your content of biol 5 and a lil synoptic knowledge
I am aiming for 80/100, I need an A*, got full ums in the isa, but dropped 20ums in biol4, therefor can only drop 10ums in this

Reply 3383

rm.xo

I have 2 essays that I'm stuck on. The main one is pathways of synthesising carbohydrates from co2 anyone got any ideas?

I get co2 is made into carbs in the Calvin cycle. But what else could you put in this essay?

Reply 3384

Spellstheend

For making ATP from phosphocreatine, is that substrate level phosphorylation?

Reply 3385

medlou

Where does ATPase play a part in muscle contraction? I get so confused with the role of ATP here, Ive already asked a few times a thought I got my head around it but I keep confusing myself!

Reply 3386

F1's Finest

21

Original post by rm.xo

I have 2 essays that I'm stuck on. The main one is pathways of synthesising carbohydrates from co2 anyone got any ideas?

I get co2 is made into carbs in the Calvin cycle. But what else could you put in this essay?

Thats an extremely narrow essay title, they won't ask it.

Reply 3387

Dinomouse

My favourite enzyme is acetylcholinesterase. Like amylase, it just rolls off the tongue.

Reply 3388

F1's Finest

21

Original post by Spellstheend

For making ATP from phosphocreatine, is that substrate level phosphorylation?

Yes, because it's the direct linking of Pi and ADP

Reply 3389

jessica_anne_clu

2

Original post by medlou

Where does ATPase play a part in muscle contraction? I get so confused with the role of ATP here, Ive already asked a few times a thought I got my head around it but I keep confusing myself!

I'm not completely sure but isn't ATP required to allow the myosin heads to detach from the actin's myosin head binding site and return to it's original position? :smile:

Reply 3390

username929724

2

Guys... there is a mistake in the specimen paper mark scheme right??

Question 5 part a i :smile:

Reply 3391

rm.xo

Original post by James A

Thats an extremely narrow essay title, they won't ask it.

Ok good. I saw it and freaked out. I didn't know how to write 25 marks worth of points on that title.

Reply 3392

DrewYouTwo

Original post by stoppy123

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

Goody just what I thrive on. :biggrin:

quuuuestionnns

Without calcium ions their is no depolarisation of the sarcolema. Therefore calcium does not flood into the muscle fibres by diffusion. They do not bind with tropomuosin, meaning the binding sites on actin are not exposed and cross-bridge cannot form. This means muscles cannot contract and she will not be able to contract her diaphragm.

Ooh this is hard. Cause of cancer innit? Cause the gene might be inserted into different loci and effect the prof oncogenes. Also their might be an immune response to the vector.

ethical issues around (I presume embryonic) stem cells ugh they involve sesrtuction of embros and some people believe life begins at conception?

Difference between two types of neurotransmitter : acetylcholine and neuroadrenaline - former parasym, latter symp.

hydrolysis of ATP gives myosin heads energy to be cocked and slide past each other. Without enzyme ATP cannot be hydrolysed meaning filaments cannot slide past

Environmentalists - worry about superweeds and cross-pollination of crops with wild plants

Anti globalisation people - object to further enroavhment on small farmers by large corporations with patents on gene technologies

tRNA is only 60 or so nucleotides long, mRNA much longer
tRNA has tertiary strucure and h-bonds, mRNA doesn't

Baroreceptors

Reply 3393

helpme456

Original post by James A

Yes, because it's the direct linking of Pi and ADP

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?

Any idea mate?

Reply 3394

Anjna

9

Original post by medlou

Where does ATPase play a part in muscle contraction? I get so confused with the role of ATP here, Ive already asked a few times a thought I got my head around it but I keep confusing myself!

ATPase breaks down ATP releasing energy. and this energy is used to break actin - myosin cross bridge and so the myosin head detaches and returns to it's original position and attaches further along the actin filament resulting in muscle contraction (hence its called sliding filament theory)

Reply 3395

Chqr

1

Eurgh I wish the Synoptic Essay was a Unit 7 exam. Such a big concern for me.

Reply 3396

s24a

6

i would just like to point out that for people who are desperately worried about the essay, you could miss it out and still get an A. The grade boundaries so far are evidence of this.

Reply 3397

Zazuwaved

10

Original post by Anjna

ATPase breaks down ATP releasing energy. and this energy is used to break actin - myosin cross bridge and so the myosin head detaches and returns to it's original position and attaches further along the actin filament resulting in muscle contraction (hence its called sliding filament theory)

Sorry to interrupt, but there's a bit of confusion that I have the the role of Calcium ions in muscle contraction in the specimen paper, it says the Ca2+ activates ATPase, I thought it just removed the inhibitory tropomyosin from the actin-myosin binding site?

Thanks :biggrin:

Reply 3398

Starlight94

Does anyone have any notes on what we need to know about the eye? Or able to sum it up in bullet points please? :smile:

Would be really really helpful :smile:

Thanks

Reply 3399

rm.xo

Original post by medlou

Where does ATPase play a part in muscle contraction? I get so confused with the role of ATP here, Ive already asked a few times a thought I got my head around it but I keep confusing myself!

ATPase catalyses the decomposition of ATP to ADP + Pi releasing energy. This energy is used to change the orientation of the myosin head. By doing so, the actin filament is pulled along (sliding filament theory). When ADP + Pi rejoin to form ATP this ATP is bound to the myosin head, causing it to detach from the actin filament and 're-cock' its head back into its origional position.

AQA BIOL5 ~ 17th June 2013 ~ A2 Biology

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