Question

Discuss with your teacher and find out how to distinguish between.
(a) Plasmid DNA and Chromosomal DNA
(b) RNA and DNA
(c) Exonuclease and Endonuclease

Answer 1

(a) Chromosomal DNA refers to the entire genome of an organism and depends on the genome for replication. It may be single stranded or double stranded and linear or circular. While plasmid DNA is extrachromosomal DNA that can replicate itself independently and always double-stranded circular DNA.

(b) DNA has deoxyribose pentose sugar and adenine and thymine as purines. It is found in the nucleus, mitochondria, and chloroplast only. While RNA has ribose pentose sugar and adenine and uracil as purines and found in nucleus and cytoplasm only. DNA replicates to form DNA and transfers genetic information from one generation to next whereas RNA is formed by DNA when required and directs the synthesis of protein in the body.

(c) Exonucleases are the enzymes that remove nucleotides from 5' or 3' end of DNA while endonucleases make cut within the DNA sequence by breaking the phosphodiester bond, not from its one of the end.