Chapter 5 Metabolism

Metabolism – all the chemical reactions Catabolism – larger molecules are broken down to smaller molecules. Glucose – CO2 and water – cellular respiration – energy is released Anabolism – larger molecules are synthesized from smaller molecules. CO2 + water – glucose –photosynthesis Energy is used Energy released in catabolic reactions is stored in ATP

ATP – quick source of energy in cells Energy carrier molecule Synthesis, movement, transport ATP ----- ADP + Phosphate + energy ADP + phosphate + energy ---- ATP

Almost all the chemical reactions – enzymes Biological catalysts Speed up chemical reactions Come out of the reaction unchanged Absence enzymes – chemical reactions take place slow – cells cannot survive Specific for its substrate Substrate – substance with which the enzyme reacts.

Bring molecules together Weaken bonds in a molecule – breaks down

denaturation Enzymes are saturated No free enzymes to interact With the excess substrate.

Enzyme inhibitors – competitive, noncompetitive Compete with the substrate for the active site. Sulfanilamide – synthetic drug – UTI Para aminobenzoic acid (PABA) ------ folic acid Enzyme Drug takes the place of PABA on the enzyme Inactivates the enzyme

Noncompetitive inhibitor binds to the allosteric site on the enzyme Allosteric site – site other than the active site Shape of the active site is changed Enzyme is inactivated Cyanide

Cellular respiration Glucose is catabolized Oxidation reduction reactions Loss of electron or hydrogen atom –oxidation Gain of electron or hydrogen atom – reduction Leo says ger

Oxidation reduction reactions are coupled They take place simultaneously

Catabolism of glucose – energy (ATP) Cellular respiration Aerobic respiration Anaerobic respiration Aerobic respiration – O2 is used 6C6H12O6 +6O2 > 6CO2 + 6H2O + energy Glucose – oxidized – CO2 O2 reduced to water Glycolysis, transition reaction Krebs cycle, oxidative phosphorylation (electron transport chain)

Glycolysis Sugar splitting Cytosol = liquid Part of the cytoplasm Each molec. Glucose 2 pyruvic acid + 2NADH + 4ATP Cell gains only 2 ATP Substrate level phosphorylation Phosphate is added from a substrate to ADP

Transition reaction Decarboxylated oxidized matrix of mitochondria each molecule of glucose 2 acetyl CoA + 2NADH + 2 CO2 6NADH + 2 FADH2 + 4CO2 + 2 ATP interact with the electron transport chain located on the inner membrane of mitochondria electron transport chain – inner membrane of mitochondria

Power house – cellular respiration DNA 70S ribosomes intermembrane space

oxidized flavin mononucleotide FMN chemiosmosis ubiquinone Q oxidation of ETC cytochrome cyt phosphorylation of ADP

summary NADH – 3ATP 10 NADH – 30 ATP FADH2 – 2 ATP 2 FADH2 – 4 ATP

Anaerobic respiration Similar to aerobic respiration Final e- acceptor is an inorganic substance other than O2 Pseudomonas aeruginosa uses nitrate ion as the final e- acceptor

Fermentation O2 is not used Only glycolysis takes place 2ATP are made Organic molecule is the final e- acceptor

Lipids, proteins – used for energy Triglyceride  glycerol + 3 fatty acids Exoenzyme - lipase Glycerol – dihydroxyacetone phosphate Goes into glycolysis Fatty acid  many units of acetyl CoA Goes into Krebs cycle Proteins – amino acids – proteases AA – intermediates of glycolysis, Krebs cycle

Photosynthesis Plants and algae – chloroplasts 6CO2 + 6 H2O  C6H12O6 +6O2 Light dependent reactions Light independent reactions ( Calvin-Benson reaction)

Flow of energy sunlight CO2 + water ---------- glucose ATP --- energy Synthesis, transport, movement Sun is the ultimate source of energy