Why does DNA precipitate in NaCl and ethanol
NaCl neutralizes DNA reducing its reaction with water molecules.
Ethanol is less polar than water therefore DNA precipitates.
EDTA
Chelates metal ions which are cofactors for DNases. Also in anticoagulant for blood sample.
High 260/280 ratio
High pH of sample
High levels of RNA
Low 260/230 ratio
EDTA
Carbohydrates
Some proteins.
Sucrose
Increase solution osmolarity - cells burst
Triton X-100
Detergent that solubilises membrane proteins and lipids.
Destroys mitochondria and organelles.
What does SDS do?
A negatively charged detergent that binds proteins.
Dissociates multimeric proteins and causes polypeptide chains to denature .