Question

2- Which of the two DNAs A and B are pure. Explain your choice. 17.90 16.00 9.00 ON Phenol 14.00 DNA 12.00 10.00 10 mm Absorbance 10 mm Absorbance 0.00 220 230 240 250 260 270 280 290 300 310 320 330 340 350 Wavelength im! 220 230 240 250 260 270 280 280 560 510 320 330 340 360 Wavelength ihm)

Answer 1

o The graph B shows pure DNA sample. DNA absorbs at 260 nm and graph B Shows a clear peak at 260 nm while graph A shows phenol and other contami - nants along with DNA. So the graph A. belongs to an impure DNA sample as the peak of DNA is shifted from the normal 260 mm wavelength indicating contamination. o Pipette A is set at 32.7 ul. | This is the way you adjust pilette volume . This can be explained practically. | You rotate the digito until you get your desired valume. It can be best explained practically. Answer is .. Option ③ Lysis of cells will be the first step irrespective of the sample first of all you need a well homogenized cell desate so that you can froceed further. ① DNA is found in (a) Upper aqueous phase. If you berform phenol chloroform based isolation. Phenol es denser than water so et moxes with chloroform and forms a mixture. water is less dense than tanwater so it remains above organic phase fos ancare

(bhenol chloroform). Nucleic acids are bolar so they remain in upper aqueous bhase DNA): Protuns stay at the interphase and lipids stay in the organic phase. a DNA is precipitated using is opropanol obtion (b)! Nucleic acids are holar and water soluble. Alohal in this case, isolpropanol is less bolar than water , so alcohol when added to solution containing DNA solubilises ions and DNA. al Poly T oligomers bound to matrix resin calumn can be instatod a selectively lesolate messanger RNA. This is a I due to the fact that mersanger RNA has a poly A tail. Sop I oligomen's will wind to paly a tail on messanger RNA. C A and T for bond in nucleic acids) CA=T) O option ② is correct. Nuclele acid ean quantified very quickly and simply I by spectrophotometry at 260 nm. a Electrophoresis is to visualize DNA Leped_ab OmScanner

Sequencing will elucidate sequence of nuckotided in DNA : Enzyme immunoasson will not help in this case. DNA absorbo at 260 nm because of the nucleotides present in them I c the heterocyclic rings specificall et al. RNA also aboobs at I 260 nm e l ca mase) Proteins absorb at 280 mm I because of aromatic amino acids. So correct answer is d an fessdanned with CimScanner grovt ut i