Question

Describe the structural, physical, and chemical characteristics of nucleic acids

Describe the emergent properties of polynucleotides and RNA (H-bonding, base-stacking, 3D folding)

Answer 1

Nucleic acids are of two types

1. Deoxyribonucleic acids (DNA)
2. Ribonucleic acids (RNA)

Nucleic acids are polymers and made up of monomer units called nucleotides which has the following components

1. Sugar (Deoxyribose sugar in case of DNA and ribose sugar in case of RNA)
2. Nitrogenase base
3. Phosphate group

Both DNA and RNA are made up of four nitrogenase bases namely

1. Adenine
2. Guanine
3. Cytosine
4. Thymine(only in DNA)
5. Uracil (only in RNA)

In RNA, uracil replaces the places of thymosine in the DNA. These four nitrogenase bases are classified as Purines (Adenosine and Guanosine) and Pyramidines (Thymosine and Cytosine) based on the ring structures.

Nitrogenase bases are linked to the sugar moiety by Glycosidic bonds and the adjacent nucleotides in the same strands were linked by Phosphodiester bonds.

DNA are double stranded in nature and mostly have right handed helix structure, while RNA is always single stranded and takes variety of structural forms depending upon its types. Some RNA also have catalytic roles in the cell other than playing its role as genetic material as like DNA.

In DNA, the two strands run in anti-parallel direction and the nitrogenase bases in the both strands are linked to each other via hydrogen bonds. There are two hydrogen bonds between Adenine and Thymine while 3 hydrogen bonds between Guanine and Cytosine.

Different forms of DNA are B-DNA (most common), A-DNA, Z-DNA, C- DNA, D-DNA and E-DNA. The most common B-DNA consists of 20 Angstrom in diameter and each nucleotides are stacked above each other with the gap length of 3.4 Angstrom having 10 nucleotides per turn with the length of 34 Angstrom.

Major types of RNA are transfer RNA, messenger RNA and ribosomal RNA all these have distinct roles in protein synthesis. transfer DNA simply called as tDNA have clover leaf like structure.While the other two forms doesn't have distinct structures and mostly remains associated with proteins.