Question

Nucleic acids exhibit secondary structure, justify with example.

Answer 1

Secondary structure of nucleic acids

When a long chain of polymers is arranged as a helix due to interactions between the constituents, this can be called a secondary structure.

• DNA forms a double helical structure. The secondary structure exhibited by DNA can be elucidated by the Watson-Crick model.
• RNA exists in a single stranded form, sometimes folded upon itself to form various structures, for example, a clover leaf model of tRNA.

So, secondary structure can be observed in both DNA and RNA.

Secondary structure of DNA - Justification

Secondary structure of DNA was proposed by Watson and Crick.

• This model says that DNA is a double helix that means it contains two polynucleotide strands.
• The polynucleotide strands are antiparallel, i.e., they run in opposite directions.
• The two polynucleotide strands are held together in their helical conformation by hydrogen bonding between bases present in the opposite strands.
• Sugar and phosphate group forms the backbone of the helix.

Since helix is an example of a secondary structure, hence, DNA exhibits secondary structure.