Physiology 12. Metabolism. Metabolism. Cellular metabolism. The synthesis and Breakdown of organic molecules required for cell structure and function

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1 Physiology 12 Cellular metabolism Germann Ch3 Metabolism The synthesis and Breakdown of organic molecules required for cell structure and function Metabolism Anabolism = Synthesis Catabolism = Breaking Apart

2 Chemical Reactions A + B C + D The rate of any chemical reaction is influenced by: Concentration of substrates and products Temperature Activation Energy Catalyst Enzymes Catalyze the majority of chemical reactions inside the cell and body

3 Enzymes Are not changed by the reactions they catalyze enzyme + Substrate enzyme-substrate complex Product + enzyme Enzymes Are not changed by the reactions they catalyze Have binding dynamics similar to receptors

4 Binding Site Characteristics (enzyme or receptor) Specificity Affinity Saturation Competition Modulation, allosteric,, or covalent

5 Enzymes Are not changed by the reactions they catalyze Have binding dynamics similar to receptors Change only the rate of reactions Enzymes Are not changed by the reactions they catalyze Have binding dynamics similar to receptors Change only the rate of reactions (not products) Lower the activation energy required for a reaction to proceed Activation Energy

6 Some enzymes employ cofactors NAD + (nicotinamide adenine dinuclotide) FADH 2 (Flavine adnine dinuclotide) Many reactions in the body are part of larger metabolic pathways A B C D E

7 Many reactions in the body are part of larger metabolic pathways A B C D E Pathways can also branch Enzymes can regulate metabolic pathways Enzyme concentration can determine reaction rate.

8 Enzymes can regulate metabolic pathways Enzyme concentration can determine reaction rate. Enzymes activity can be alosterically and covalently modulated

9 Enzymes can regulate metabolic pathways Enzyme concentration can determine reaction rate. Enzymes activity can be alosterically and covalently modulated Enzymes can change available substrate concentrations.

10 Enzymes can regulate metabolic pathways Enzyme concentration can determine reaction rate. Enzymes activity can be alosterically and covalently modulated Enzymes can change available substrate concentrations. (example of branched pathway) Enzymes can regulate metabolic pathways Enzyme concentration can determine reaction rate. Enzymes activity can be alosterically and covalently modulated Enzymes can change available substrate concentrations. Product inhibition

11 Who provides energy to the cell Who provides energy to the cell Carbohydrates Lipids Proteins What form does the cell get its energy in? ATP

12 Metabolic Pathways There are three main enzymatic pathways that convert food into cellular energy. Metabolic Pathways Glycolysis Krebs Cycle Oxidative Phosphorylation

13 Glycolysis Aka: : Sugar cutting

14 Glycolysis Does not require oxygen (anerobic( anerobic) Happens in the cytosol Produces 2 ATP for each glucose Uses 2NADH as Coenzymes End product is pyruvate Hold your Breath!!! What if there is no oxygen around?

15 The Krebs Cycle Aka: : the citric acid cycle, the tricarboxylic acid cycle

16 The Krebs Cycle Requires Oxygen (not as a reactant, but the wheel wont turn without it) Takes place in the inner compartment of the mitochondria Produces 1 GTP (=1ATP) Produces 3 NADH and 2 FADH So far our one sugar molecule has given us: 2ATP from glycolysis 2NADH from glycolysis 1ATP from Krebs 3 NADH and 2 FADH Total 3ATP, 5NADH and 2FADH Was it really worth it Where s the payoff??

17 Oxidative Phosphorylation Aka: : the electron transport chain

18 Oxidative Phosphorylation Requires and uses oxygen in reactions Uses a complex of membrane bound enzymes (cytochromes)) that pass electrons Is bound to the inner mitochondrial membrane Uses hydrogen pumping to produce ATP Makes 3 ATP from each NADH Makes 2 ATP from each FADH One Glucose molecule Lets add it up!!

19 What about fat? Stored in adipocytes Feeds into the Krebs cycle and oxidative Phosphorylation pathways Undergoes Beta Oxidation pathway first.

21 Proteins Goes through Oxidative Deamination pathways Feed into Krebs Cycle and Oxidative Phosphoralation Pathways Ammonia is removed as Urine.

22 Essential Nutrients Must be essential for health can not be synthesized by the body Essential Nutrients 9 of the 20 amino acids Lineolic and Lineoleic acids Inositol Choline Carnitine Vitamins

23 END

Energy Production In A Cell (Chapter 25 Metabolism)

Energy Production In A Cell (Chapter 25 Metabolism) Large food molecules contain a lot of potential energy in the form of chemical bonds but it requires a lot of work to liberate the energy. Cells need