UNIT 12 CS 40-42 BASIC CONCEPTS OF METABOLISM Prepared by: Mr. Norman P. Gutierrez, RN, MAN 26TH November 2012

Learning Objectives Define anabolism, catabolism and metabolism. Explain electoral transport chain. Explain source of energy extracted from metabolic fuel. Prepared by: Mr. Norman 9/16/2018

Learning Objectives Explain the source of energy extracted from food. Explain the biomedical importance of metabolism. Describe carbohydrate metabolism. Prepared by: Mr. Norman 9/16/2018

Learning Objectives Describe lipid metabolism. Describe amino acid metabolism. Explain the interrelationship in the metabolism of proteins, lipids and carbohydrates. Prepared by: Mr. Norman 9/16/2018

DEFINITION OF TERMS CATABOLIC ANABOLIC Break down complex molecules such as proteins, polysaccharides and lipids to a few simple molecules like CO2, NH3 and H20 ANABOLIC Forms complex end products from simple precursor Smaller molecules are used to synthesize big and complex molecules Prepared by: Mr. Norman 9/16/2018

DEFINITION OF TERMS METABOLSIM Is the total chemical changes taking place in the cell. Prepared by: Mr. Norman 9/16/2018

Source of Energy Comes from high energy compounds Key compound: Adenosine triphosphate (ATP), hydrolysis of ATP to ADP (adenosine diphosphate) and inorganic phosphate (7,600 cal/mol) ATP supply in the body is limited Body changes ADP back to ATP by adding high energy phosphate group to ADP (phosphorylation) Prepared by: Mr. Norman 9/16/2018

ELECTRON TRANSPORT CHAIN Series of Reactions Passes electron to oxygen Glucose & Fatty acids Are metabolized by OXIDATION CO2 + H2O NAD FAD NADH and FADH Prepared by: Mr. Norman 9/16/2018

ELECTRON TRANSPORT CHAIN Electron passed ETC Lose much of free energy Captured and stored by ATP production (ADP + Pi) Oxidative phosphorylation Limited to Mitochondrion Final common pathway by which electrons derived form different fuels of the body flow to oxygen!

EXTRACTION OF ENERGY FROM METABOLIC FUELS From food via oxidation (CO2+H2O) 1st stage: Metabolic fuels (CHO, COOH & CHON) are hydrolysed to their monomeric building blocks 2nd stage: Building blocks are degraded to various pathways to a common metabolic intermediate, ACETYL CoA 3rd stage: Citric acid oxidizes acetyl CoA to CO2 ---C-C & C-H = NADH+FADH2 Final Stage Extraction from oxidative phosphorylation Electron pairs of NADH & FADH2 via ETC – used to synthesize ATP Prepared by: Mr. Norman 9/16/2018

EXTRACTION OF ENERGY FROM METABOLIC FUELS From food via oxidation (CO2+H2O) 1st stage: Metabolic fuels (CHO, COOH & CHON) are hydrolysed to their monomeric building blocks 2nd stage: Building blocks are degraded to various pathways to a common metabolic intermediate, ACETYL CoA 3rd stage: Citric acid oxidizes acetyl CoA to CO2 ---C-C & C-H = NADH+FADH2 Final Stage Extraction from oxidative phosphorylation Electron pairs of NADH & FADH2 via ETC – used to synthesize ATP Prepared by: Mr. Norman 9/16/2018

EXTRACTION OF ENERGY FROM METABOLIC FUELS Carbohydrates Protein Lipids Stage I Hydrolysis of metabolic fuels to their building blocks Glucose Amino Acids Fatty Acids Stage II Conversion of building Blocks to acetyl CoA Acetyl CoA CITRIC ACID CYCLE Stage III Oxidation of acetyl CoA Stage IV Oxidative Phosphorylation 3NADH & FADH2 2CO2 O e- ETC e- H2O Prepared by: Mr. Norman ADP + Pi ATP 9/16/2018

