18 Questions
What is the primary role of NaCl in DNA extraction?
To chelate magnesium ions and inactivate DNAse
What is the purpose of proteinase K digestion at high temperatures?
To unfold and degrade proteins at high temperatures
Why is SDS used in DNA extraction buffer composition?
To disrupt membranes due to its amphipathic nature
What is the role of phenol in DNA extraction?
To denature proteins and dissolve denatured proteins
Why is EDTA used in DNA extraction buffer composition?
To chelate magnesium ions and inactivate DNAse
What is the purpose of adding 100% ethanol or isopropanol in DNA extraction?
To precipitate DNA and remove impurities
What is the primary purpose of grinding the sample with liquid nitrogen in DNA extraction from plant cells?
To break down cell wall material and inactivate harmful cellular enzymes and chemicals
What is the role of EDTA in the CTAB extraction buffer?
To chelate magnesium ions and inactivate DNAse
What is the effect of high ionic strength solutions on CTAB?
CTAB forms complexes with proteins
Why is NaCl added to the CTAB extraction buffer at concentrations of more than 0.5 M?
To remove polysaccharides from the DNA extract
What is the purpose of using CTAB in DNA extraction from plant cells?
To precipitate nucleic acids and acidic polysaccharides
What is the advantage of using CTAB in DNA extraction from organisms that produce large quantities of polysaccharides?
It is useful for purification of nucleic acid
What is the purpose of adding 0.54 volume of ice-cold isopropanol to the sample?
To precipitate the DNA and remove salt
What is the primary function of the 70% ethanol wash step in DNA extraction?
To remove salts and other contaminants from the DNA sample
What is the purpose of adding RNase to the sample during DNA extraction?
To degrade any RNA present in the sample
What is the primary function of the centrifugation step at 10,000 rpm for 10 minutes?
To separate the aqueous and chloroform phases
What is the composition of the buffer used to resuspend the DNA pellet?
1X TE buffer or RNase-free H2O
Why is it important to leave some of the upper phase behind when transferring the aqueous layer to another tube?
To prevent the pickup of any interphase or lower phase
This quiz covers the role of various chemicals and steps involved in the DNA extraction process. Learn about the functions of NaCl, EDTA, and SDS in DNA extraction. Understand how these substances contribute to the process of DNA isolation.
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