7.1 - Energy Production through Cellular Respiration

The Necessity of Energy in Metabolic Processes

• Catabolism releases energy.
• Anabolism uses energy.
• Without energy, anabolic processes such as the formation of proteins—the basic materials of muscles—cannot occur.
• Cellular respiration produces energy for the activities of all living cells.

Main Substrate in Energy Production

• Cellular respiration is the oxidation of organic molecules through several stages to release energy.
• Glucose is the main substrate for cellular respiration; its chemical energy is released for use by cells.
• Humans and animals obtain glucose through the digestion of carbohydrates from food.
• Green plants produce glucose through photosynthesis when chlorophyll traps light energy.

Types of Cellular Respiration

• Aerobic respiration occurs in the presence of oxygen.
• Anaerobic respiration occurs without oxygen.
• Fermentation is an alternative pathway for obtaining energy. Glucose is broken down incompletely when oxygen is limited or absent.