Understanding Protein Synthesis and the Proteome
The proteome represents the complete set of proteins expressed by an organism's genome. While the human genome contains approximately 20,000-25,000 genes, the proteome is vastly more complex, containing over 1 million different proteins. This remarkable expansion occurs through processes like alternative splicing, where a single gene can produce multiple protein variants.
Definition: The proteome is the entire collection of proteins that can be expressed by an organism's genetic material at any given time.
Cellular protein expression is highly dynamic and responds to various factors. These include metabolic demands, stress conditions, signaling molecules, and the cell's health status. Not all genes encode proteins - some produce non-coding RNAs like tRNA and rRNA that regulate gene expression.
The complexity of protein synthesis involves multiple cellular components working in concert. Intracellular membranes in protein synthesis play crucial roles in protein production, modification, and transport. These membrane systems include the rough endoplasmic reticulum (RER), which contains ribosomes for protein synthesis, and the smooth endoplasmic reticulum (SER) for lipid production.
Highlight: Alternative splicing allows cells to produce multiple protein variants from a single gene, greatly expanding the diversity of the proteome beyond what the genome alone would suggest.