(a) Differentiate between exons and introns.
(b) What is a plasmid? Why is it selected as a vector?
(a) Exons Introns
(i) The coding sequences or expressed (i) Non-coding sequences which do
sequences that appear in mature or not appear in mature or processed
processed RNA are called exons. RNA are called introns.
(ii) Exons are codons that code for ami (ii) Introns do not code for amino
no acid sequences. acids.
(b) 1. Plasmid is a circular extra chromosonal DNA in bacteria.
2. It has the ability to replicate within bacterial cells independent of the control of
3. Plasmids are high in number per bacteria, if we link an alien piece of DNA with
plasmid DNA, we can multiply its number equal to the copy number of the plasmid.