Why do you think air and food are important to staying alive?
Air contains many gases, however, oxygen is necessary to keep aerobic heterotrophic organisms alive. It is needed for the process of cellular respiration. Food contains nutrients such as glucose, amino acids and fatty acids as well as vitamins and minerals. Glucose is utilized in cellular respiration as an energy source. Inside the cell are organelles called mitochondria. In the mitochondria, respiration occurs. Glucose combines with oxygen chemically with the help of respiratory enzymes and three products form. Carbon dioxide and water vapor which are waste products that you excrete each time you exhale. However, 1 molecule of glucose yields 36 molecules of adenosine triphosphate or A.T.P. This high energy molecule keeps cells alive. Food also contains vitamins which assist enzymes in their activities and are known as coenzymes. A vitamin deficiency can result in a serious health problem. An example is a lack of vitamin C leads to scurvey. This condition weakens blood vessels and leads to bleeding. Minerals are needed for various organs to function. For example, calcium is needed for bones to remain strong and healthy. Therefore, not only do aerobic heterotrophic organisms need a supply of air containing oxygen, we need food to provide fuel. To contrast, autotrophic organisms, like plants, need carbon dioxide which again can be found in the air. This gas is necessary for plants to carry out photosynthesis. This process, in turn produces glucose, which is a food which plants can store for later use for energy and they also produce oxygen and water vapor.