Question

Suppose you had two solutions of DNA, one single stranded and the other double stranded, with equivalent absorbance of ultraviolet light. How would the concentrations of DNA compare in the two solutions. Explain your answer!

Answer 1

Single stranded DNA is denatured and it shows higher absorbance than the double stranded DNA.

For the equivalent absorbance of ultraviolet light double stranded DNA is more concentrated.

Denaturation of DNA causes double helix structure to unwind which leads to formation of single stranded DNA. When the DNA in solution is heated above 80 Degree celcius then double stranded DNA unwind to form single stranded DNA. Hence bases become installed and absorb more light. This is called hyperthermic effect.

Hypothermic effect stacked bases contains low absorbance in other words we can say hypochromicity is decrease of absorbance.

Hence double stranded DNA is more concentrated at equivalent absorbance of ultraviolet light.