Anatomy and Physiology Biology 2402 Chapter-25 Metabolism and Energetics

Anabolic and Catabolic Reactions http://web. biosci. utexas

Figure 25-2 Nutrient Use in Cellular Metabolism Structural, functional, and storage components Triglycerides Glycogen Proteins Organic compounds that can be absorbed by cells are distributed to cells throughout the body by the bloodstream. Nutrient pool Fatty acids Glucose Amino acids Three-carbon chains Two-carbon chains MITOCHONDRIA Citric acid cycle Electron transport system Coenzymes KEY  Catabolic pathway  Anabolic pathway 3

http://www. sumanasinc http://www.sumanasinc.com/webcontent/animations/content/cellularrespiration.html http://www.mhhe.com/biosci/bio_animations/MH01_CellularRespiration_Web/

Glycolysis http://highered.mheducation.com/sites/0072507470/student_view0/chapter25/animation__how_glycolysis_works.html http://sites.sinauer.com/cooper6e/animation0303.html

Transition reaction

Kreb’s cycle/Citric Acid Cycle http://sites.sinauer.com/cooper6e/animation0304.html Kreb’s cycle/Citric Acid Cycle http://highered.mheducation.com/sites/0072507470/student_view0/chapter25/animation__how_the_krebs_cycle_works__quiz_1_.html

Electron transport system chemiosmosis (part 1) http://highered.mheducation.com/sites/0072507470/student_view0/chapter25/animation__electron_transport_system_and_atp_synthesis__quiz_1_.html

Electron transport system chemiosmosis (part 2) http://web.biosci.utexas.edu/psaxena/MicrobiologyAnimations/Animations/ElectronTransport/PLAY_etc.html

Oxygen debt and lactic acid http://www.yteach.co.uk/page.php/resources/view_all?id=respiration_oxygen_debt_cell_respiration_aerobic_respiration_anaerobic_respiration_glucose_energy_protein_fat_water_oxygen_carbon_dioxide_t_page_16&from=search

http://www.wiley.com/college/test/0471787159/biology_basics/animations/glycolysisAndFermentation.swf Fermentation

Alcoholic fermentation http://people.cst.cmich.edu/schul1te/animations/fermentation.swf Alcoholic fermentation

Glycogenesis & Glycogenolysis https://youtu.be/1R6KB12Wtyw Glycogenesis is the synthesis of glycogen from glucose in the liver and skeletal muscle. It is regulated by insulin, and occurs when the blood glucose levels are high. Insulin stimulate liver and mucle cells to absorb glucose and store it as glycogen. Glycogenolysis is the break down of glycogen to release glucose. It is regulated by glucagon and epinephrine, and occurs in response to low glucose blood levels. Liver and muscle cells are stimulated by these two hormones to break down glycogen to release glucose. Only liver cells are able to release glucose to the blood.

Gluconeogenesis http://www.wiley.com/college/boyer/0470003790/animations/gluconeogenesis/gluconeogenesis.htm Gluconeogenesis is the generation of glucose from non carbohydrate molecules like pyruvic acid, lactic acid, glycerol, and glucogenic amino acids. It is stimulated by cortisol and glucagon and occurs primarily in the liver. It can also occur in the kidney.

Lipid catabolism

Lipolysis and Other Lipids Functions Adipose triglycerides are broken down and released as free fatty acids. Free fatty acids are taken up by cells and broken down by beta-oxidation into acetylCoA which can enter the citric acid cycle or can be converted to ketone bodies. Other lipids are used as structural molecules or to synthesize essential molecules. Examples include phospholipids of plasma membranes lipoproteins that transport cholesterol thromboplastin for blood clotting myelin sheaths to speed up nerve conduction cholesterol used to synthesize bile salts and steroid hormones.

Health problems Hypertrophic obesity – severe increase in adipose cell size via massive accumulation of fatty acids within the fat droplet. These mainly occur in White adipose tissue Hypercellular obesity – result from the over-abundance of adipocytes. This is due to the adipose cells abnormally divided in fetal, neonatal period. Adipose cells do not divide in adults therefore the division took place in youth.

Amino Acids Catabolism Amino acids must be converted to various substances to enter the Krebs cycle for oxidation. Amino acid conversion occurs in the liver. Amino acids can be: Deaminated Decarboxylated Dehydrogenated Deamination removes the amino group and creates nitrogenous wastes such as urea. http://www.wiley.com/college/grosvenor/0470197587/animations/Animation_Protein_Metabolism/Energy/media/content/met/anima/met3a/frameset.htm

Essential Amino Acids Essential amino acids are molecules that we cannot synthesize, or that we synthesize in low amount. Humans cannot synthesize leucine, isoleucine, lysine,methionine, phenylalanine, threonine, tryptophan, and valine. Arginine and histidine are not synthesized in sufficient amounts.

Metabolic Pathways during the Absorptive State

Metabolic Pathways during the Postabsorptive State

Fasting and Starvation Fasting means going without food for many hours or a few days. Starvation implies weeks or months of food deprivation or inadequate food intake. Catabolism of stored triglycerides and structural proteins can provide energy for several weeks. The amount of adipose tissue determines the lifespan possible without food. During fasting and starvation, nervous tissue and red blood cells continue to use glucose for ATP production.