BIOMEDICAL IMPORTANCE OF METABOLISM Provides a sound understanding of many diseases Variations and adaptations due to starvation, exercise, pregnancy and lactation are included in normal metabolism Abnormal metabolism results from nutritional deficiency, enzyme deficiency and excessive secretion of hormones Diabetes mellitus is an example of disease caused by abnormal metabolism Prepared by: Mr. Norman 9/16/2018

CARBOHYDRATE METABOLISM Pyruvate and lactate are formed in the mammalian cells as a result of oxidation of glucose by glycolysis. In the absence of oxygen , glycolysis occurs in the cytoplasm of the cells producing lactate only. Under aerobic conditions pyruvate is metabolized to acetyl CoA which enters citric acid cycle for complete oxidation to CO2 and H2O. Prepared by: Mr. Norman 9/16/2018

CARBOHYDRATE METABOLISM Glucose also takes part in other metabolic processes: It is converted to glycogen for storage particularly in liver and skeletal muscles. The HMP shunt or pentose phosphate pathway arriving from intermediates of glycolysis is a source of reducing equivalents (2H) for biosynthesis of fatty acids, cholesterol, etc. and is a source of ribose which is required for nucleic acids formation. Prepared by: Mr. Norman 9/16/2018

CARBOHYDRATE METABOLISM Glucose also takes part in other metabolic processes: Triose phosphate of glycolysis is a source of glycerol of fat. Pyruvate and intermediates of TCA cycle form amino acids and cholesterol, the precursor of all steroid hormones in the body. Prepared by: Mr. Norman 9/16/2018

LIPID METABOLISM The long chain fatty acids are synthesized from acetyl CoA derived from CHO or from dietary lipids. In the tissues, fatty acids are oxidized to acetyl CoA or esterified to acyl glycerol to form fat which is the main calorie reserve of the body. Prepared by: Mr. Norman 9/16/2018

LIPID METABOLISM Acyl CoA formed by the β oxidation has the following significant roles in the body: It liberates CO2 and H2O and also yields high energy. It is a source of cholesterol biosynthesis. In liver it forms ketone bodies which are alternate water soluble tissue fuels. (this fuels become important sources of energy) Prepared by: Mr. Norman 9/16/2018

AMINO ACID METABOLISM Amino acids are required for protein synthesis. The essential amino acids must be supplied in diet since they are not synthesized by the tissues. Diet can supplement non-essential amino acids which are also formed from the intermediates of citric acid cycle by transamination. Prepared by: Mr. Norman 9/16/2018

AMINO ACID METABOLISM Excess amino nitrogen as a result of deamination give the following products: CO2 and H2O via citric acid cycle. Glucose by gluconeogenesis. Ketone bodies. Amino acids are precursors of many other important compounds like purines, pyrimidines and hormones such as epinephrine and thyroxine. Prepared by: Mr. Norman 9/16/2018

INTER-RELATIONSHIP IN THE METABOLISM OF PROTEINS, LIPIDS & CARBOHYDRATES GLUCOSE Glycerol thru triosephosphate and acetyl CoA thru pyruvate. ACETYL CoA helps the formation of fatty acids with malonyl CoA. GLYCEROL and FATTY ACIDS combine to form TRIACYLGLYCEROL (neutral fat). Prepared by: Mr. Norman 9/16/2018

INTER-RELATIONSHIP IN THE METABOLISM OF PROTEINS, LIPIDS & CARBOHYDRATES KETOACIDS in TCA cycle are converted into amino acids by transamination. FAT is oxidized to form acetyl CoA which enters the citric acid cycle. MALATE of citric acid cycle pass thru mitochondrial membrane into CYTOSOL converted to glucose by gluconeogenesis. Prepared by: Mr. Norman 9/16/2018

INTER-RELATIONSHIP IN THE METABOLISM OF PROTEINS, LIPIDS & CARBOHYDRATES FATTY ACIDS with odd number of carbon atoms also enters citric acid cycle PROPIONATE PROTEIN is hydrolyzed to AMINO ACIDS. Prepared by: Mr. Norman 9/16/2018

Any Question??? Thank You! Prepared by: Mr. Norman 9/16/2018