BackCellular Respiration and Energy Transformation in Biology
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Terms in this set (20)
Photosynthesis in chloroplasts converts CO2 and H2O into organic molecules using light energy. Cellular respiration in mitochondria breaks down these molecules to produce ATP, powering cellular work and releasing heat.
Glycolysis breaks down glucose into 2 pyruvate molecules, producing a net gain of 2 ATP and 2 NADH molecules in the cytoplasm.
Pyruvate can enter aerobic cellular respiration by converting to Acetyl CoA in mitochondria or undergo fermentation to produce ethanol, lactate, or other products if no oxygen is present.
Pyruvate is converted to Acetyl CoA, releasing CO2 and producing NADH. This occurs in the mitochondrial matrix and is necessary for entry into the Citric Acid Cycle.
Acetyl CoA enters the Citric Acid Cycle; it is produced by the oxidation of pyruvate.
It oxidizes Acetyl CoA to CO2, generating NADH, FADH2, and GTP (energy equivalent to ATP) for use in oxidative phosphorylation.
They act as electron carriers, donating electrons to the electron transport chain to drive ATP production.
The ETC consists of Complexes I, III, IV, cytochromes, and cofactors like heme groups. Electrons from NADH and FADH2 pass through these complexes, pumping protons to create a gradient.
Oxygen acts as the final electron acceptor at Complex IV, combining with electrons and protons to form water.
Protons flow back across the mitochondrial membrane through ATP synthase, driving the phosphorylation of ADP to ATP.
ATP synthase catalyzes the formation of ATP from ADP and inorganic phosphate using the proton gradient.
ATP production would stop because the proton gradient energy would not be harnessed to drive ATP synthesis.
Substrate-level phosphorylation directly forms ATP during glycolysis and the Citric Acid Cycle; oxidative phosphorylation produces ATP using the proton gradient in the ETC.
Fermentation regenerates NAD+ from NADH in the absence of oxygen, allowing glycolysis to continue producing ATP anaerobically.
Yeast produce ethanol and CO2; humans produce lactate.
NAD+ is required to accept electrons during glycolysis; without regeneration, glycolysis and ATP production would halt.
Fats and proteins are broken down into molecules that enter cellular respiration pathways at various points, such as Acetyl CoA or intermediates of the Citric Acid Cycle.
Proton gradient is dissipated without ATP production, causing heat generation, low ATP levels, and metabolic acidosis.
Oxygen is the final electron acceptor in the ETC, allowing continuous electron flow and maximal ATP synthesis.
Approximately 30-32 ATP: 2 from glycolysis, 2 from the Citric Acid Cycle, and about 26-28 from oxidative phosphorylation.