Year 10 DNA Pracs.

[Marama T]

I wash and reuse zip lock bags all the time. Eventually they do have to go in the bin, sadly. Fortunately there are now some excellent compostable bags available. (Thankfully, my head teacher would never instruct me to not reuse something.)

[RosalieL]

I wash and reuse zip lock bags all the time. Eventually they do have to go in the bin, sadly. Fortunately there are now some excellent compostable bags available. (Thankfully, my head teacher would never instruct me to not reuse something.)

I find the regular ones don't even last the prac. Maybe our kids are a bit too rough with their smooshing of the fruit? They usually have to double bag them to avoid too many leaks.

[Marama T]

Surely there's a way to "smoosh" fruit without a bag - mortar and pestle? Sounds like the bags do a pretty ordinary job.

[Wayne]

I've attached what we do. It is a bit more intensive than the zip lock bag method, but it eliminates the use of bags which is good for the environment.

[Prima]

I've attached what we do. It is a bit more intensive than the zip lock bag method, but it eliminates the use of bags which is good for the environment.

Wayne thanks for sharing, that method looks great! So much background detail as well

[bigmack]

Had teacher ask for this prac but was nervous because she had never had much success.

When queried , she mentioned fresh strawberries coffee filter papers and refrigerated Isopropyl alcohol .

I told her we never had problems with Frozen strawberries , Tulle or other coarse weave netting and metho .

She was sure the chilled Rubbing alcohol was best because all the recipes used it .

So I went to Spotlight and spent about $3 on some polyester Tulle , bought some frozen strawberries and smooshed ( with added extraction juice ) , split the filtrate into two test tubes .

On the left , chilled Rubbing alcohol . On the right , good O’l Diggers metho straight from the Flam cabinet.

IMG_0710.jpeg

Almost instantly the Metho one started to coagulate the DNA . It took almost 10min before there was a noticeable delineation in the Chilled Rubbing Alc test tube .

Teacher is sold .Room temp metho is the winner .

Oh and the other thing was she had always used a beaker nit a test tube so it was soooo much harder to see the delineation.

[RosalieL]

Well that is interesting! We use metho but I have a bottle stored in the freezer for this purpose!