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AQA BIOL5 ~ 17th June 2013 ~ A2 Biology

Original post by KaranbirBandesha

How do you know how the restriction endonuclease cuts the dna double strand, like sometimes it leaves blunt ends and sometimes sticky ends how do you know how it might cut it, if anyone wants to answer my question

Not really sure what your asking, but restriction enzymes will cut a specific section of DNA if it has a complimentary base sequence to it so it can attach aka a restriction site. It attaches and then cuts the DNA at this point. You can't tell if a sticky end or blunt end is produced just from knowing a restriction endonuclease is used but most times the examiner wants you to assume sticky ends are produced. Like when talking about making recombinant DNA you cut the plasmid and donor DNA with the same restriction enzyme so that they will have complimentary sticky ends and so they can join together. I've never seen a question that talks about blunt ends being produced from restriction enzymes.

Hope this helps.

Reply 4381

jonnyb123

9

Original post by Jake1313

2 is correct.

Thanks for clearing that up!

Reply 4382

wrnicholls

2

What are the chances of gene technology coming up?
And the questions that might... how much do you think doesn't require knowing the topic.

I've revised all but gene technology so far, and that's a biiiig topic.

Reply 4383

EmilyBoorman

Can somebody please explain to me what a DNA primer is and why it is needed? :smile:

Reply 4384

jonnyb123

9

Original post by wrnicholls

What are the chances of gene technology coming up?
And the questions that might... how much do you think doesn't require knowing the topic.

I've revised all but gene technology so far, and that's a biiiig topic.

After tomorrow I'll never have to look at that stupid bloody section again.

Original post by EmilyBoorman

Can somebody please explain to me what a DNA primer is and why it is needed? :smile:

Enables DNA replication to start as it binds to the start of the DNA fragment you want to reproduce (because it has bases complementary to this section of the fragment), and DNA polymerase can only add complementary nucleotides to the end of already existing chains. Make sense?

edit: oh they also stop the two separate DNA strands from simply rejoining.

(edited 10 years ago)

Reply 4385

EmilyBoorman

Original post by jonnyb123

After tomorrow I'll never have to look at that stupid bloody section again.

Enables DNA replication to start as it binds to the start of the DNA fragment you want to reproduce (because it has bases complementary to this section of the fragment), and DNA polymerase can only add complementary nucleotides to the end of already existing chains. Make sense?

edit: oh they also stop the two separate DNA strands from simply rejoining.

Yes, thank you very much! :smile:

Am ****ting myself

Original post by Anjna

Condensation and hydrolysis and their importance in biology. ideas anyone?

Off the top of my head I would talk about how proteins are made via condensation reactions between amino acid monomers to form peptide bonds (translation). (e.g glucose + glucose = maltose)

Talk about how enzymes hydrolyse large insoluble molecules into small soluble ones for digestion and absorption (e.g starch digestion)

Talk about siRNA and how it binds to an enzyme to hydrolyse mRNA into smaller pieces to prevent translation.

Use of restriction endonucleases in making recombinant DNA were they hydrolyse the plasmid to make it form sticky ends complimentary to donor DNA so they can be joined together via DNA ligase.

I cant think of that many for this one sorry.

Reply 4388

wrnicholls

2

Anyone got any notes on DNA Technology I could have please?
Like the only module standing in my way. :frown:

Text me a photo or something.

Reply 4389

Neenee1

Please can someone explain core sequences?

Reply 4390

MLogan

Original post by James A

Got the same as you for C4! :colone:

I did mine in June 12 though!

I guess a HI5 is in order :P Good Luck for tomorrow :smile:

Reply 4391

REGA91

Does anyone have any ideas for an essay on hydrogen bonding? I can only think of transpiration of water/transport through plant, protein structure and DNA and RNA base pairing. Does anyone have any other ideas? Thank you! :smile:

Reply 4392

KaranbirBandesha

Original post by Ravz94

Not really sure what your asking, but restriction enzymes will cut a specific section of DNA if it has a complimentary base sequence to it so it can attach aka a restriction site. It attaches and then cuts the DNA at this point. You can't tell if a sticky end or blunt end is produced just from knowing a restriction endonuclease is used but most times the examiner wants you to assume sticky ends are produced. Like when talking about making recombinant DNA you cut the plasmid and donor DNA with the same restriction enzyme so that they will have complimentary sticky ends and so they can join together. I've never seen a question that talks about blunt ends being produced from restriction enzymes.

Hope this helps.

Thanks for that! and yeah the questions are mostly bout sticky ends but was just wondering cause in the text book it says that restriction endonucleases can cut DNA in two ways and one was where blunt ends are shown rather than sticky, but thanks anyways!

Reply 4393

MLogan

Original post by REGA91

Does anyone have any ideas for an essay on hydrogen bonding? I can only think of transpiration of water/transport through plant, protein structure and DNA and RNA base pairing. Does anyone have any other ideas? Thank you! :smile:

Essay A Hydrogen bonds and their importance in living organisms.
Section of specification
Hydrogen bonds associated with the properties of water 15.1 The passage of water through a plant and cohesion tension
Hydrogen bonds associated with secondary and tertiary structure 10.4 The structure of proteins, starch and cellulose 10.5 Enzymes
Hydrogen bonds associated with nucleic acids 11.3 DNA as genetic material, structure of nucleic acids 11.4 Gene technology

This came up in a really old paper :smile:

Reply 4394

F1's Finest

21

Original post by MLogan

I guess a HI5 is in order :P Good Luck for tomorrow :smile:

Best of luck to you as well!

Reply 4395

AspiringGenius

15

Original post by Anjna

Condensation and hydrolysis and their importance in biology. ideas anyone?

-relationship with ATP- creating and releasing energy
-relationship with forming and breaking down polymers (carbs, proteins etc).

not realyl a huge amunt else. not my kind of essay tbh.

Reply 4396

Roder09

What is the point of the sanger method/terminator nucleotides? What is achieved (after all its a random process when the terminator joins on)

Reply 4397

_jamie

4

Original post by Roder09

What is the point of the sanger method/terminator nucleotides? What is achieved (after all its a random process when the terminator joins on)

You can work out the sequence of the DNA

Reply 4398

AlisonNaomi

I have had to sit units 1, 2, 4, (in the last few weeks) because of various reasons. My brain has been doused with biology revision, but now my brain is blank and I feel as if I won't remember a thing for the essay. Currently attempting plans but I can't think of anything!

Reply 4399

Ravz94

Could anyone please tell me the difference between a marker gene and a gene/DNA probe? I've been confused about this for a while now :s-smilie:

AQA BIOL5 ~ 17th June 2013 ~ A2 Biology

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