How is atp involved in cellular respiration? what would happen to cells of atp did not exist?

Could someone me with number one you

Hey me with this one❤❤❤❤ every organism needs food. does a cell also need it? explain very briefly.

With regard to enzymes, key is to lock as a) substrate is to activation energy eliminate b) product is to substrate. c) enzyme is to active site. d) substrate is to active site.