On average, how many cells divide each day in a human being? How long does a cell wait before dividing itself ?
I have tried to look on the internet but surprisingly the answer is difficult to find..
My first thought was this:
According to Wikipedia (citation provided)
For every cell that dies a new one must be born, so there must be at least between 50 and 70 billion cell divisions to replenish these cells in an adult human (no net growth).
But then I remembered erythrocytes. Wikipedia again:
So approximately 1% of erythrocytes are destroyed every day and must be replaced. That's 2-3 x 1011 cells formed every day, which dwarfs the cells replenished due to apoptosis (5 - 7 x 109).
100kg human = 1kg dna = 50g telomeres (where 100kgMice=1kgDNA=100gTelomeres), Human average telomeres are ~15KB, so we simply calculate 15000/100= 150bp = 1%, so we lose 1% of our telomeres per division. So humans' cells must have about 100 divisions per life time. Thus human Cells Divide on average (considering different tissue types differ in division rates, frequencies, etc): - twice a year. If thats the case, then all cells of humans are replaced over 50years or longer, or not at all, and just the old cells (with shortened telomeres) percentage is increasing till death cascades win totally. - Or Telomerase Doesnt twice a year (on average per life time). In a case, where telomerase has errors/etc , in which case, better telomerases (with less errors/etc) humans will live longer. And that would mean that the rate of new cells replacing old cells is less, but still around 3times/year/cell. But then why would over life time length increase. Thus this option is NOT the case! - Or each day, thus All Cells Die 3 times a Year, as if each cell divides every 24h. This would mean that we increase weight 3times a year, Or in other words, going through complete metamorphosis 3 times a year. This would mean that the overall rate of new cells changing old cells is 3 times/year/cell. But if thats was the case, then why would telomeres decrease with age. Thus this option is NOT the case!