METABOLISMO BACTERIANO: RESPIRACION ANAEROBICA Y AEROBICA Y TODAS LAS FERMENTACIONES [6 MINUTOS]

Metabolism: Understanding Cellular Reactions

Overview of Metabolism

• Metabolism consists of a series of reactions in living cells that provide energy and nutrients necessary for life, growth, and reproduction. It includes two main processes: catabolism and anabolism.

• Catabolism breaks down nutrients to release energy, while anabolism utilizes this energy to synthesize new cellular materials such as proteins and nucleic acids.

Types of Cellular Respiration

• Anaerobic bacteria can perform fermentation, producing various gases or alcohol depending on the species. In contrast, facultative anaerobes or aerobes generate large amounts of ATP through oxidative phosphorylation.

• Glycolysis is the initial step in both aerobic and anaerobic respiration, crucial for all medically significant pathogens as it does not require oxygen.

Glycolysis Process

• Glycolysis oxidizes glucose into pyruvate while generating ATP and NADH; it occurs in the cytoplasm. Each glucose molecule (6 carbons) yields two pyruvate molecules (3 carbons each).

• In aerobic conditions, glycolysis is followed by the Krebs cycle where pyruvate is further oxidized to carbon dioxide and water. In anaerobic conditions, it converts into other products like lactate.

Cellular Respiration Mechanisms

• In prokaryotes, cellular respiration involves oxidation-reduction reactions linked to the electron transport chain located in the plasma membrane; in eukaryotes, this process occurs within mitochondria.

• The Krebs cycle produces carbon dioxide, ATP, NADH, and FADH2. Each NADH generates three ATP molecules during electron transport.

Oxygen's Role in Respiration

• Aerobic cells utilize oxygen as a terminal electron acceptor which combines with hydrogen ions to form water and carbon dioxide.

• Anaerobic cells use inorganic compounds instead of oxygen for respiration; different bacteria may utilize nitrates or sulfates as final electron acceptors.

Fermentation Processes

• Fermentation represents incomplete oxidation processes yielding energy from sugars or organic acids performed by obligate or facultative anaerobes.

• Lactic acid bacteria produce only lactic acid during fermentation while others may produce various acids or alcohol alongside lactic acid.

Products of Fermentation

• Ethanol produced by Saccharomyces is used in beverages and fuels; lactic acid from fermentation contributes to dairy products like cheese and yogurt.

• Different types of fermentation include alcoholic fermentation converting pyruvate into acetaldehyde then ethanol; oxidative fermentation results in acetic acid (vinegar).