Review 3 Metabolism Respiration Photosynthesis AP Biology Respiration

Review 3: Metabolism. Respiration & Photosynthesis AP Biology

Respiration & Photosynthesis a. Energy production through chemiosmosis b. Coupled reactions get the work done c. Respiration d. Photosynthesis e. Regulation of metabolism is through negative feedback of enzyme pathways

Energy Production through Chemiosmosis a. Chemiosmosis -Coupling of the proton pump to ATP synthesis -Responsible for almost all of the ATP produced from food & all of the ATP produced from photosynthesis

Chemiosmosis a. Pumping of H+ ions onto one side of a membrane through protein pumps in an Electron Transport Chain (ETC) b. Flow of H+ ions across a membrane down the concentration gradient through ATP synthase

Coupled Reactions Get the Work Done a. Oxidation & Reduction b. ETC & pumping of H+ (protons)

Oxidation & Reduction a. Oxidation – loss of an electron b. Reduction – gain of an electron c. ALWAYS TAKE PLACE TOGETHER!!!

Respiration a. Mitochondria b. Anaerobic: glycolysis, fermentation

Mitochondria a. ETC in inner membrane: Cristae increase surface area b. H+ ions concentrated in intermembrane space & flows into matrix through ATP synthase c. Oxidative phosphorylation: O 2 final electron acceptor + NAH/FADH to donate electron d. Kreb’s cycle produces electron carriers: NADH, FADH e. High ATP production (~36 ATP)

ATP Synthase a. General term for an enzyme that can synthesize ATP from ADP and inorganic phosphate by using energy b. ADP + Pi → ATP

Oxidative Phosphorylation a. Metabolic pathway that uses energy released by oxidation of nutrients to produce ATP

Kreb’s Cycle a. Occurs in matrix of mitochondrion b. Generates 2 ATP per molecule of glucose c. Produces electron carriers: NADH, FADH

Anaerobic Respiration a. Inorganic molecule other than oxygen accepts the hydrogen b. Low ATP production (~2 ATP) c. Glycolysis -Converts glucose into pyruvate -Free energy released is used to form ATP & NADH -In the absence of oxygen, cells must rely on glycolysis to produce ATP. • Fermentation -Organic molecule accepts the hydrogen atom generated by glycolysis

Photosynthesis a. Chloroplasts b. Calvin cycle c. C 4 & CAM plants

Chloroplasts a. H+ ion concentration in inner thylakoid space & flows out into stroma b. Phosphorylation: light energy + splitting of water to donate electron c. Light dependent reactions: Photosystem II (produces ATP) & Photosystem I (produces NADPH)

Light Dependent Reactions a. Photosystem II: 1 st protein complex, In thylakoid membrane, produces ATP b. Photosystem I: produces NADPH

Calvin Cycle a. 3 rd stage of photosynthesis b. Formation of organic molecules from atmospheric CO 2 c. May occur in absence of light as long as ATP & NADPH are available d. Light independent reaction e. Carbon fixation through Ru. Bis. Co enzyme f. Use ATP & NADPH from light reactions to produce 3 C sugars

C 4 & CAM Plants a. Adaptation in hot, dry ecosystems because stomates close a lot b. Reduce photorespiration: Low carbon fixation in a high oxygen/low CO 2 • Regulation of metabolism is through negative feedback of enzyme pathways.