Question

Why is the proteome larger than the genome?

a) Proteins may be modified by covalent addition of a variety of molecules
b) Not all genes are expressed in all cells at the same time
c) Many coding genes are transcribed into mRNA which can be alternatively spliced, and those transcripts produce different proteins so the ratio of the number of protein molecules to the number of genes is greater than 1
d) The total amount of protein in a cell as measured by mass is always greater than the total amount of DNA

Answer 1

The proteome is larger than the genome due to various factors including protein modifications, gene expression patterns, alternative splicing, and the greater mass of proteins compared to DNA.

Step-by-step explanation:

The proteome is larger than the genome due to several factors. First, proteins may be modified by covalent addition of a variety of molecules, which increases the diversity of proteins that can be produced. Second, not all genes are expressed in all cells at the same time, meaning that different cells produce different sets of proteins. Third, many coding genes can be alternatively spliced, resulting in different mRNA transcripts that produce different proteins. Therefore, the ratio of the number of protein molecules to the number of genes is greater than 1. Finally, the total amount of protein in a cell, as measured by mass, is always greater than the total amount of DNA.