Cell Respiration Flashcards
What is cellular respiration?
Cellular respiration is the process by which cells break down glucose (or other nutrients) in the presence of oxygen to produce ATP (adenosine triphosphate), which is used for energy. The process also produces carbon dioxide and water as byproducts.
What is the overall equation for cellular respiration?
C6H12O6+6O2→6CO2+6H2O+ATP
What are the three main stages of cellular respiration?
Glycolysis
Krebs Cycle (Citric Acid Cycle)
Electron Transport Chain (ETC)
Where does glycolysis take place?
Glycolysis occurs in the cytoplasm of the cell, outside of the mitochondria.
Where do the Krebs cycle and electron transport chain take place?
Both the Krebs cycle and the electron transport chain take place in the mitochondria. The Krebs cycle occurs in the matrix, while the electron transport chain occurs in the inner mitochondrial membrane.
What is the purpose of glycolysis?
Glycolysis breaks down glucose (6 carbons) into two molecules of pyruvate (3 carbons each) while producing a small amount of ATP and NADH. It does not require oxygen (anaerobic process).
What are the products of glycolysis?
2 pyruvate molecules
2 ATP (net gain)
2 NADH molecules
2 molecules of water (H₂O)
Is glycolysis an anaerobic or aerobic process?
Glycolysis is an anaerobic process, meaning it does not require oxygen.
What does anaerobic mean?
does not require oxygen
What happens in the Krebs Cycle?
The Krebs Cycle further breaks down pyruvate into carbon dioxide, producing high-energy molecules such as NADH, FADH₂, and ATP in the process. It also regenerates oxaloacetate for the cycle to continue.
What are the products of one round of the Krebs Cycle?
3 NADH
1 FADH₂
2 CO₂ (carbon dioxide)
1 ATP (per pyruvate)
How many rounds of the Krebs Cycle occur per molecule of glucose?
Since one molecule of glucose is broken down into two molecules of pyruvate, there are two rounds of the Krebs Cycle per molecule of glucose.
What is the Electron Transport Chain (ETC)?
The ETC is a series of protein complexes located in the inner mitochondrial membrane. It uses the high-energy electrons from NADH and FADH₂ to create a proton gradient that drives the production of ATP via ATP synthase.
What is the role of oxygen in the Electron Transport Chain?
Oxygen acts as the final electron acceptor in the ETC. It combines with electrons and protons (hydrogen ions) to form water. Without oxygen, the ETC would stop, and ATP production would cease.
What is produced by the Electron Transport Chain?
Water (H₂O)
ATP (via ATP synthase)
NAD+ and FAD (recycled for use in the Krebs cycle)
How many ATP molecules are produced in cellular respiration?
In total, approximately 36-38 ATP molecules are produced from one molecule of glucose during cellular respiration, depending on the efficiency of the system.
How is ATP generated in the Electron Transport Chain?
ATP is generated in the ETC via chemiosmosis, where a proton gradient drives the ATP synthase enzyme to convert ADP and inorganic phosphate (Pi) into ATP.
What are the two types of fermentation?
Lactic acid fermentation
Alcohol fermentation
What is Alcohol fermentation?
Occurs in yeast and bacteria, produces ethanol, carbon dioxide, and ATP.
What is Lactic Acid Fermentation?
Occurs in muscle cells (when oxygen is scarce), producing lactic acid and ATP.
Why is oxygen essential for efficient ATP production in cellular respiration?
Oxygen is required for the electron transport chain to function, which is the main process for ATP production. Without oxygen, cells must rely on anaerobic processes like fermentation, which produce much less ATP.
What happens if cellular respiration is disrupted or inhibited?
If cellular respiration is disrupted, cells cannot produce sufficient ATP, which may lead to cellular dysfunction or death. For example, in the absence of oxygen, fermentation may occur, but only small amounts of ATP are generated.
How does cellular respiration relate to photosynthesis?
Cellular respiration and photosynthesis are complementary processes:
Photosynthesis converts light energy into glucose, which is used by cells as a fuel source.
Cellular respiration breaks down glucose to produce ATP, which is used for cellular activities.
