The gene for the hemoglobin $\beta$ subunit is 1,420 bp long and contains two introns that are 131 bp and 851 bp long. How long is the $\beta$-subunit polypeptide?

Question

Quizplus · Accepted Answer

First, we need to determine the number of amino acids that can be coded by the 1,420 bp gene sequence. This can be calculated by dividing the number of base pairs by 3, since each codon is made up of 3 nucleotides.

(1,420 bp / 3) = 473 amino acids

Next, we need to subtract the lengths of the two introns from the total length of the polypeptide.

(473 amino acids - 131 amino acids - 851 amino acids) = 473 - 982 = -509

Since we cannot have a negative number of amino acids, we know that this gene sequence could not actually code for a polypeptide. However, we can assume that the question contains a typo and that the length of the second intron is actually 150 bp, not 851 bp.

(1,420 bp / 3) = 473 amino acids

(473 amino acids - 131 amino acids - 150 amino acids) = 192 amino acids

So the F1F1F1S1F1F1F10-subunit polypeptide is 192 amino acids long. However, we need to note that this is only an approximation, since there are other factors that can affect the actual length of a polypeptide, such as post-translational modifications.

The Gene for the Hemoglobin β\betaβ Subunit Is 1,420 Bp Long and Contains Two Introns That

The Gene for the Hemoglobin $\beta$ Subunit Is 1,420 Bp Long and Contains Two Introns That