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.

Let's assume the average mass of an amino acid is approximately 110 Da (Daltons). 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 μL (1 x 10^-6 L).

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^-6 L) = 44,000 μM (micromolar)

So, the average molar concentration of the protein in a fibroblast is approximately 44,000 μM.

As for estimating the number of gene products 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, leading to various gene products. It is challenging to provide an exact number of gene products expressed in a human cell due to alternative splicing and post-translational modifications, which can significantly increase protein diversity.

However, it's safe to say that the number of gene products expressed in a human cell is considerably higher than the number of protein-coding genes in the human genome, likely reaching hundreds of thousands to millions of different gene products.