Can cells that carry on aerobic respiration operate anaerobically if needed?

Answer 1

Cells can usually make up for a lack of oxygen to produce energy with anaerobic respiration. For example, when doing heavy physical exercise like lifting weights (i.e. anaerobic exercise), the amount of energy required of the muscle cells exceeds the amount the cells are able to make through aerobic respiration given the amount of oxygen they get. So they compensate by using anaerobic respiration (glycolysis and fermentation of pyruvic acid) to produce that extra ATP. However, the byproduct of this anaerobic respiration, lactic acid, accumulates in the cells and body and is toxic. It has to be processed and broken down by the liver (when it accumulates in the muscles, for example, it causes muscle aches after exercise). So most animal cells cannot survive indefinitely solely on anaerobic respiration, but can supplement their energy generation with it if necessary.

Answer 2

Yes, cells that typically carry out aerobic respiration can switch to anaerobic respiration in the absence of oxygen. This allows them to continue generating ATP, though at a lower efficiency. Anaerobic respiration usually involves processes like fermentation to produce energy.

Answer 3

If they require oxygen they can not survive. No more that you can without oxygen. We are what is called an obligate aerobe.That means we have to have oxygen.