DNA estimation can be done by:
Ans. b. Spectrophotometer (Ref: Laboratory Protocols. ClMMYT Applied Biotechnology Center, 2nd Edition; http: //en. wikipedia. org/wiki/ Spectrophotometer_ for_Nucleic_ Acid_ Measurements)DNA estimation can be done by spectrophotometer.DNA Quantification and Quality AnalysisAfter isolation of DNA. quantification and analysis of quality are necessary to ascertain the approximate quantity of DNA obtained and the suitability of DNA sample for further analysis.This is important for many applications including digestion of DNA by restriction enzymes or PCR amplification of target DNA.The most commonly used methodologies for quantifying the amount of nucleic acid in a preparation are:Gel electrophoresisSpectrophotometric analysisSpectrophotometric DeterminationAnalysis of UV absorption by the nucleotides provides a simple and accurate estimation of the concentration of nucleic acids in a sampleQ.Components of SpectrophotometerSpectrophotometerBiomolecules absorb light at characteristic wavelengths, just as tryptophan, tyrosine and to a much lesser extent phenylalanine absorb ultraviolet light near a wavelength of 280 nmQ.The fraction of incident light absorbed by solution at given wavelength depends on thickness of absorbing layer (path length ) and concentration of the absorbing species.Lambart Beer LawAbsorbance = log Ideg/I = eClWhere e is molar extinction coefficient and it has been assumed that incident light is parallel, mono chromatic (of single wave length) and solvent and solute are randomly oriented.So each successive millimeter path of absorbing solution absorbs not a constant amount but a constant fraction of light.However, with fixed path length absorbing layer, absorbance is directly proportional to the concentration of absorbing soluteQ.So it can be used in quantitative estimation of DNA, RNA or aminoacidsQ.
Spirometer
Spectrophotometer
pH meter
Sphygmomanometer
Molecular Biology Techniques