Question

Hydrogen bonds vary in strength between 4-60 kJ/mol depending on environmental factors. In DNA they have a strength of approximately 6 kJ/mole.

a. For the following piece of dsDNA calculate the energy required to denature the two strands from one another. ATCGCGATCAGA (2 pt)

b. If a typical ATP→ADP = - 30 kJ/mole, how many ATP would DNA helicase require to separate these two strands. (2 pt)

Answer 1

Ans (a) The total number of hydrogen bond will be 6*2 (AT) + 6*3 (GC).

= 12 + 18 = 30 hydrogen bond.

Since, for breaking one hydrogen bond it requires 6 kj/ mole.

Thus, for breaking 30 hydrogen bond = 30* 6 kj/ mole.

Thus, 180 KJ/mole energy is required to denature the DNA shown in question.

Ans b. One ATP will produce - 30 KJ/ mole

So, for 180 KJ/ mole is equivalent to 6 ATP.

Thus, 6 ATP is required by helicase to separate the two strand.

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