F215 - Revision thread 13th June 2011

Scroll to see replies

Reply 2380

atman7

Could anyone just tell me what DNA polymerase and the DNA primers roles are in PCR

Reply 2381

Wailinza

Original post by CoventryCity

Ahh I am OCR for Chemistry.
Got an A in my January exam, find it way easier than Biology

I've got OCR F325 Chem on Wed . . . . but have my Maths C3 first thing tomorrow morning and I've just about spent the whole day doing biology - there is just so much to cover.

Reply 2382

mazam

Original post by atman7

Could anyone just tell me what DNA polymerase and the DNA primers roles are in PCR

Primers they bind to the single stranded dna with complementory base pairing , A with T c with G ... The temperatures at 55 to allow hydrogen bonds to form.

Dna polymerase is thermophillic it seals the nucleotides and primers at 72 degrees .

Reply 2383

litsamc

Original post by Signed Solution

What is in vitro cloning? I think I've confused myself after looking through the internet.

In vitro is artificially i.e. fertilising egg + sperm in a lab
In vivo is in a live cell eg a yeast cell/bacteria

Reply 2384

thecookiem0nster

Original post by thepwince

Just type in hardy weinberg problems into google, there's plenty of examples... and they're all the same format really.

Why didnt I think of that :/ Thanks

Reply 2385

gradu

Going through revision guides like a boss!!

Gonna be a late night, but exam ain't till 13.00 :smile:

I'll get up at 8am, and read though again on the big essay - esque questions

Reply 2386

bambinooo

Original post by atman7

Could anyone just tell me what DNA polymerase and the DNA primers roles are in PCR

At stage 1 of pcr: DNA polymerase, primers and free nucleotides added to reaction mixture and the mixture is heated at a temp of 95 degrees to break hydrogen bonds (DNA HELICASE IN NATURAL DNA REPLICATION)
- stage 2 involves primers (short single stranded sequences of DNA)annealing to the 3' ends of the seperated DNA strands. DNA polymerase enzyme cannot bind directly to DNA strand, so primers required to DNA polymerase to bind to.
-Stage 3, mixture heated to 72 degrees (optimum temp for DNA polymerase) and the enzyme extends the primers by adding free nucleotides (like in natural dna rep).

Once the enzyme reaches the end of the of the dna strand, a new double strand is created.

-can be repeated many times....exponential growth i.e. amount of dna strands : x2, x4, x8 ect!

Reply 2387

*Funky-buddha*

Sorry if it's been asked before but does anyone have the mark scheme for the Jan 2011 paper it'd be a massive help!

Reply 2388

kabolin

how much did you guys revise today for this exam?

Reply 2389

heartskippedabeat

Original post by *Funky-buddha*

Sorry if it's been asked before but does anyone have the mark scheme for the Jan 2011 paper it'd be a massive help!

it's on page 12 :smile:

Reply 2390

heartskippedabeat

Original post by kabolin

how much did you guys revise today for this exam?

pretty much all day... i've been revising this for about 10 hours a day for the last week and i still feel like i dont know anything :tongue:

Reply 2391

airdoc

Original post by kabolin

how much did you guys revise today for this exam?

How many hours have there been since midnight :cool:

Reply 2392

gradu

Original post by airdoc

How many hours have there been since midnight :cool:

I've done the same as you!

Doesn't seem "too" bad in fairness. I have a solid idea of what will come up :-)

I predict these essay questions:

- How is Insulin produced..( refering to recombinant DNA etcetc )
- PCR
- MUSCLES
- Brain

I'll get a chinese before my exam :biggrin:

Reply 2393

susan23

I thinnk most people have gone to bed now.

Reply 2394

Bullit

Original post by 786girl

what does it mean when it says about apoptosis

nitric oxide can make inner mitochondrial membrane more permeable to hydrogen ions and dissipating the proton gradient? :sssss
something to do with more atp perhaps?

My guess would be something to do with the resulting lower pH being optimal for the enzymes that break down the cell cytoskeleton. Also the protons interfering with hydrogen bonds in the cell.

Reply 2395

TobeTheHero

What exactly might come up? can anyone give me a list of what might come up so I could concentrate on that and not waste any valuable time. Thanks

(edited 12 years ago)

Reply 2396

susan23

Original post by TobeTheHero

What exactly might come up? can anyone give me a list of what might come up so I could concentrate on that and not waste any valuable time. Thanks

Here don't tell anyone ok...open your textbook and open pages:

Spoiler

Reply 2397

Luke0011

Original post by TobeTheHero

What exactly might come up? can anyone give me a list of what might come up so I could concentrate on that and not waste any valuable time. Thanks

Look at the specification.

Knowing OCR, anything there could come up.

Reply 2398

yesioo

31 pages of size 11 font later, I've covered every single point on the spec and i'm still not ready for this exam -.-

send it to me? :colone:

Reply 2399

Twinkles

Original post by Wailinza

I've got OCR F325 Chem on Wed . . . . but have my Maths C3 first thing tomorrow morning and I've just about spent the whole day doing biology - there is just so much to cover.