Macromolecules, though, are the most interesting and characteristic molecules of living systems; in a true sense the evolution of life as we know it is the evolution of macromolecular structures. Proteins, the workhorses of the cell, are the most abundant and functionally versatile of the cellular macromolecules. To appreciate the abundance of protein within a cell, we can estimate the number of protein molecules in a typical eukaryotic cell, such as a hepatocyte in the liver. This cell, roughly a cube 15 μm (0.0015 cm) on a side, has a volume of 3.4 × 10−9 cm3 (or milliliters). Assuming a cell density of 1.03 g/ml, the cell would weigh 3.5 × 10−9 g. Since protein accounts for approximately 20 percent of a cell’s weight, the total weight of cellular protein is 7 × 10−10 g. The average yeast protein has a molecular weight of 52,700 (g/mol), as noted in Chapter 3. Assuming this value is typical of eukaryotic proteins, we can calculate the total number of protein molecules per liver cell as about 7.9 × 109 from the total protein weight and the number of molecules per mole, which is a constant (Avogadro’s number). To carry this calculation one step further, consider that a liver cell contains about 10,000 different proteins; thus, a cell contains close to a million molecules of each protein on average. In actuality, however, the abundance of different proteins varies widely, from the quite rare cell-surface protein that binds the hormone insulin (20,000 molecules) to the abundant structural protein actin (5 × 108 molecules).
Thank you for the response but In your first response the answer for mass is 27pg but in the second one it is 3.5*10^-9g. These numbers are not compatible and way different from each other.
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