[James A]

(Original post by jessplease)
I will definitely be saying extremelyyyyyyy happy if inorganic ions come up, PLEASE AQA, it hasn't come up before has it? Although if examiners were hinting at ecology, think it could be the mean temperatures increasing one of just transfers in general through ecosystem!

I don't see why they would put a 'transfers through ecosystem' question. That's too specific to unit 4.

The synoptic essay questions are designed to allow students to incorporate various topics throughout the a-level syllabus from unit 1, 2, 4 and 5.


With the transfers of energy through ecosystems question, there's not a lot to talk about. But it's good to know some points, in case it does come up by chance.

[thenumber2goose]

(Original post by asaaal)
the past papers for this unit are so minimal :| !

has anyone got any sites where i could get some exam style questions with answers?

http://www.aqa.org.uk/qualifications...6416-materials

These are old spec questions. Some of the questions in the unit 2 and the unit 4 papers. You'll just have to look through and see if they seem familiar

[tfdes]

(Original post by asaaal)
dont meet to intrude but...
where are people getting the idea that inorganic ions will come up?

I think it's looking back at past papers and trying to work out what topics have not yet been picked on, which does contain a lot of information to write a 25 mark essay on .. maybe ..

[Sam-8]

(Original post by jessplease)
I will definitely be saying extremelyyyyyyy happy if inorganic ions come up, PLEASE AQA, it hasn't come up before has it? Although if examiners were hinting at ecology, think it could be the mean temperatures increasing one of just transfers in general through ecosystem!

how have examiners influenced it would be ecology??

[tfdes]

(Original post by jessplease)
I will definitely be saying extremelyyyyyyy happy if inorganic ions come up, PLEASE AQA, it hasn't come up before has it? Although if examiners were hinting at ecology, think it could be the mean temperatures increasing one of just transfers in general through ecosystem!

Examiners hinting?? Temperature transfer through ecosystems.. ? HUH?

[whc23]

(Original post by lilcherrydrop)
So are you comparing the partially digested pieces (any/all combinations) with the completely digested DNA quantity, the 10kb?

So on the gel electrophoresis - for complete digestion would you only have 3 DNA fragments (the 5kb, 4kb and the 1kb) regardless of HOW many plasmids/DNA you cut up - that would make sense as to why you have more than the original DNA on the gel - because for partial digestion you may have 9kb, 5kb, 1kb etc.... Is this the case? Thanks!

Yes, one lane of the gel with the completely digested DNA would have 3 fragments (5kb, 4kb and 1kb) while another lane with an incomplete digest might have 9Kb as well as the 5kb, 4kb and 1kb fragments.

http://cambridgeacademic.blogspot.co.uk/

[umair.khan]

Hey could someone just clarify this with me please. I know it sounds a bit stupid

the uptake of glucose by sodium-glucose transport, does it require ATP? and where does this process take place

Thanks

[lilcherrydrop]

(Original post by umair.khan)
Hey could someone just clarify this with me please. I know it sounds a bit stupid

the uptake of glucose by sodium-glucose transport, does it require ATP? and where does this process take place

Thanks

It does - but indirectly. ATP is used in co-transpot to set up a conc. gradient for Na+ so that it is moved against it's concentration. Then Na+ can diffuse down it's concentration gradient, coupling - bringing glucose with it, this way, glucose is moved against it's conc. gradient! I think it happens in the lumen of the small intestine and epithelial cells but you might want to check for details.

[dc2012]

(Original post by JackMitchell29)
Does anyone have a decent plan for both an inorganic ions essay and an essay on ATP? Thanks!

yeahh ive done both of those.

with the ions one try to group them into ions used by
>microorganisms- oxidation of ammonium ions into nitrites etc
>plants- uptake of ions- allowing osmosis/ H ions in photosynthesis
>animals- sodium/potassium pump/ calcium ions/ iron ions/ H ions in respiration

for ATP do the same

>microorganisms- may require active transport of molecules across membrane( just blagging- try to relate processes)
>plants- active transport of ions- ATP used to reduce glycerate 3 phosphate
>animals- use of ATP in active transport- resting potential/ co trabsport of glucose- muscular contraction/polypeptide synthesis


Hope that helps dude

good luck!!

