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[andrewloppol]

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[qshyrn]

Just doing Insight 08... had no idea what RNA interference was.

Don't think it'll be on exam either, but does anyone know about it?

yeah, dont think its on the exam  buts its not that hard to learn:
so basically what happens is you insert a Double stranded RNA into a cell (dsRNA).  An enzyme called DICER then cuts this RNA into small pieces known as Small-interfering RNA (siRNA). These siRNA associate with intracellular proteins to form a complex known as RISC (Rna-induced silencing complex i think). What this RISC does is that it targets the mRNA (its lead by the siRNA apparently) -the mrna thats complementary to one of the strands of the dsRNA originally inserted.
This way, silencing alleles of genes which cause disorders like Huntington's is possible

[minilunchbox]

It's mentioned on the VCAA so no guarantees on it not being on the exam. But I think the main thing you would need to know is that siRNA destroys complementary mRNA by binding on to them and thus 'targeting' them for other enzymes to splice. This would cause protein synthesis to be impaired therefore altering gene expression without changing the base sequence of DNA.

It's also able to target particular genes/proteins because it's more precise.

[minilunchbox]

It's in "Recent developments and advances in evolutionary theory" under Support Material on the Biology page. Not sure about the study design.

[mmmmm]

i think lac operon was on there too. I'm pretty sure we don't need to know about that right? Is it just me, i got pretty bad on that exam

[hyperblade01]

You might wanna learn about operons as I've seen it on a few papers i've done... it reminds me of Unit 3 with biochemical pathways, enzyme active sites etc..

EDIT: Or was biochemical pathways from chemistry Unit 3 ?

[claire.anglim]

Sorry this is the only bit I could find about Operons in my notes, does anyone have a summarised form that would be suitable for deffinitions in the exam?


An operon is a functioning unit of key nucleotide sequences of DNA including an operator, a common promoter, and one or more structural genes, which is controlled as a unit to produce messenger RNA (mRNA), in the process of transcription by an RNA polymerase.

Bacterial genes are organized into operons, or clusters of coregulated genes. In addition to being physically close in the genome, these genes are regulated such that they are all turned on or off together. Grouping related genes under a common control mechanism allows bacteria to rapidly adapt to changes in the environment.

The best-studied examples of operons are from the bacterium Escherichia coli (E. coli), and they involve the enzymes of lactose metabolism and tryptophan biosynthesis. Because the lactose (lac) operon shares many features with other operons, its organization and regulation are described in detail below.