Going under the Ensembl one can look up particular genes as well as particular transcripts. In the process of doing so you can view the sequence, such as the sequence here. Now I understand that a particular gene can have many different transcripts (the gene I link in this instance has 8 different transcripts). So what is Ensembl showing when it displays the sequence? The longest transcript? Thank you for any clarification.
From Ensembl glossary:
For ensembl genes:
For transcript:
and the building of a coding gene is explained here: http://asia.ensembl.org/info/genome/genebuild/automatic_coding.html