Question

1. Why do polar molecules dissolve in water?
2. How do nucleotides come together to make a nucleic acid?

Answer 1

1. Polar molecules are defined as hydrophilic molecules which have an affinity towards dissolution in water. Water has a high dipole constant, it is not a linear structure, rather the negative charges on O- and positive charge on H- are arranges so that they donot coincide each other. This polar nature of water molecules attract charged and polar molecules. Polar molecules engage in Hydrogen binding with water..

The intermolecular forces between polar molecules and water is high, hence the bond between water-water molecule breaks and dissolves the polar substances.

2. Nucleotides are the building blocks of DNA and RNA. They consist of nucleoside base, phosphate group and sugar moeity. The nucleotides bind each other in a single strand by phosphodiester linkage. Between the bases in a double strand, hydrogen bond (base pairing) occurs between Adenine-thymine, and Guanine-cytosine.