[lilcherrydrop]

(Original post by whc23)
Yes, one lane of the gel with the completely digested DNA would have 3 fragments (5kb, 4kb and 1kb) while another lane with an incomplete digest might have 9Kb as well as the 5kb, 4kb and 1kb fragments.

http://cambridgeacademic.blogspot.co.uk/

Okay so technically the 'more DNA than original' on refers to that on the gel - DNA ladder - rather than all the actual pieces if that makes sense!

[narnia123]

Can someone say what they would write if an essay on the role of enzymes comes up

[rss.914]

can someone explain to me why some people are colour blind? is it to do with cone cells

[dc2012]

(Original post by umair.khan)
Hey could someone just clarify this with me please. I know it sounds a bit stupid

the uptake of glucose by sodium-glucose transport, does it require ATP? and where does this process take place

Thanks

takes place in the epithelial cells of the small intestine- it does require ATP in an indirect way. sodium ions are actively transported out in doing so there is a hiigher concentrations of the ions in the lumen of the intestine they therefore travelk down their diffusion gradient into the epithelial cells annnnnddd they couple with glucose allowing maximum absorption of glucose. hope that cleared things up

[alexissocool]

(Original post by narnia123)
Can someone say what they would write if an essay on the role of enzymes comes up

Talk about unit 1 stuff - enzyme controlled reactions - lowering the activation energy. Mention effects of temperature/pH/substrate concentration of how enzymes function and thus their ability to perform their role. (Unit 1)

Digestion - lipases/proteases etc. (unit 1)

Semi conservative replication - role of DNA helicase and DNA polymerase (unit 2)

Photosynthesis - Rubisco effects on light-independent reaction. (Unit 4)

ATPase - the enzyme involved in muscle contraction what it does and what its role is in performing muscle contraction. (Unit 5)

Acetylcholinesterase - to break down acetylcholine into acetyl and ethanoic acid. Why is this important? (Unit 5)

Talk about the role of DNA helicase and RNA polymerase in Transcription. (unit 5)

Talk about reverse transcriptase/restriction endonucleases/DNA ligase with in vivo gene cloning. (Unit 5).

lilcherrydrop mentioned a good point as well; the role of enzymes in the second messenger model - e.g. enzyme converts ATP to cyclic AMP. Cyclic AMP then activates an enzyme which converts glycogen into glucose. (Unit 5)
Just some ideas here off the top of my head.

[lilcherrydrop]

(Original post by narnia123)
Can someone say what they would write if an essay on the role of enzymes comes up

U1: structure of proteins - primary structure etc.
Enzymes in catalysing reactions by active sites forming enz.- substrate complexes. And how hey lower Ea by distorting bonds and putting startin on them.
Importance of digestive enzymes.

U2:

U4: BuBisCo in catalysing addition of RuBP to CO2 .. elaborate on Calvin cycle and how enzymes important for intial formation of a Glycerate-3-phosphate etc. - so for making glucose overall!
U5: role of ATPase in mucle contraction, enzymes in conversion of glycogen to glucose in 2nd messenger model...

That's all I can think of for enzymes really. Protein essay would easier because enzymes are proteins!

[umair.khan]

(Original post by dc2012)
takes place in the epithelial cells of the small intestine- it does require ATP in an indirect way. sodium ions are actively transported out in doing so there is a hiigher concentrations of the ions in the lumen of the intestine they therefore travelk down their diffusion gradient into the epithelial cells annnnnddd they couple with glucose allowing maximum absorption of glucose. hope that cleared things up

ahh right, thanks alot!!

[lilcherrydrop]

Any ideas for negative/positive feedback from U2 AND U4?

Does stomata closing count as negative feedback to prevent further water loss? Lul

[alexissocool]

(Original post by lilcherrydrop)
Any ideas for negative/positive feedback from U2 AND U4?

Does stomata closing count as negative feedback to prevent further water loss? Lul

I really hope we don't get a feedback question. I can only really relate it to unit 5 :/

[stephie.u3]

guys i havent even started revision...where do i begin?? help please, i'm really struggling with exams this summer, not in the right frame of mind

[handsome7654]

(Original post by leeandrewarmstrong)
I've made some BIOL5 notes using past paper (legacy) mark schemes. Enjoy

I'm working on an extended version which will contain some condensed notes from the Nelson Thornes textbook.

Mate, I think I love you!