In this lesson, you’ll learn about the basics of cellular respiration. You’ll learn about the similarities and differences between aerobic and anaerobic respiration, which are the two main types of cellular respiration. Then, you can test yourself with a quiz.
What Is Cellular Respiration?
You wake up in the morning, get out of bed, and eat a nice big bowl of cereal. But how did your body get the energy to move your legs to even get out of bed? You know you need to eat to have energy, but how does your body make use of that food you eat? It all has to do with a little something called cellular respiration.
Cellular respiration is the process by which organisms turn food into a usable source of energy called adenosine triphosphate_(ATP). ATP is a molecule used to transport energy around an organism, whether that be a microscopic unicellular bacteria or a large multicellular animal like an elephant.Muscle cells, for example, cannot directly use food to move your legs. The cells must use ATP that is made from respiration to move those legs. ATP has three phosphate groups, and when the last group is broken off, it releases energy that cells can actually use. But not all respiration is the same. Your body can actually go through two types of respiration: aerobic and anaerobic.
Aerobic respiration is the more common type of respiration that occurs in the presence of oxygen. The chemical formula for aerobic respiration shows that glucose and water react to form the products: carbon dioxide, water, and ATP. This type of respiration produces 36 ATP molecules from one glucose molecule.
C 6 H 12 O 6 (glucose) + 6O 2 (oxygen) –> 6CO 2 (carbon dioxide) + 6H 2 O (water) + 36ATPAerobic respiration occurs in three steps:
- Glycolysis breaks down glucose into two smaller molecules called pyruvate
- The Krebs cycle, or the citric acid cycle, where the pyruvate molecules go through a series of reactions to release electrons
- The last step includes the electron transport chain in which electrons are used to create most of the 36 ATP
Anaerobic respiration is less common. It is the type of respiration that occurs when oxygen is not present. Anaerobic respiration produces only two ATP molecules from one glucose molecule. There are two main types of anaerobic respiration: alcohol fermentation and lactic acid fermentation.In alcohol fermentation, glucose is turned into carbon dioxide, ethanol, and ATP. Yeast goes through this process and is responsible for producing the alcohol in beer.
Yeast is also responsible for making the carbon dioxide that allows bread to rise.In lactic acid fermentation, glucose is turned into lactic acid, carbon dioxide, and ATP. This occurs in muscle cells and explains why we get sore after a hard workout. When you work too hard, your muscles cannot get enough oxygen and so you start producing lactic acid, which burns!
Cellular respiration turns food intro energy. It can happen in the presence of oxygen during aerobic respiration or without oxygen during anaerobic respiration.
Aerobic respiration is more common and produces 36 ATP, while anaerobic respiration produces 2. Alcohol and lactic acid fermentation are two types of anaerobic respiration.Aerobic respiration is when glucose and water react to form the products carbon dioxide, water, and ATP. Anaerobic respiration is either alcohol fermentation where glucose is turned into carbon dioxide, ethanol, and ATP; or lactic acid fermentation, where glucose is turned into lactic acid, carbon dioxide, and ATP.