Given that the distance between two nucleotides in DNA is 0.3 nanometers, what is the length of the DNA in a human sperm cell? What is the average size (number of amino acids) of a human protein (please give reference)?
2006-09-20 00:32:07 · 1 answers · asked by * 1 in Science & Mathematics ➔ Other - Science
If you added up all the base pairs from all the different chromosomes, you'd find that there are approximately 3 billion of them. A normal cell would have about two copies of all those base pairs (one from each parent, of course), but a germ cell has only one. If the distance between two nucleotides is 0.3 nm and you could line up all the DNA end to end, that works out to 0.9 meters of DNA.
It is estimated that there are 20-25 thousand genes in all that DNA, and that 98.5% of the DNA is junk (exons which don't code for anything). This means that only 30 million of those base pairs are doing anything, and that they code for about 22 thousand genes. That means that on average each gene is about 1364 base pairs long. We also know that each codon for an amino acid is three base pairs in length, so if we assume that all that DNA is actually translated into amino acids (not a great assumption, but we're dealing with averages here) than you end up with an average protein being about 455 amino acids long.
Hope that helps! Link for reference below:
2006-09-20 11:30:11 · answer #1 · answered by Doctor Why 7 · 0⤊ 0⤋