Transcript Slide 1
Metabolism The sum total of all anabolic and all catabolic reactions occurring in an organism. What factors affect your metabolic rate? Basal Metabolic Rate = minimal caloric requirement needed to sustain the life in a resting individual Age, Gender, Caffeine, Nicotine ,Exercise Height ,Pregnancy, Breast Feeding Food Intake, Starving, Malnutrition ,Couch Potato muscle, liver, brain, kidney have high energy needs High fever, High Stress, Environmental Temperature Change Thyroid Function, Oxygen Consumption, Mitochondrial Function Body Mass, Gene Expression—insulin/glucagon Heat Production = Thermogenics Chemical reactions in most organisms take place within a narrow range of temperatures. These narrow ranges of temperatures are not high enough to supply the energy need to get the reaction started… Lower energy needed to start reactions (catalysts) Speed up chemical reactions Reusable—not used up in reactions Work on specific substrates (depends on the enzymes active site) Affected by temperature, pH, concentrations… Hydrogen Peroxide Catalase or Peroxidase 2H2O2 2H2O + O2 Enzyme-Substrate Complex H 2O O2 2H202 H 2O Active Site Catalase Catalase Catalase Substrate breaks down Enzyme is recycled. Enzyme changes shape to fit and hold the substrate Hydrogen Peroxide joins With the enzyme catalase Most biological enzymes are proteins. Not all proteins are enzymes, but most enzymes are proteins. They perform the chemical reactions in cells. A catalyst is a molecule which increases the rate of a reaction. A substrate is a molecule upon which an enzyme acts to yield a product. Enz A ------> B Here’s one example, b-galactosidase catalyzes the following reaction b-galactosidase lactose -----------------------> glucose + galactose A biosynthetic pathway is made up of a series of enzymes which take a molecule and convert it into another molecule through a sequence of catalyzed reactions. For example, shown below is a hypothetical pathway composed of four enzymes, labeled 1 through 4. These enzymes convert the molecule A into the molecule E through a series of intermediates (B, C, and D): 1 2 3 4 A --------> B -------> C -------> D -------> E These pathways are necessary to make the major molecules in cells: nucleotides, amino acids, sugars, and lipids. Thyroid Gland and Metabolism Fat and Mitochondria Glucose Metabolism Diet and Metabolism Exercise and Metabolism Metabolism is the sum total of all interactions between molecules within cell environments. The chemistry of life is organized into metabolic pathways. Metabolic pathways begin with a specific molecule, which is then altered in a series of defined steps to form a specific product. A specific enzyme catalyzes each step of the pathway. A cell’s physical and chemical environment affects enzyme activity. The activity of an enzyme is affected by general environmental conditions, such as temperature and pH. Each enzyme works best at certain optimal conditions, which favor the most active conformation for the enzyme molecule. Sarin is the nerve gas that was released by terrorists in the Tokyo subway in 1995. Sarin binds covalently to the R group on the amino acid serine. Serine is found in the active site of acetylcholinesterase, an important nervous system enzyme.