How do we die?

[loveangel]

andrew, if you doubt about it, what's the truth?

[MrMistery]

cell division in most human cells is calibrated to complete a certain number of times. that is because the telomeres keep shortening. but in the cells that divide continuously the telomerase enzyme is expressed that eliminates this problem. so saying that our body is programmed to divide for x number of times is a poorly understood afirmation by the person saying it.

If you ask me of course...

[Locus]

I think that central reason for aging and dearth is mutation that accumating at the somatic cels and destroy by the time our body, so we die. But also, there is (possibly) a prorammed element of the dearth, such telomerloss at the some cells. But why it is develop at the evolution? For control by the cells?

[MrMistery]

well the problem of telomeres is intrinsec to all organisms with linear DNA. Sure, the telomerase enzyme could be activated in all our cells, but what would be the point? not all our cells need to divide that intensily. second, death is necessary in order for genetic variation to occur.

[sachin]

I think that central reason for aging and dearth is mutation that accumating at the somatic cels and destroy by the time our body, so we die.

I m partly agree with you;

it is observed (scientific proof) that; elder couple if ve child in late ages as 40-45, there are more chances that the child may have more genetic dissorders....

[Locus]

second, death is necessary in order for genetic variation to occur.

Variation? why? If individuals will be immortal (not aging) there is will not evolution, but there is inpossible to be completly immortal for living object becouse at the world is much more reasons to die than to live . So, it is meanless direction of evolution that directed to dearth of individuals for generation of genetic variation.

well the problem of telomeres is intrinsec to all organisms with linear DNA. Sure, the telomerase enzyme could be activated in all our cells, but what would be the point? not all our cells need to divide that intensily.

But each cel contein gene for telomerase, why it is not activated in some of cells??? It is march more "easy" for organism to activate gene at the al of cell that only at the defined part of them, so mechanis for this must exist and had been preferable at the evolution process. I think that reasons for that is likely (in meaning of meintenence of whole struture - organism or nest) reasons that make workes of social insects is infertile.

[MrMistery]

i don't get what social insects have to do with telomerase. Ok, so it's like this: all of the cells of a multicellular organism have all the genes. But only some of the genes express in each cell. It is not worth it to express the telomerase enzyme in all of the cells because the enzyme is not needed in all of the cells. What point would it be for it to express in neurons? Muscle cells? Bone cells? Most cells in the oranism specialise and stop divinding. Because of that, the enzyme in these cells would be simply a waste of amino acids.
And no, it is not easier to activate the gene in all of the cells. Because eukaryotic genes do not work like bacterial genes. You need the activator to be present in order for the enzyme to be produced. And the activator is a protein. So that would mean more energy spent for making the activator. Evolution practices economy in its strictest sense possible...

[Locus]

Energy that needed for sintesis of the protein is not always critical pin for evolution. And, also, genes must have stronge promoter for expression without of activators. (realy, I don't know if it's completly possible, or any activators that bind to enchsers also needed)
Social insect workes I compare with the cells of multicellular organism.

[MrMistery]

not always, but in general. name one situation where something evolved wasting energy. there aren't many.

strong promoter? what's that? sorry but i really don't understand... How can a gene be activated in the absence of activators?

[sachin]

not always, but in general. name one situation where something evolved wasting energy. there aren't many.

That means you belive there are......

[Locus]

strong promoter? what's that? sorry but i really don't understand... How can a gene be activated in the absence of activators?

It is promoter that bind with strong affinity the polymerase. When do genetic engenirien on the eukariotes there is no why than to use by sach promoters, but those promoters can be viral...

[MrMistery]

could you rephrase, i don't understand. maybe it is a translation problem

@sachin
in biology there is no proving the no answer. There might be, but as the exception, not the rule.