Chemistry of Life

Molecular genetics, biochemistry


The term genome refers to the complete hereditary information of an organism (archival DNA or RNA for some viruses). The genome includes both the genes (coding-sequences, domains) and the non-coding sequences – both exons, which include open reading frames, and introns. Similarly, the term proteome refers to an organism’s collection of proteins.

The genome possesses:
1. Exonal segments of DNA whose sequences encode the pre-mRNA, and ultimately polypeptide and protein sequences.
2. Intronal segments that are excised by pre-mRNA splicing before transport of mature mRNA through nuclear pores to the cytoplasm where ribosomal translation into ribosomal polypeptides and proteins occurs.
3. A start site for transcription, called the initiator gene.
4. Promoters, both a basal or a core promoter located within about 40 bp of the start site, and an upstream promoter, which may extend over as many as 200 bp farther upstream.
5. Enhancers.
6. Insulators.
7. Silencers.

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Blogger qtr said...

In general, a consensus sequence is that idealized sequence in which each position represents the base/amino acid most often found when many sequences are compared. A genetic consensus sequence is a sequence of nucleotides that is common to different genes or genomes. There may be some variations but such sequences show considerable similarity. So, a consensus sequence is the prototype sequence that most others approach.

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. . . transcription begun 10/06/06