Calculate the average molar concentration of a protein in a fibroblast. Assume a protein with 400 amino acids and estimate the number of gene products that are expressed in a human cell.

Answer 1

To calculate the average molar concentration of a protein in a fibroblast, we need to know the mass of the protein and the volume of the fibroblast.

First, let's assume that the average mass of an amino acid is approximately 110 Daltons (Da). The molecular weight of a protein with 400 amino acids would be:

Molecular weight of protein = 400 amino acids * 110 Da/amino acid = 44,000 Da

Next, we need to estimate the volume of a fibroblast. The volume of a human fibroblast can vary, but it's typically on the order of a few nanoliters (nL) to microliters (μL). For this example, let's assume the volume of a fibroblast is 1 picoliter (1 pL) or 1 x 10^-12 liters.

Now, we can calculate the average molar concentration of the protein in the fibroblast:

Average molar concentration = (Mass of protein) / (Volume of fibroblast) Average molar concentration = 44,000 Da / (1 x 10^-12 L) = 4.4 x 10^16 μM (micromolar)

So, the average molar concentration of the protein in a fibroblast is approximately 4.4 x 10^16 μM.

As for estimating the number of gene products that are expressed in a human cell, the human genome contains approximately 20,000 to 25,000 protein-coding genes. Each gene can give rise to multiple transcript variants through alternative splicing and alternative polyadenylation, resulting in various gene products.

The actual number of gene products expressed in a human cell is complex and difficult to determine precisely due to alternative splicing, post-translational modifications, and different isoforms. However, it is estimated that human cells may express hundreds of thousands to over a million different gene products, considering the various protein isoforms and modifications.