Question

a)what is DNA ? how does it express itself?
b) what is the importance of DNA copying in reproduction ?

Answer 1

A) DNA is the genetic material which are made up of definite sequence of nucleotides.They are double stranded helix.The arrangement of nucleotides are specific in nature. DNA molecule is used in production of mRNA by a process called transcription.This mRNA codes for a particular protein by a process called translation.These proteins are expressive in nature.Thus DNA expresses itself by means of protein .

B)The fedility of replication or copying of DNA should be maintained.This ensures that same amount of genetic material is being transmitted to the next generation.Even a slightest change in nucleotide sequence may affect the species.

Answer 2

(a)  A gene is a segment of DNA that contains a set of instructions to make molecules that organisms need to survive. In a process called gene expression, these instructions are converted into some sort of product. And the product usually is either a protein or functional RNA.

(b) The replication  of DNA ensures that both the daughter cells get identical copies of the genetic material. HenceDNA copying  is important  in reproduction.