The substance that helps keep the integrity of the bacterial cell wall intact is known as the peptidoglycan. Others also refer to is it as murein or mucopeptide. The bacterial cell wall is necessary for survival because of the high internal pressure present inside of bacteria. Under normal conditions, if the cell wall is removed the bacterial cell will burst.
The peptidoglycan is a layer that can be used to distinguish gram positive bacteria from gram negative ones. G(+) bacteria have a thick layer of this while G(-) have a thinner ones.
Aerobic respiration is far more energy-efficient than anaerobic respiration. Aerobic processes produce up to 38 ATP per glucose. Anaerobic processes yield only 2 ATP per glucose