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A2 Biology OCR June 2015 Revision Thread

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[QUOTE=edsketch;56714689]Okay, something I'm really confused about, and I'm sure I'm not alone on this one. So the Electron Transport Chain is used during Non-Cyclic Phosphorylation, where light energy excites an e- which moves along the electron carriers losing energy.
But it's also used in animals with Respiration, during Oxidative Phosphorylation? What're the differences between the two? It's so confusing!
Remember that respiration also occurs in plant cells. And the processes are similar in respiration and photosynthesis. In photophosphorylation the final electron acceptor is a chlorophyll molecule/NADP while in oxidative phosphorylation its oxygen. That's all I can think of.
Original post by domcandrews
Lol as if some guy on here was supposedly revising the f215 topics for the exam tomorrow!! thats jokes


it's not funny haha :frown: think i might be in trouble
Original post by hajs
Thats what i thought. The answer however is...
either
deaminationof amino acids / removal of NH2 from amino acids ;
pyruvate/ carbon skeleton / AW ;
triosephosphate / TP ;condensation/ increasing number of carbon atoms ;
or
breakdownof, lipid / triglyceride ;
glycerol;
triosephosphate / TP ;
condensation/ increasing number of carbon atoms ; max3


What I said is what happens. What they said is true but a very simplified version.

Amino acids are bled into the krebs cycle via a few reactions, one being deamination to create a carbon skeleton. it then goes to pyruvate and does reverse glycolysis (one part of glycolysis is triosephospahte)

TP + TP = Hexose-1,6-bisphosphate and then it goes in reverse to glucose.

Same with the lipid stuff. They have basically over simplified it.
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Original post by nk96
My main Q was do they occur at the same time.


No I think either one or the other because if photolysis of water occurs then it's definitely non-cyclic and if it doesn't occur then cyclic will take place.
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Original post by ZQ110
No I think either one or the other because if photolysis of water occurs then it's definitely non-cyclic and if it doesn't occur then cyclic will take place.


Hmm yeah I thought so! Thanks :smile:
Original post by PropaneHorcrux
Can someone please explain all the G words for me please, getting a little confused :/ (like glycogenesis etc)


the -genesis suffix means create, the -lysis suffix means break apart/break down

glycogenesis therefore means the creation of glycogen (from glucose)

glycogenolysis is the breakdown of glycogen to form glucose
gluconeogenesis is the creation of glucose from amino acids and fats

The clues are in the name. If you're talking about glycogen as an end product, you have the prefix "glyco-" and the suffix "-genesis", because you're creating the glycogen.
With the formation of glucose, it's both a "-lysis" and a "-genesis" because you can get glucose both from breaking something down (glycogen) and using something to form it (amino acids/fats)
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Original post by domcandrews
Lol as if some guy on here was supposedly revising the f215 topics for the exam tomorrow!! thats jokes


lol imagine he gets higher than you :tongue:
Original post by hajs
After a prolonged period of fasting, glycogen levels in the liver are depleted. However the liver can still produce glucose by the process of gluconeogenesis. Describe one way in which this is done?

Anyone gonna try to answer that? I found it really difficult lol..


I would have said it was the conversion of lactate or pyruvate into glucose... not sure though!
[QUOTE=PropaneHorcrux;56715347]Can someone please explain all the G words for me please, getting a little confused :/ (like glycogenesis etc)
Think of lysis as breaking down and genesis as creating. Glycolysis not to be confused with glycogenolysis.
Original post by prof moriartress
Sodium/potassium ion pump actively removes Na+ from cells lining pct
Na enter back the cell in association with glucose through cotransporter proteins
Glucose diffuses back into the blood
Water potential in filtrate increases
H20 enters cells by osmosis


Thank you!
List of where all the stages of respiration and photosynthesis occur?
Original post by baymax96
List of where all the stages of respiration and photosynthesis occur?


Respiration:

Glycolysis - cytoplasm
Link/Krebs - Matrix of mitochondria
Oxidative Phosphorylation - Cristae in mitochondria

Photosynthesis:

Light dependent - Thylakoid membrane in chloroplasts
Light independent - Stroma of chloroplasts.
Can someone explain Apical Dominance and Sensecence
Original post by ZQ110
lol imagine he gets higher than you :tongue:


he probs will aswell!
Good luck everyone with the exam tomorrow! :smile: Just to check (I always worry I'm going to miss an exam and check multiple times haha), the exam is in the afternoon isn't it?
Glycolysis- cytoplasm
Link reaction- matrix
Krebs cycle- matrix
Oxidative phosphorylation- Christae/ inner mitochondrial membrane
Original post by baymax96
List of where all the stages of respiration and photosynthesis occur?

Respiration
Glycolysis - cytoplasm of cell (mitochondria don't have cytoplasms)
Link reaction and Krebs cycle - matrix
Oxidative phosphorylation - inner mitochondrial membrane/crista(e)

photosynthesis
Light dependent - thylakoid membrane
Calvin cycle -stroma
Original post by DaveUncle
it's not funny haha :frown: think i might be in trouble


ah dont worry, you'll be fine, still got time and the exam isn't till the afternoon
Original post by TotalerReinfall
What's F215? :/


Looooooooooool i'm done
Original post by alexthehuman
Im sorry if this has already been asked but im new to the thread. I can't find the 2014 f214 paper anywhere. Does anyone have it or know what the big questions were?


Biotutor has all the past papers


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