What is a proteome?

What is a proteome?

• A. The total number of genes in an organism
• B. The three-dimensional shape of a protein
• C. The proteins expressed across the entire organism under one set of conditions
• D. All the proteins expressed in a cell under one set of conditions

Answer: (D)

A proteome is the full set of proteins that a cell (or organism) expresses under a defined set of conditions. This reflects the active workhorses of the cell at a specific time and environment, and it can change depending on tissue type, development, and external factors. The key idea is that the proteome is a dynamic snapshot of which proteins are actually being produced and present, not just which genes exist or what proteins might look like structurally. This is why the best description is all the proteins expressed in a cell under one set of conditions. The total number of genes describes the genome, not the proteins being made. The three-dimensional shape refers to protein structure, not the collection of expressed proteins. And describing the proteome as spanning the entire organism under one condition is less precise, since different cells and tissues express different proteins under the same conditions.

A proteome is the full set of proteins that a cell (or organism) expresses under a defined set of conditions. This reflects the active workhorses of the cell at a specific time and environment, and it can change depending on tissue type, development, and external factors. The key idea is that the proteome is a dynamic snapshot of which proteins are actually being produced and present, not just which genes exist or what proteins might look like structurally.

This is why the best description is all the proteins expressed in a cell under one set of conditions. The total number of genes describes the genome, not the proteins being made. The three-dimensional shape refers to protein structure, not the collection of expressed proteins. And describing the proteome as spanning the entire organism under one condition is less precise, since different cells and tissues express different proteins under the same conditions.