Middle School Life Science: Prokaryotes - Introduction to Prokaryotes — Flashcards

Like all living things, prokaryotes need energy and carbon. They meet these needs in a variety of ways and in a range of habitats.    
Prokaryotes may have just about any type of metabolism. They may get energy from light or from chemical compounds. They may get carbon from carbon dioxide or from other living things. Most prokaryotes get both energy and carbon from other living things. Many of them are decomposers. They break down organic wastes and remains of dead organisms. In this way, they help to recycle carbon and nitrogen through ecosystems. Some prokaryotes use energy in sunlight to make food from carbon dioxide. They do this by the process of photosynthesis.    
They are important producers in aquatic ecosystems.    
Prokaryotes live in a wide range of habitats. For example, they may live in habitats with or without oxygen.    
Prokaryotes that need oxygen are described as aerobic. They use oxygen for cellular respiration. Examples include the prokaryotes that live on your skin. Prokaryotes that don't need oxygen or are poisoned by it are described as anaerobic. They use fermentation or other anaerobic processes rather than cellular respiration. Examples include many of the prokaryotes that live inside your body.    
Like most other living things, prokaryotes also have a temperature range that they “like” best. Thermophiles are prokaryotes that prefer a temperature above 45 °C (113 °F). They might be found in a compost pile. Mesophiles are prokaryotes that prefer a temperature of about 37 °C (98 °C). They might be found inside the body of an animal such as you. Psychrophiles are prokaryotes that prefer a temperature below 20 °C (68 °F). They might be found deep in the ocean.