module 3 - metabolic pathways

Cellular Fuel and Metabolism

• Glucose is the primary cellular fuel essential for survival.
• Oxidative phosphorylation occurs in the mitochondria, where ATP is produced through electron transport and chemiosmosis.

Waste Products and Enzyme Inhibition

• The citric acid cycle excretes carbon dioxide and water as waste products.
• Competitive inhibitors bind to the active site of an enzyme, competing directly with the substrate for binding.
• Competitive inhibitors do not affect Vmax but can increase Km, indicating a higher substrate concentration is required to reach half Vmax.

Nerve Gas and Metabolic Pathways

• Nerve gas functions primarily as an irreversible inhibitor of acetylcholinesterase, disrupting neurotransmission.
• Objectives of metabolic pathways include energy production, biosynthesis, and regulation of metabolic flux.
• Characteristics of metabolic pathways typically involve being regulated by enzymes and being interconnected.

Glycolysis and Metabolic Regulation

• A product of glycolysis is pyruvate, which can further undergo fermentation or enter the citric acid cycle.
• The net reaction for glycolysis is the conversion of glucose into two molecules of pyruvate, yielding two ATP and two NADH.
• Mechanisms NOT used by cells for regulating metabolism include random changes in metabolic rates without feedback.

Genetic Diseases and Compartmentalization

• Phenylketonuria (PKU) is an example of a genetic disease that impacts metabolism due to enzyme deficiencies.
• Compartmentalization in metabolism can be exemplified by the presence of mitochondria and their role in energy metabolism.

Glycogenesis, Lipolysis, and Fatty Acid Dynamics

• Glycogenesis, the synthesis of glycogen from glucose, occurs primarily in liver and muscle cells during insulin response.
• Lipolysis involves the breakdown of triglycerides into glycerol and free fatty acids, primarily stimulated by hormones during fasting or stress.
• Lipogenesis refers to the conversion of excess carbohydrates into fat, occurring mainly in the liver and adipose tissue through insulin signaling.
• Fatty acid oxidation is the metabolic pathway where fatty acids are broken down in the mitochondria to produce acetyl-CoA, which enters the citric acid cycle.

Test your knowledge on important metabolic pathways, including glycogenesis, the Krebs/citric acid cycle, and oxidative phosphorylation. Learn about the conversion of glucose to glycogen, the production of building blocks for biosynthesis, and other vital concepts. Perfect for preparing for exams!