F215 - Revision thread 13th June 2011

i guess, yeah. I'm hoping for the whole "how does meiosis lead to variation within a population" kind of question.

basically you just need to know how its done
first you get the source of the genetic information so mRNA which codes for the insulin protein, you then use reverse transciptase to convert this into cdna, primers can then be added to the cdna which are complementary to the sticky ends of the plasmid
plasmids are useful as bacteria actively take these up.
you cut the plasmid open using restriction enzymes , these cut the plasmid at a specific site, this is why you know which primers to add, the cdna can then bind to the plasmid, the plasmid is sealed using DNA ligase, this is your recombinant dna.
however we aren't quite done yet
you need to know which cells have taken up plasmids and which of those have a recombinant plasmid with the gene we want
so you use replica plating, basically you know the plamid i was talking about earlier you choose this carefully so it has genes for antibiotic resitance in it , which original bacteria do not, usually ampicillin and tetracycline, you then use a restriction enzyme which cuts through one of these antibiotic resistance genes, usually tetracyline, therefore if you grow colonies of the bacteria on agar, those that have taken up the plasmid will grow on ampicillin those that haven't are killed, so basically you then see which grow on tetracycline , those that grow on ampicillin but not on tetracycline are the ones you want so you takes these bacteria and let them reproduce to levels significant enough to produce industrial amounts of insulin and that's about it
think the book probably explains it clearer than me though so have a look in the cgp revision guide

I thought the definitions of the biological species concept and the phylogenetic species concept were the other way around?

Biological species concept - organisms who are similiar in appearance, physiology, anatomy, biochemistry and genetics, and who are able to interbreed to produce fertile offspring. They also remain reproductively isolated from other species.
Phylogenetic species concept - organisms who are geopraphically separated and morphologically and behaviourally distinct from other species, even if their breeding capabilities are unknown.

How would you go about answering that? Sorry, are you able to give like a rough plan or something, I havent got a clue! (: Thanks (:

Yepp

The ocr book says the other way around

ahhh thankyou soo much
you know the ampicillin and tetracycline bit.. do we really need to know all that detail? coz in the exam wouldnt they ask about another type of thing?
oh and btw, you know you said the ones you want are those that grow on ampicillin but not on tetracycline.. why is that?

ahhh thankyou soo much
you know the ampicillin and tetracycline bit.. do we really need to know all that detail? coz in the exam wouldnt they ask about another type of thing?
oh and btw, you know you said the ones you want are those that grow on ampicillin but not on tetracycline.. why is that?

Could I have some sympatric speciation examples and biotic and abiotic environmental pressures please?

Thanks in advance

give me the list pleaseee!!

What's bacterial conjugation?

Also does anyone know what reverse transcriptase is used for?

is this correct?
hydrolysis of ATP = breaks crossbridge?

is this correct?
hydrolysis of ATP = breaks crossbridge?

is this correct?
hydrolysis of ATP = breaks crossbridge?

Crossing over in prophase 1 would give different allele combinations e.g could have a bit of chrosome 2 swapped with another bit of chromosome 2.

Random assortment of bivalents/chrosomosomes during metaphase 1

Random assortment of chromatids during metaphase 2

Fertilization is random too.

Even interphase, DNA replication - can go wrong and produce variation > but it's a bit too much i think

What's bacterial conjugation?

Also does anyone know what reverse transcriptase is used for?

Just encase anyone is revising from this see the corrected bold bit!

For other questions...I'm probably in bed by 10pm today, Mechanics 2 maths and biology tomorrow, then geography the next day! Ah well, after C4 I'm on holiday the day after so I'll just look forward to that.