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Respiration and Fermentation Lab on-line #10
Objectives:
Monitor respiration activity in yeast by observing CO2 production as sugar is metabolized
Investigate the effects of temperature on yeast fermentation
Respiration
Living cells use ATP (adenosine triphosphate) as their energy "currency". The energy released when a molecule of ATP is hydrolyzed (ATP ADP + PO4) is used to drive cellular reactions. To stay alive, a cell must continually regenerate its supply of ATP (from ADP & inorganic phosphate). A working muscle cell recycles its ATP at a rate of ~10 million molecules per second! Cells harvest potential energy from metabolic fuels such as glucose by catabolizing them and using the energy to synthesize ATP. This process of harvesting chemical energy is called respiration.
Different organisms use different catabolic processes to harvest chemical energy. Most eukaryotic cells use cellular respiration, the most efficient catabolic pathway for energy harvest. Cell respiration is also called aerobic respiration, because oxygen is consumed as a reactant along with an organic fuel:
C6H12O6 + 6 O2 6 CO2 + 6 H2O + ENERGY.
Most of the reactions of cell respiration, during which a molecule of fuel is degraded completely, take place in the mitochondria. During aerobic respiration, a reduced fuel molecule is oxidized as high-energy electrons are stripped away from the fuel by the coenzymes NAD+ & FAD. The electrons are then donated to an electron transport chain in the mitochondria, where their energy is used to drive ATP synthesis. Aerobic respiration allows cells to harvest a large proportion of the potential energy contained in organic fuels (~40-50% of the potential energy in glucose).
Fermentation
Fermentation is a simpler process that results in a partial degradation of an organic fuel. Fermentation does not require the presence of any specialized organelles and does not require oxygen as a reactant, so it can
Objectives:
Monitor respiration activity in yeast by observing CO2 production as sugar is metabolized
Investigate the effects of temperature on yeast fermentation
Respiration
Living cells use ATP (adenosine triphosphate) as their energy "currency". The energy released when a molecule of ATP is hydrolyzed (ATP ADP + PO4) is used to drive cellular reactions. To stay alive, a cell must continually regenerate its supply of ATP (from ADP & inorganic phosphate). A working muscle cell recycles its ATP at a rate of ~10 million molecules per second! Cells harvest potential energy from metabolic fuels such as glucose by catabolizing them and using the energy to synthesize ATP. This process of harvesting chemical energy is called respiration.
Different organisms use different catabolic processes to harvest chemical energy. Most eukaryotic cells use cellular respiration, the most efficient catabolic pathway for energy harvest. Cell respiration is also called aerobic respiration, because oxygen is consumed as a reactant along with an organic fuel:
C6H12O6 + 6 O2 6 CO2 + 6 H2O + ENERGY.
Most of the reactions of cell respiration, during which a molecule of fuel is degraded completely, take place in the mitochondria. During aerobic respiration, a reduced fuel molecule is oxidized as high-energy electrons are stripped away from the fuel by the coenzymes NAD+ & FAD. The electrons are then donated to an electron transport chain in the mitochondria, where their energy is used to drive ATP synthesis. Aerobic respiration allows cells to harvest a large proportion of the potential energy contained in organic fuels (~40-50% of the potential energy in glucose).
Fermentation
Fermentation is a simpler process that results in a partial degradation of an organic fuel. Fermentation does not require the presence of any specialized organelles and does not require oxygen as a reactant, so it can