This unit 11d assignment achieved a distinction. This also comes in a package deal including all the unit 4 assignments which is cheaper than buying individual if you want all the assignments(a-d)
Stage 1- DNA extraction
This extraction can be extracted from the cheeks, saliva, semen etc. and is done mainly for
forensic testing or covid. Once the DNA is extracted, the cell membrane needs to break
down and this is done by adding a detergent. This leaves the DNA with its histone proteins.
To get the DNA on its own, we add protease to break down the histone proteins. Now we
have the DNA on its own; this needs to be placed into a centrifuge machine. This machine
spins around very fast and separates the DNA from the solution. The addition of ethanol is
taken place and the DNA now precipitates into a cloudy white solution.
DNA needs to be purified first, this is how you do it:
1. First you collect cells from inside of the cheek
You have to use a cotton swab to swab the inside of an individuals cheek to collect the DNA.
This swab will have to be placed inside a Eppendorf tube.
2. Then the burst cells open and release DNA
In order to close the tube, the end of the swab is cut off and a lysis solution is dropped inside
the tube via a micropippetor. This lysis solution's job is to separate the DNA; inside this
solution it contains proteinase K. This disrupts the nuclear envelope and cell membrane
which causes the cell to burst open and release DNA.Now the tube is placed in a warm
water bath. The DNA is wrapped extremely tight around histone proteins, the proteinase K
rip apart the histone which then frees the DNA.
3. Next the DNA needs to be separated from proteins and extra debris
The swab is removed from the water bath and the tube, and a concentrated salt solution is
added. The purpose of this salt solution is to clump the proteins and debris(this thing we do
not need) together. After this, the tube is now placed into a centrifuge and a tube filled with
water is placed opposite the original tube so that they balance each other in the centrifuge.
The centrifuge is now turned on, inside the centrifuge, it spins the tubes and very high
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller hhunss. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $11.05. You're not tied to anything after your purchase.
