Chapter 7 Flashcards
Energy
Energy and Metabolism Basics
Energy: Capacity to perform work in various forms—heat, mechanical, electrical, and chemical.
Metabolism
Energy and Metabolism Basics
Metabolism: Total chemical reactions in living cells.
Energy metabolism includes all reactions used to extract and use energy from food.
Liver cells
Cellular Metabolic Processes
Liver cells: Most metabolically active, essential for various metabolic reactions.
Anabolism
Cellular Metabolic Processes
Anabolism: Small molecules combine to form larger ones, consuming energy.
Catabolism
Cellular Metabolic Processes
Catabolism: Large molecules break down, releasing energy.
ATP
Energy Transfer with ATP
ATP (Adenosine Triphosphate): High-energy compound crucial for cellular activities. Contains three phosphate groups, with energy released when bonds break.
Coupled reactions
Energy Transfer with ATP
Coupled reactions: Energy is consumed and produced simultaneously in the body, with some lost as heat.
Enzymes
Metabolic Helpers
Enzymes: Protein catalysts aiding reactions without being altered.
Coenzymes
Metabolic Helpers
Coenzymes: Organic molecules (often B vitamins) that help enzymes function properly.
Carbohydrates
Nutrient Breakdown for Energy
Carbohydrates: Digested into glucose/monosaccharides.
Fats
Nutrient Breakdown for Energy
Fats: Broken down into glycerol and fatty acids.
Proteins
Nutrient Breakdown for Energy
Proteins: Broken into amino acids, supporting both energy production and storage.
Glycolysis
Energy-Yielding Pathways
Glycolysis: Glucose splits into two pyruvate molecules, leading to energy release.
Pyruvate to Lactate (Anaerobic): Fast energy release without oxygen. Pyruvate to Acetyl CoA (Aerobic): Slower, oxygen-requiring pathway that feeds into the TCA cycle.
Fatty Acid Oxidation
Energy-Yielding Pathways
Fatty Acid Oxidation: Fatty acids yield acetyl CoA, with hydrogen and electrons transported to the electron transport chain.
Amino Acid Metabolism
Energy-Yielding Pathways
Amino Acid Metabolism: Amino acids must undergo deamination to enter energy pathways, becoming pyruvate or acetyl CoA.
TCA Cycle
TCA Cycle and Electron Transport Chain
TCA Cycle: Circular process within mitochondria, crucial for energy production, involving oxaloacetate.
ETC
TCA Cycle and Electron Transport Chain
Electron Transport Chain (ETC): High-energy ATP synthesis; oxygen accepts electrons, forming water.
Feasting
Feasting vs. Fasting
Feasting (Excess Energy): Excess nutrients, especially fat, are stored post-meal.
Fasting
Feasting vs. Fasting
Fasting: Glycogen and fat stores provide energy initially, but prolonged fasting depletes glycogen, using body proteins for glucose. Hormones slow metabolism to conserve energy.
Gluconeogenesis
Adaptations to Fasting
Gluconeogenesis: Formation of glucose from non-carbohydrates (e.g., amino acids).
Ketosis
Adaptations to Fasting
Ketosis: Produces ketone bodies as alternative fuel for the brain, decreasing protein breakdown and inducing appetite loss.
Physical
Starvation Symptoms
Physical: Muscle wasting, reduced heart and metabolic rates, low body temperature, impaired vision, organ failure.
Psychological
Starvation Symptoms
Psychological: Depression, anxiety, food-centered thoughts.
Low-Carb, Ketogenic Diet Side Effects
Potential side effects include nausea, fatigue, constipation, low blood pressure, elevated uric acid, bad breath, and risks for pregnant women (fetal harm).
