Aerobic respiration needs oxygen. The glucose is broken down completely, so the products are carbon dioxide and water and a large yield of ATP. Aerobic respiration releases more ATP than anaerobic respiration. Glucose + oxygen → carbon dioxide + water.
Anaerobic respiration happens when there is no oxygen, for example in muscles during hard exercise or in yeast in a sealed jar. The glucose is only partly broken down, so much less ATP is made than in aerobic respiration.
The products depend on the organism. In animals, glucose is turned into lactic acid: glucose → lactic acid. Lactic acid builds up in muscles during hard exercise. In plants and fungi such as yeast, glucose is turned into ethanol and carbon dioxide: glucose → ethanol + carbon dioxide. This is called fermentation and it is used in baking and brewing. The bubbles in a yeast and sugar mixture are carbon dioxide.