We are about to investigate the secret to life.
Its called DNA.
And its in every cell of every living thing.
Whether your a bacteria or a human,
from fungus to the tallest tree.
Any living thing at all
and its very easy to get.
First, you need to choose your living thing. I've chosen strawberries, but you could choose anything.
You could choose wheat germ, you could choose chickpeas,
you could choose pesky brothers and sisters.
Although they don't like being chucked in blenders, so you might want to avoid them.
But, today we've got strawberries - its plants. Now, first thing thought, you need a little bit of warm
water.
You need to get some salt.
Salt is your buffer.
I've probably got about two-thirds of a teaspoon there. Dissolve that in your water.
Now,
for the strawberries.
Chuck them in.
Pips and leafy bits and all.
Keep enough strawberries in there so that you get about half the amount of water as you've got
strawberries.
Get your blender.
This just busts open the cell walls, assuming you've got a plant that is,
but it busts open the cell walls for a start.
That should do, get it nice and pulpy.
And you've just made a mess of your mum's kitchen, but that's OK.
Now, dishwashing detergent - straight from the kitchen cupboard.
This is very important stuff and again kitchen chemistry. The add the amount of liquid, about
15 - 20ml.
And then you've got to gently swirl it.
Now you should ask yourself, why are we adding dishwashing detergent? That's a very good question.
Think about why you use soap on your hands to remove grease.
Cell membranes, which contain all the DNA,
are made of fats or lipids, OK?
You add the dishwashing detergent
to break down those cell membranes which are made of fats, OK? Once those cell membranes have
broken down
all the DNA spills out and will then be swirling around in that liquid.
That means we can get it out.
Just gently
agitate it, we want to avoid froth. And then, we wait.
For about five minutes.
Gently swirling
every thirty seconds or so.
But did you know you share about 40% of your genes with the genes of a strawberry.
That means you're 40% related to a strawberry!
What you need to try and avoid
is this froth.
That's what you get if you swirly it too vigorously.
Its easy to get rid of though. All you need to do is get a bit of paper towel
and very carefully dab up that froth. The paper towel will soak it up.
And that removes it. Its just annoying a bit later on when you trying to actually extract your DNA.
Now we have to isolate the DNA. That's been sitting there and I've gently swirled it every now and then
for about five minutes.
So now we have to get
our DNA out and that requires
a funnel like this, a bit of filter paper, you can use coffee paper,
coffee filter if you've got one of those.
Hold it in there, and you just gently pour it in.
And that will slowly
filter out all the gunky bits and leaves and blobby bits
that are in there.
And what you should get through here
is a nice, basically strawberry juice. But with all the cell walls busted open, all the
cell membranes busted open
and the DNA just floating all freely around in the liquid.
And that means we can extract it. OK, the filter paper works very slowly so you might
have to give it a bit of a helping hand. Get your skewer, gentle swirl
and that will help it
move through the filter paper a bit quicker.
Now, that takes a long time.
If you're home in the kitchen and you don't have any of this sort of stuff, there's a very quick and simple way of
speeding this process up.
You need a bit of old open-weave kitchen cloth like this, a container of some sort,
stick that in there,
get your liquid again, strawberry juice,
pour a bit in there
and just strain it through the cloth.
Very carefully pick this up,
slowly,
you have to do it slowly, because otherwise it will squirt everywhere.
But gently
strain it through your cloth.
You don't get as pure a sample
but, it does the job.
Certainly if you're pushed for time, this way works equally as well.
And now, we have to add our enzyme.
Very simple - just meat tenderizer straight from the supermarket.
And all this does
is strip out a few of the proteins
that are clinging to the DNA.
Now I've only got
40-odd mil of strawberry juice here.
Get about a quarter of a teaspoon of meat tenderizer,
put it in there, get your skewer again, and
very, very gently stir in the meat tenderizer.
OK, the enzymes have done their job now. Hopefully, that's what you do.
Get yourself a couple of test tubes,
we'll use most of this, pour it into your test tube,
back in its rack.
Now, the next step is to add alcohol. You can use metholated spirits. OK, I've got 95%
ethyl alcohol here. Metho works just as well.
Or rubbing alcohol. You can get that from a chemist.
Little dropper. Now the trick is here
is to make sure the alcohol forms a layer on top
of the strawberry juice.
Its a bit like making a daiquiri really.
You add about
the same amount of alcohol as you've got strawberry juice in there.
So tilt your tube a little bit,
drizzle the alcohol down the side,
keep doing that.
Now, what will happen,
the DNA is insoluble in the alcohol.
It will move from the strawberry juice into the alcohol layer
and you'll see the DNA
in the alcohol layer. It the will be that
very snotty, cotton wool-looking stuff.
And the way you can get it out, because you can get it out,
get some skewers,
snap them in half.
Best end to use to get it out is the furry end that you just broke.
Because that catches the DNA much, much better.
And then, slowly.
Is a good sample, look at all that.
Now that is cool.
That is the secret to life.
All the instructions
on how to build a strawberry
are in that
cotton wool, snotty-looking stuff.
And the longer you leave it,
the more DNA will move
into your alcohol
layer.