Metabolism • General concept of metabolism + Bioenergetics • Cellular respiration (glykolysis + CKC + oxidative phosphorylation) • Sacharide metabolism + photosynthesis • Lipid metabolism • Metabolism of nitrous compounds Obecné znaky metabolismu + bioenergetika BUNĚČNÁ TEORIE Robert Hook (1667) "buňka" 1. Buňky tvoří veškerou živou hmotu (x viry). 2. Veškeré buňky pocházejí z jiných buněk (x samoplození). 3. Informace se předávají z generace na generaci. 4. V buňkách látky podléhají chemickým přeměnám. 5. Buňky reagují na vnější podněty. Otevřené systémy: tok látek, energie a informací dovnitř a ven dynamická rovnováha → ustálený stav Pravá rovnováha → smrt organismu Metabolic types (trofika, trofé = výživa): Energy source: light→ phototroph chemical reaction(redox) → chemotrophs Proton/electron donor acceptor Anorganic Organic Oxygen Other lithotrophs organotrophs aerobic anaerobic (líthos = stone) Fermentace: „disproporcionace“ Např.: C6H12O6 2 CH3-CH(OH)-COOH C6H12O6 2 CH3-CH2-OH + 2CO2 To be continued…….. Carbon source: anorganic → autotrophs organic → heterotrophs Common metabolic types METABOLISM Carbon source Proton source Proton example acceptor photolithotrophs CO2 H2O CO2 Green parts of (autotrophic) plant photolithotrophs Organic comp H2O (CO2) Some (heterotrophic) photosynthetic bacteria Photoorganotrophs Organic comp. Organic comp CO2 Some algae nad (heterotrophic) bacteria chemoorganotrophs Organic comp Organic comp O2 Animals, aerobic aerobic MO 2- Chemoorganotrophs Organic comp Organic comp SO4 Soil anaerobic - Anaerobic respiration NO3 bacteria - HCO3 Chemoorganotrophs Organic comp Organic comp ---- yeasts fermenting chemolithotrophs CO2 H2S, CH4, NH3, O2 sulphur bacteria, H2 nitrifying Metabolism katabolism anabolism Gain of energy Consumption of energy Interconected and coordinated + amfibolic and anaplerotic pathways Basic concept of metabolism and bioenergetics autorophs heterotrophs Main metabolic pathways http://expasy.org/tools/pathways/ Overview of catabolism chemoorganotrophic aerobic FATS POLYSACCHARIDES PROTEINS Stage 1 fatty acids, glucose, amino acids glycerol other sugars Stage 2 acetyl CoA H2O O2 CoA Stage 3 – v oxidative e Krebs cycle v phosphorylation CO2 ATP ADP + Pi 14 Anabolismus production phase of metabolism – biosynthesis Increasing complexity of products requires energy - ATP Reductive character – requires reducing agent - NADPH + H+ 1. stage: intermediates of 2. a 3. phase of catabolism (CKC) precursors 2. stage: biosynthesis of bulding blocs - monomers 3. stage: biosynthesis of polymers from activated monomers Summary Anabolic Catabolic • Divergent process • Convergent process • Reductive • Oxidative • End products are complex • End products are simple molecules molecules • Requires Energy • Releases Energy • Builds something • Breaks something down Localized in different compartmets Common : intermediates, some enzymatic reactions, starting and end products Metabolic pathway series of chemical reactions occurring within a cell Metabolic pathway involves the step-by-step modification of an initial molecule to form another product course of metabolic pathways: linear, branched, cyclic, spiral ATP = common currency ? ATP = společná měna 1. Electrostatic repulsion Enzyme 2. Resonance “handle” stabilization O- HO P O- O Bioenergetics Gibbs free energy -most useful termodynamic quantity for biological systems - measures the "useful" or process-initiating work obtainable from a reaction at a constant temperature and pressure G = H - TS Free energy is a measure of how far a reaction. is from equilibrium G r x n = Gp r o d u c t s - Gs u b s t r a t e s A + B P G rxn G A + B P rxn A + B P Free Energy G > 0 G < 0 G = 0 endergonic exergonic equilibrium How is ∆G related to ∆Go? The concentration dependence of G for a chemical reaction is: Ratio of products to reactants under the reaction conditions { o [products] ∆G = ∆G + R Tln ( [substrates] ) Gas constant Temperature (8.31 J/ Ko-mol) (in K)o o Under standard conditions:∆ G = ∆ G In bichemistry: G’o = free energy released for a reaction: • Under Standard Conditions – 1M reactants and products – 25oC – Ph 7.0 • Where Concentration Terms are Ignored for: – water – Protons G´ = G0´ + RT ln [produkty]/[reaktanty] Direction of the given reaction depends on the concentration of reactants and products Example: DAP GA3P G (kJ mol-1) (M) (M) 1,0 1,0 + 7,7 (G0) 2,0 x 10-1 9,0 x 10-3 0 (G) 1,0 x 10-1 1,0 x 10-4 - 9,5 (G) 1,0 x 10-4 1,0 x 10-1 + 24,8 (G) To be continued……… Exergonic reactions: G < 0 Endergonic reactions: G > 0 - Proceeds spontaneously does not proceed sponatneously - does not require energy - catabolism generally – don’t exist But : ligases active transport anabolism (celkově) ? Solution: coupling of reactions Glucose + Pi ↔ glucose phosphate + H2O ΔGº’ = +13.8 kJ/mol Glucose + Pi ↔ glucose 6-phosphate + H2O ΔGº’ = +13.8 kJ/mol ATP + H2O ↔ ADP + Pi ΔGº’ = -30.5 kJ/mol Glucose+ ATP ↔ glucose 6-phosphate+ ADP ΔGº’ = -16.7 kJ/mol Synthesis of ATP in organisms Substrate phosphorylation S-P + ADP S + ATP (transferase) G°’ADP = -30,5 kJ/mol S1-S2 + ADP + Pi S1 + S2 + ATP (+ H2O) (ligase) …. ATP synthesis in organisms Membrane phosphorylations: ADP + Pi ATP + H2O (hydrolases) ● oxidative phosphorylation ( in mitochondria) ● Photophosphorylation (chloroplasts) Usage of ATP • chemical work: transferases and ligases • Osmotic work – active transport of compounds (against concentration gradient) • Mechanical work: actomyosin complex (muscle contraction), flagela, cytoskeleton • Regulatory work – signal transduction Membrane transport Biological membranes are semi-permeable, very limited number of molecules can cross the membrane by plain diffusion Pasive transport Mobil trnasporter -valinomycin Chanel transporter- gramicidin Protein transporters Transport of compounds through permanent pores - porins Molecular sieve Gap junction Aperture like function Pasive vs active transport © Espero Publishing, s.r.o. Active tra nsport deltaGtransport= -RT ln Cvně/C uvnitř .