Cold sores - painful sores on the lips and around the mouth, caused by a virus. Canker sores - painful sores in the mouth, caused by bacteria or viruses. Thrush - a yeast infection that causes white patches in your mouth. Leukoplakia - white patches of excess cell growth on the cheeks, gums or tongue, common in smokers.
Energy and Metabolism. All living organisms need energy to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is the set of life-sustaining chemical processes that enables organisms transform the chemical energy stored in molecules into energy that can be used for cellular processes.
Even rather similar enzymes can be found in all organisms. Energy comes from either chemical compounds or light. The word âautotrophismâ (Greek âautoâ = self, âtropheinâ = feed) means that the organism is able to obtain energy either from inorganic chemicals (chemotrophism) or from sunlight (phototrophism).