Unit 6: Topic 8 - Biotechnology

Question 1

What is Gel Electrophoresis, and how does it work?

Answer 1

Gel electrophoresis separates DNA fragments based on size and charge. The process involves an electric current (positive electrodes) applied to DNA samples (which are negatively charged) in gell wells. This moves the smallest/least negatively charged samples the farthest from the wells, separating all the fragments based on their properties.

https://docs.google.com/document/d/12h2dYSvTD7fFZmVQ48juija7eakj1P9xsscoXMUEsYg/edit?usp=sharing

Question 2

What is PCR (polymerase chain reaction), and how does it work?

Answer 2

PCR (polymerase chain reaction) is a technique used to rapidly create many copies of a specific region of DNA from a sample. First, denaturation occurs by increasing the temperature to at least 94 degrees celsius to break the hydrogen bonds that form the double-stranded DNA. Next, the temperature is cooled to 50 to 60 degrees celsius to allow for annealing, which involves the primers binding to the single-stranded DNA. Finally, the temperature increases again to allow for extension using the Taq polymerase (DNA polymerase), which includes forming a complementary strand of DNA. These steps are repeated around 35-40 times to amplify the DNA sequence.

https://docs.google.com/document/d/12h2dYSvTD7fFZmVQ48juija7eakj1P9xsscoXMUEsYg/edit?usp=sharing

Question 3

What is Bacterial Transformation, and how does it work?

Answer 3

Bacterial transformation clones DNA. Bacteria are mixed with DNA, and some take up antibiotic-resistant plasmids when given a heat shock. Then, the bacteria are placed into an antibiotic plate, with the survivors being the ones that took up the plasmids. They then create colonies. The colony with the target plasmid (checked by other means, such as PCR) is then used for other purposes.

https://docs.google.com/document/d/12h2dYSvTD7fFZmVQ48juija7eakj1P9xsscoXMUEsYg/edit?usp=sharing

Question 4

What is DNA Sequencing (Sanger’s method), and how does it work?

Answer 4

DNA sequencing determines the sequence/order of nucleotides in DNA. The commonly accepted technique is the Sanger method which puts DNA through PCR but with the addition of modified nucleotides (also called ddNTP) which terminate the DNA polymerization prematurely. The ddNTPs have different fluorescent labels to distinguish them. After repeated multiple times, molecules with different lengths would be created, which can then be put through gel electrophoresis and a sequencing machine.

https://docs.google.com/document/d/12h2dYSvTD7fFZmVQ48juija7eakj1P9xsscoXMUEsYg/edit?usp=sharing