Overview of cellular respiration | Cellular respiration | Biology | Khan Academy
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Cellular respiration is a complex process starting with glucose undergoing glycolysis to form pyruvate, leading to either fermentation or acetyl-CoA formation. The process continues in the citric acid cycle, producing NADH and ATP equivalents, ultimately contributing to ATP production through oxidative phosphorylation.
Insights
- Glycolysis is the initial step of cellular respiration, yielding 2 ATP and 2 NADH; pyruvate generated can undergo fermentation without oxygen.
- Cellular respiration culminates in the citric acid cycle, occurring in the mitochondria matrix, producing NADH, CO2, and ATP, with oxidative phosphorylation leveraging NADH and QH2 for ATP synthesis.
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Recent questions
What is cellular respiration?
Cellular respiration is a complex process that occurs inside cells to convert glucose into ATP, the energy currency of the cell.
What is glycolysis?
Glycolysis is the initial stage of cellular respiration where glucose is broken down in the cytosol to form pyruvate, producing 2 net ATP and 2 NADH molecules.
What happens in the citric acid cycle?
The citric acid cycle, also known as the Krebs cycle, involves the conversion of acetyl-CoA to citric acid in the mitochondria matrix, producing NADH, CO2, and ATP equivalents.
How is ATP produced in cellular respiration?
ATP is produced in cellular respiration through oxidative phosphorylation, where NADH and QH2 from the citric acid cycle contribute to creating a proton gradient for ATP synthesis.
Where does the citric acid cycle take place?
The citric acid cycle occurs in the matrix of the mitochondria, while the conversion of coenzymes in the electron transport chain happens across the membrane of the cristae, the inner membrane folds of the mitochondria.
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Summary
00:00
Cellular Respiration: Energy Production in Cells
- Overview of cellular respiration, a complex process inside cells.
- Glucose is the starting point, undergoing glycolysis in the cytosol to form pyruvate.
- Glycolysis produces 2 net ATP and 2 NADH molecules through reduction.
- Pyruvate can lead to fermentation if no oxygen is present, converting NADH back to NAD.
- Transition to aerobic respiration involves pyruvate converting to acetyl-CoA.
- Acetyl-CoA transfers acetyl group to oxaloacetic acid, forming citric acid in the citric acid cycle.
- Citric acid cycle involves multiple steps, producing NADH, CO2, and ATP equivalents.
- NADH and QH2 from the cycle are later oxidized in oxidative phosphorylation.
- NADH and QH2 contribute to creating a proton gradient for ATP production.
- Total ATP production from cellular respiration ranges from 27 to 38 ATP, with observed efficiency around 29 to 30 ATP.
12:24
Mitochondrial Processes: Citric Acid Cycle and Electron Transport
- The citric acid cycle takes place in the matrix of the mitochondria, while the conversion of coenzymes in the electron transport chain occurs across the membrane of the cristae, which are inner membrane folds of the mitochondria.
