What effect does earths spherical shape have on the amount of sunlight to reach the equator

Because of the way the earth goes around the sun (on its tiled axis) and because that part of the earth is closer to the sun (because the earth is round) the closer you are to the equator the warmer it is.

Mitochondria produce atp, a high energy compound. atp is used for all sorts of enzyme-mediated reactions, such as making proteins/nucleotides/etc, certain compounds cross the cell membrane, muscles move, etc.  without this source of energy, a cell will die. it will not be able to repair itself, defend against pathogens, etc.