Answer 1

DNA is a very large single molecule also called as macromolecule. It has a double helix structure, similar to a ladder, which is twisted at both ends. The DNA molecule is made up of basic materials called nucleotides and each nucleotide is made up of three components :

• Sugar
• Phosphate groups

Sugar and phosphate are arranged lengthwise.

• Nitrogen bases are attached sugar from inwards that extends to join hydrogen bond and the complimentary nitrogenous base from other strand.

The nitrogen bases are :

• Adenine(A)
• Guanine(G)
• Cytosine(C)
• Thymine(T)

Adinine pairs with Thymine with two hydrogen bonds. Guanine pairs with Cytosine with three hydrogen bonds.

During the interphase of cell cycle, DNA molecules duplicates for their equal distribution in the daughter cells during mitosis. The double helix opens at one end, makes the two strands free and from there new strands are formed.