What are exons and introns? What is the difference between them?

Introns and exons are parts of genes.
Exons code for , whereas introns do not. A great way to remember this is by considering introns as intervening sequences and exons as expressed sequences.
Exons are parts of DNA that are converted into mature messenger RNA (mRNA). The process by which DNA is used as a template to create mRNA is called transcription.
This mRNA then undergoes a further process called translation where the mRNA is used to synthesize proteins, via another type of molecule called transfer RNA (tRNA).
Introns are parts of genes that do not directly code for proteins.
Introns can range in size from 10’s of base pairs to 1000’s of base pairs.
source: http://www.news-medical.net/health/What-are-introns-and-exons.aspx
Exons are coding areas whereas introns are non-coding areas.
An exon is termed as a nucleic acid sequence which is represented in the RNA molecule. Introns, on the other hand, are termed as nucleotide sequences seen within the genes which are removed through RNA splicing for generating a mature RNA molecule.
It can also be seen that introns are less conserved which means that their sequence changes very frequently over time. On the contrary, exons are very much conserved.
Exons are codes of proteins; introns are not at all implicated with the protein coding.
Exons can be termed as DNA bases which are translated into mRNA. Introns are also DNA bases that are found in between exons.
Introns are very much common in the genome of higher vertebrates such as human beings and mice but unlikely to be seen in the genome of certain varieties of eukaryotic micro-organisms.
Read more: Difference Between Exons and Introns | Difference Between | Exons vs Introns http://www.differencebetween.net/science/difference-between-exons-and-introns/ixzz3fvpqGKlG