[tdx]

I'm currently doing the AQA Biology Unit 5 Specimen Paper: http://www.thomas-reddington.com/upl...p_specimen.pdf I'm stuck on question one, not a clue how to do it! any help will be appreciated

[VaVe]

ai, how is mRNA transcripted from DNA
aii, how do you get the tRNA sequence from mRNA
b, what does DNA have in the sequence that is removed from mRNA
c, look at the diagram and work out what would happen next without the antibiotic there.

[janet9]

For those having difficulty going from DNA to mRNA to tRNA and backwards, when I was doing this last year, I made a mini song a bit like the YMCA tune,

"GTCA, CAGU, GUCA"

GTCA is written in the first column, with CAGU following in the second columns, and so on so you have a 4x3 mini table. It helped me switch back and forth and really helped with deciphering sequences. It should look like so:

123
GCG
TAU
CGC
AUA

With 1 being DNA, 2 being mRNA, 3 being tRNA.
So UGC is mRNA, look to the left and you'll get ACG. Nice and easy. Remember the YMCA theme tune!

[tdx]

(Original post by VaVe)
ai, how is mRNA transcripted from DNA
aii, how do you get the tRNA sequence from mRNA
b, what does DNA have in the sequence that is removed from mRNA
c, look at the diagram and work out what would happen next without the antibiotic there.

aha, tis ok now, I forgot that thymine is replaced with uracil in RNA, thanks