i know that cell dies due to lack of energy,when it doesn't get enough oxygen,bot exactly HOW does it gets killed?does it get temporarily shutdown,or get damaged?plz tell me

well, it depends on the cell.

 

SOME cells will go into a kind of hibernation when you starve them and re-awaken when conditions are more favourable.

 

others, will chug along till they die.

 

the cause of death is actually surprisingly complex and will vary from cell to cell. ultimately, there are certain functions a cell has to carry out to maintain its life, mostly repairing damage that naturally accumulates and replenishing chemicals it uses up to keep active. if there are no resources to repair itself then it will die because of accumulated damage and if it cannot replenish certain chemicals it will die because it cannot maintain a chemical equilibrium in itself.

 

then you have to factor in the whole 'what is alive?' factor because at the cellular level it starts getting a bit fuzzy.

Death is a complicated thing, and I don't think anyone knows quite the difference between alive and dead. Most cells need constant maintenance, and without it they would become irreparably damaged. Some cells can go into a resting state where they can stay dormant for thousands or perhaps millions of years... but revive when given water and nutrients.

thinking about damage,maintenance,repair,i am a bit confused.what actually is death?

Death is irreparable damage to an entity that causes the permanent cessation of its activity. At least that seems to be the general idea.

 

Once upon a time, cessation of breathing and heartbeat was considered death. Now we have CPR. The point at which something is considered dead thus depends upon our technology.

For individual cells it is fairly easy to answer. The moment they are not able to sustain their membrane potential, they die. Integral to a cell is a separation of their cytoplasm with their surrounding. Once that is compromised, it cannot recover anymore.

"The moment they are not able to sustain their membrane potential, they die.".......does this mean,if i could maintain potential somehow,a cell could live forever?

No, it only means that a cell that is still maintaining its membrane potential is still alive. Membrane functions are just an indicator of cell viability, not the sole cause.

"Death is irreparable damage to an entity that causes the permanent cessation of its activity"

 

IF we make out some way to repair all the damage and keep healing the cell,we can defeat death??