Question

Explain DNA’s structure, specifically noting the role electric fields and forces play in it.

Answer 1

The structure of DNA as a double helix is stabilized by electrostatic forces, with a highly charged sugar-phosphate backbone. Hydrogen bonds between nitrogenous base pairs further reinforce the double helix structure. Electrostatic forces and hydrogen bonds are fundamental in maintaining a regular distance between the strands and within the base pairs.

Step-by-step explanation:

DNA’s structure is a double helix, with two strands winding around each other. Each strand is made up of a sugar-phosphate backbone and nitrogenous bases that protrude inward, where they pair with bases from the opposite strand. Electrostatic forces play a crucial role in maintaining the structure and stability of DNA. The DNA molecule is highly charged, with approximately 2qe of fundamental charge per 0.3 × 10−9 m. This charge contributes to the negative charge along the phosphate backbone, which is important as it helps to keep the two strands of DNA apart at a regular distance of about 1 nm, while the atoms within the base pairs are spaced at about 0.3 nm.

In addition, within the double helix, the hydrogen bonds between the nitrogenous base pairs (adenine-thymine and cytosine-guanine) help hold the two DNA strands together. These hydrogen bonds, while individually weak, collectively contribute to the overall stability of DNA's double helical structure because of the large number of base pairs in a DNA molecule.

Answer 2

DNA is made of a double helix strand each made of a glycophosphate backbone and nitrogenous bases as rungs to a ladder. They behave like bases because they are proton acceptors and hence have a net positive charge. Because they have charges they will have electric fields around them. Two pairs of bases on the opposite strands will, therefore, be bound by hydrogen bonds whose strength is governed by Coloumbs law – determined by the charges and the distance between them .