BOK 121 Lecture One PDF

BOK 121 energy Homeostasis(I) Dr. M Gamede [email protected] BMS building: Room No.7:13 Learning objectives ✓ Understand the basic concepts of nutrition and metabolism in relation to health and disease ✓ Know the basic process of metabolism and the extraction of energy (as ATP) from food...

BOK 121 energy Homeostasis(I) Dr. M Gamede [email protected] BMS building: Room No.7:13 Learning objectives ✓ Understand the basic concepts of nutrition and metabolism in relation to health and disease ✓ Know the basic process of metabolism and the extraction of energy (as ATP) from foodstuffs ✓ Assessment criteria ✓ Discuss the basic concepts of nutrition and metabolism in relation to health and disease ✓ Explain the basic process of metabolism and the extraction of energy (as ATP) from foodstuffs. Overview of nutritional energy Nutrition: Macronutrients and Micronutrients ✓ Carbohydrates(+- 45%): Primary source of energy. Broken down into glucose, ✓ used in cellular respiration to produce ATP ✓ Proteins (+- 15%): : Provide amino acids for building and repairing tissues. ✓ Can be used for energy if carbohydrates and fats are insufficient ✓ Fats (+- 30%): : Concentrated energy source. ✓ Broken down into fatty acids and glycerol for energy production or storage. ✓ Trace elements: Vitamins (A, B complex, C, D, E, K), and minerals ✓ Magnesium: is required as a catalyst for many intracellular enzymatic reactions, particularly those related to carbohydrate metabolism. Trace elements: Minerals Digestive Process ✓ Ingestion: Intake of food. ✓ Digestion: Breakdown of food into smaller molecules by enzymes. ✓ Absorption: Nutrients absorbed into the bloodstream from the digestive tract. ✓ Assimilation: Incorporation of absorbed nutrients into body cells. Cellular Respiration ✓ Glycolysis (cytoplasm) :Breaks down glucose into pyruvate, producing a small amount of ATP and NADH ✓ Krebs Cycle or Citric Acid Cycle(mitochondria): Processes pyruvate into CO2, producing ATP, NADH, and FADH2 ✓ Oxidative Phosphorylation( inner mitochondrial membrane): Uses NADH and FADH2 to produce a large amount of ATP through the electron transport chain and chemiosmosis NADH-nicotinamide adenine dinucleotide (NAD) + hydrogen (H) ; FADH2-Flavin adenine dinucleotide Electron transport chain-ATP genaration ATP as energy source ✓ ATP regenerated from ADP + Pi when fuel molecules are oxidised ✓ ATP is a nucleotide: adenine – ribose – triphosphate ✓ Active form of ATP usually a complex with Mg2+ ✓ Energy rich molecule because it contains 2 phospho- anhydride bonds (high energy bonds from which a large amount of free energy is liberated when ATP is hydrolyzed) ✓ ATP – ADP cycle is the fundamental mode of energy exchange in biological systems ✓ ATP + H2O → ADP + Pi ΔG°´ = -7.3 kcal/mol ✓ ADP + H2O → AMP + Pi ΔG°´ = -6.6 kcal/mol ✓ AMP + H2O → adenosine + Ppi ΔG°´ = -3.4 kcal/mol Gibbs free energy calculation ✓ Energy: at the heart of metabolism ✓ Each reaction has a FREE ENERGY component ✓ Catabolic reaction: releases energy ✓ Anabolic reaction: requires energy ΔG: CHANGE IN FREE ΔS: CHANGE IN ENERGY ΔG = ΔH - TΔS ENTROPY Energy available to do work. measure of the Predicts whether a reaction is change in disorder favourable. ΔH: CHANGE IN ENTHALPY T: REACTION TEMP Heat released or absorbed Temperature in which during a reaction reaction takes place Metabolism ✓ Anabolic Pathways: Pathways that build complex molecules from simpler ones ✓ Protein Synthesis: Building proteins from amino acids. ✓ Glycogenesis: Formation of glycogen from glucose. ✓ Lipogenesis: Formation of fat from glucose and fatty acids. ✓ Catabolic Pathways: Pathways that break down complex molecules into simpler ones, releasing energy ✓ Glycolysis: Breakdown of glucose into pyruvate ✓ Beta-Oxidation: Breakdown of fatty acids into acetyl-CoA ✓ Proteolysis: Breakdown of proteins into amino acids Energy Storage ✓ Glycogen: Stored in the liver and muscles ✓ Provides a readily available source of glucose for short-term energy needs. ✓ Adipose Tissue: Distributed throughout the body, especially under the skin and around organs ✓ Stores triglycerides for long-term energy reserves ✓ Muscle Protein: Found in skeletal muscles ✓ broken down into amino acids and used for energy in extreme conditions. Energy Storage Process ✓ Lipogenesis: Conversion of glucose and amino acids into fatty acids for storage in adipose tissue. ✓ Glycogenesis: Conversion of glucose into glycogen for storage in the liver and muscles. Hormonal Regulation ✓ Insulin: Promotes glucose uptake and storage, protein synthesis, and fat storage ✓ Glucagon: Stimulates glycogen breakdown and glucose release from the liver ✓ Adrenaline (Epinephrine): Increases glycogen breakdown and fat mobilization ✓ Thyroid Hormones: Increase basal metabolic rate and enhance overall metabolism Energy Balance ✓ Positive Energy Balance: Energy intake exceeds expenditure, leading to weight gain. ✓ Negative Energy Balance: Energy expenditure exceeds intake, leading to weight loss. ✓ Homeostasis: The body’s ability to maintain a stable internal environment, crucial for overall health. Metabolic Adaptations ✓ Fed State: After eating, insulin levels rise, promoting glucose uptake and storage, protein synthesis, and fat storage. ✓ Fasting State: Glucagon levels rise, promoting glycogen breakdown, glucose release, and fat mobilization for energy. ✓ Starvation: Prolonged fasting leads to muscle protein breakdown for energy, ketosis from fat breakdown, and reduced metabolic rate to conserve energy. Obesity(metabolic disease) Obesity is a medical condition characterised by an excessive accumulation of body fat Causes: Environmental Factors, Chronic Medications and Hormonal Imbalances Diagnosis: Body Mass Index (BMI) and Blood Tests Treatments: Appetite Suppressants and Fat Absorption Inhibitors Diabetes mellitus (metabolic diseases) ✓ Diabetes is a chronic medical condition characterized by elevated levels of glucose (Type one, type two or gestational diabetes) ✓ Causes: Poor diet, lack of physical activity, and obesity ✓ Diagnosis: Oral Glucose Tolerance Test (OGTT) and HbA1C Test ✓ Treatments: Lifestyle modification, Insulin Therapy, insulin sensitizers(metformin) Thank You