CELLULAR RESPIRATION I. Cellular Energy Food contains usable energy. Much of the energy is stored in proteins, carbohydrates, and fats. But before you can use it, it must be transferred to ATP through a process called cellular respiration. aerobic respiration – metabolic process that requires oxygen anaerobic respiration – metabolic process that does not require oxygen

II. Cellular Respiration Cellular respiration is the process cells use to harvest the energy in organic compounds, particularly glucose. enzymes C6H12O6 + 6O2 6CO2 + 6H2O + ATP glucose

Stages of Cellular Respiration: Stage 1: Breakdown of Glucose The primary fuel for cellular respiration is glucose (C6H12O6).

Glycolysis – the break down of glucose in the cytoplasm; glycolysis uses 2 ATP but produces 4 ATP for a total net gain of 2 ATP and pyruvate

Stage 2: Production of ATP When oxygen is present pyruvate produced by glycolysis enters a mitochondria and is converted into ATP through a series of enzyme-assisted chemical reactions.

Cellular Respiration Stage 2 – Mitochondria Stage 1 - Cytoplasm *O2 is needed Stage 1 - Cytoplasm

Two types of Fermentation: Fermentation – occurs when O2 is not present Two types of Fermentation: 1. lactic acid fermentation – during vigorous exercise pyruvate in muscle cells is converted to lactate; lactate or lactic acid can build up causing muscle soreness. 2. alcoholic fermentation – pyruvate is broken down into ethanol, this occurs in the preparation of food and beverages (wine, beer, and bread dough)

Summary of Cellular Respiration Production of ATP Glycolysis 2 ATP 2 ATP *aerobic *anaerobic 34 ATP 0 ATP Total 36 ATP Total 2 ATP Oxygen present Oxygen not present

Cellular Respiration Enters mitochondria Up to 2 ATP

Which metabolic process is shown at letter B?