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These flashcards cover key concepts, processes, and terms related to cellular respiration, including glycolysis, the Krebs Cycle, and oxidative phosphorylation.
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What is cellular respiration?
The process by which cells extract energy from food and convert it into ATP.
What is ATP?
Adenosine Triphosphate, the energy currency of the cell.
What does the law of conservation of energy state?
Energy cannot be created or destroyed.
What are the three main parts of ATP?
Three phosphate groups, ribose, and adenine.
What happens when ATP is broken down?
It releases energy and converts to ADP and a phosphate.
What is phosphorylation?
The process of adding a phosphate group to ADP to regenerate ATP.
What is glucose metabolism?
The process of extracting energy from food to produce ATP.
Define autotrophs.
Organisms that make their own food using sunlight, such as plants and algae.
Define heterotrophs.
Organisms that cannot make food and must consume other organisms.
How much energy passes to the next level of a food chain?
Only about 10% of energy passes to the next level; the rest is lost as heat.
What is a redox reaction?
A chemical reaction involving the transfer of electrons, combining oxidation and reduction.
What is oxidation?
The loss of electrons from a molecule.
What is reduction?
The gain of electrons by a molecule.
What role do electron carriers play in cellular respiration?
They transport high-energy electrons, such as NAD+ and FAD.
What is substrate-level phosphorylation?
The direct transfer of a phosphate to ADP to form ATP; occurs in glycolysis and the Krebs cycle.
What is oxidative phosphorylation?
ATP generation that involves the electron transport chain and chemiosmosis.
What occurs during glycolysis?
converted into 2 pyruvate, producing a net gain of 2 ATP and 2 NADH.
Where does glycolysis take place?
In the cytoplasm.
What are the inputs and outputs of glycolysis?
Input: 1 glucose, 2 ATP; Output: 2 pyruvate, 2 NADH, 4 ATP (net gain 2 ATP).
What happens during the energy investment phase of glycolysis?
Two ATP are used to add phosphate groups to glucose, preparing it for breakdown.
What happens during the energy payoff phase of glycolysis?
Production of 2 NADH and 4 ATP with a net gain of 2 ATP and formation of pyruvate.
What occurs in pyruvate oxidation?
Pyruvate is converted to acetyl-CoA, releasing CO₂ and producing NADH.
Where does pyruvate oxidation take place?
In the mitochondria.
What are the inputs and outputs of pyruvate oxidation?
Input: 2 pyruvate, 2 NAD+, 2 CoA; Output: 2 acetyl-CoA, 2 NADH, 2 CO₂.
What is the Citric Acid Cycle (Krebs Cycle)?
A series of chemical reactions in the mitochondrial matrix that convert acetyl-CoA into CO₂, NADH, FADH2, and ATP.
How many times does the Krebs Cycle run per glucose?
Twice, since each glucose produces 2 acetyl-CoA.
What are the main products of the Citric Acid Cycle per glucose?
2 ATP, 6 NADH, 2 FADH2, and 4 CO₂.
What is the total ATP produced from glycolysis and the Krebs cycle?
4 ATP (2 from glycolysis and 2 from the Krebs cycle).
What happens during oxidative phosphorylation?
ATP is produced using the electron transport chain and chemiosmosis.
What is the role of oxygen in oxidative phosphorylation?
Oxygen acts as the final electron acceptor, forming water.
How is the proton gradient created in the electron transport chain?
Protons are pumped into the intermembrane space as electrons move through the complexes.
What is chemiosmosis?
The process where protons flow back through ATP synthase to produce ATP.
What is the range of ATP yield from oxidative phosphorylation?
30 to 36 ATP per glucose.
What is fermentation?
A metabolic process that regenerates NAD+ in the absence of oxygen.
What occurs during lactic acid fermentation?
Pyruvate is converted to lactate, regenerating NAD+.
Where does lactic acid fermentation occur?
In muscle cells and some bacteria.
What is alcohol fermentation?
A process where pyruvate is converted to ethanol and CO₂, regenerating NAD+.
Where does alcohol fermentation occur?
In yeast.
What are the connections of digestion to cellular respiration?
Carbohydrates, lipids, and proteins can be converted into intermediates that enter glycolysis and the Krebs Cycle.
What regulates cellular respiration?
Mechanisms including hormonal control, enzyme activity, and feedback inhibition.
What impact does glucose-6-phosphate have on glycolysis?
It decreases the activity of hexokinase, slowing down glycolysis.
How does ADP affect the enzyme phosphofructokinase?
Increases the activity, promoting glycolysis.
How do citrate and low pH affect phosphofructokinase?
They decrease its activity and slow down glycolysis.
What regulates pyruvate dehydrogenase?
It is increased by ADP and pyruvate and decreased by acetyl-CoA, ATP, and NADH.
What role does isocitrate dehydrogenase play in the Krebs Cycle?
It is activated by ADP and inhibited by ATP and NADH.
What factors increase α-ketoglutarate dehydrogenase activity?
Calcium ions and ADP.
What happens if ATP levels are high in the electron transport chain (ETC)?
The activity of the ETC decreases.
Where does glycolysis occur?
In the cytoplasm.
What does glycolysis produce in the presence of oxygen?
It produces pyruvate, NADH, and ATP.
What is the main purpose of the proton gradient?
To drive ATP synthesis during chemiosmosis.
How does Lactic Acid Fermentation differ from Alcohol Fermentation?
Lactic acid fermentation converts pyruvate to lactate, while alcohol fermentation produces ethanol.
What are the byproducts of Alcohol fermentation?
Ethanol and carbon dioxide.
How is ATP generated during glycolysis?
By substrate-level phosphorylation.
What function does coenzyme A serve in pyruvate oxidation?
It combines with acetyl groups to form acetyl-CoA.
What must happen to NAD+ during fermentation?
It must be regenerated to allow glycolysis to continue.
What are the end products of glycolysis?
2 pyruvate, 2 NADH, and 2 ATP (net).
How is energy primarily stored in cells?
In NADH and FADH2, rather than in ATP.
What waste products are produced during cellular respiration?
Carbon dioxide and water.