Basic Nucleic Acid Extraction Methods

Question 1

Beer-Lambert’s Law

Answer 1

A = log¹⁰ (I⁰/I) = ecl

Question 2

Steps in DNA extraction

Answer 2

1. Pretreatment and washing
2. Cell lysis
3. Removal of contaminants
4. DNA precipitation
5. DNA suspension

Question 3

Physical methods on cell lysis:

Answer 3

Grinding
Shearing
Bead beating
Freeze-thaw

Question 4

Types of solution-based method on cell lysis

Answer 4

Chemical
Enzymatic

Question 5

What does SDS mean, and how does it remove contaminants in DNA extraction?

Answer 5

Sodium dodecyl sulfate

It makes the proteins anionic

Question 6

A broad-spectrum serine protease that can also degrade nucleases

Answer 6

Proteinase K

Question 7

What is used to remove RNA from a DNA extraction?

Answer 7

RNAse

Question 8

Extraction methods on DNA precipitation

Answer 8

Organic
Inorganic
Solid phase

Question 9

How does the organic method separate DNA from other components in a solution?

Answer 9

Uses high salt concentration in low pH with 1:1 phenol-chloroform

Solvation shell forms around the molecules

Question 10

Inorganic method is also called as ______

Answer 10

Salting out

Question 11

Optimal ratio of A260/A230 for DNA & RNA

Answer 11

2.0-2.2

Question 12

Optimal ratio of A260/A280 for DNA & RNA

Answer 12

1.8-2.0

Question 13

When dissociating a tissue, the sample must be _______ to inactivate intracellular RNAses

Answer 13

Frozen in liquid nitrogen or immeresed in a buffer solution