What are check points and why are they important in the cell cycle

Hmm this is a rough explanations but because to be sure cells are made properly and not misfunctioning or going Rouge.

Cancer cells is an example of this, a cell goes rouge and starts doing it's function on it's own but outside of it's brother cells function slightly different turning into a growth or etc. The body thinks it is normal during the check body it's composed of the dna that passes this check.

viruses and other things don't pass this check and things like white blood cella come shut it down.

that's why doctors poison the area they find the cancer. to send white blood cells there to shut the area down not passing the check.

Mitochondria is the cell organelle that produced the energy that is needed in the body system in form of atp, that is why it is called the power house of the cell. energy is needed by the living organisms to carry out the activities which sustain life.  if the mitochondria is destroyed atp will not be produced. if the mitochondria is destroyed, energy production will stop and the affected living organism will not have the energy to carry out the necessary life processes; this will lead to the death of the organism.

Single strand binding protein by peptide bond