All pre- and post-lab questions. Micropipette challenge: color spectrum. DNA iso
ID: 94782 • Letter: A
Question
Explanation / Answer
Answer=
DNA isolation function of reagents
1] extraction buffer- components of extraction buffer causes cell lysis
Tris in buffer-buffersthe pH of cells
EDTA - deters the DNase activity ,weakens the cell membrane stability
chloride - enter into the cells by ionic transport along with water by diffusion
it neutralizes charges on DNA
2] Mercaptoethanol- cleaves the disulphide bridges of proteins & helps in denaturation of membrane proteins & cytosolic proteins
3] SDS -lyses cell
4] pottasium acetate- DNA in nucleoplasm is neutralized by pottasium acetate .K+ions binds with negative phosphate backbone of DNA & shield them .this favors the DNA precipitation from ethanol in cold condition
5] phenol/choloform /isoamyl =separates into phases & removes gunk
6] Isopropanol - precipitates DNA
7] Ethanol - when added in cold condition DNA strands come close together & coalesce
it removes salt
Answer= 2]
Agarose gel electrophoresis
principle= is a method used for the separation of nucleic acids on the basis of their size by the aid of electric field where negatively charged molecules migrate towards anode i.e.positive pole .The migration flow is determined solely by the molecular weight where small weight molecules migrate faster than large weight molecules
function of reagents =
1] Ethidium bromide - is a molecule commonly used to visualize DNA in agarose gel electrophoresis
it binds to DNA & fluoresces under proper conditions it is interchelating agent
2] Loading buffer- For completion of electric current ,the gel must be bathed in a salt solution called as electrophoresis buffer