Q.5 How does DNA of chromosome work?
Answer:
DNA
DNA is the genetic material. It performs its role by giving instructions for synthesis of specific proteins. Cell is actually controlled by its DNA. It is the DNA which makes characteristics or traits of cell or organism
Roles of proteins
Proteins may have different roles. Some perform structural roles e.g. Keratin while other acts as enzymes to control all bio-chemical reactions of cells.

Traits
Traits are made by specific proteins. Sequence of Amino acids
Sequence of amino acids is controlled by specific sequence of nucleotides in DNA.
Protein Synthesis
Protein synthesis takes place in two steps.
(i) Transcription         (ii) Translation
Transcription
It is a process in which specific sequence of DNA nucleotides is copied in the form of messenger RNA (mRNA) nucleotides.
Translation 
The mRNA carries sequence of its nucleotides to ribosomes. The ribosome reads this sequence and joins specific amino acids, accordingly to it, to form protein. This is called as translation.