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Questions and Answers
What drives the generation of ATP in mitochondria according to the chemiosmotic theory?
What drives the generation of ATP in mitochondria according to the chemiosmotic theory?
Why is ATP not considered a good long-term energy store?
Why is ATP not considered a good long-term energy store?
What happens to the protons after they pass through the ATP synthase complexes?
What happens to the protons after they pass through the ATP synthase complexes?
What occurs as electrons move along the electron transport chain in mitochondria?
What occurs as electrons move along the electron transport chain in mitochondria?
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Which statement accurately describes the state of ATP in cells?
Which statement accurately describes the state of ATP in cells?
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What is the net yield of ATP from one glucose molecule undergoing glycolysis?
What is the net yield of ATP from one glucose molecule undergoing glycolysis?
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In anaerobic conditions, pyruvate produced by glycolysis can be converted into which of the following?
In anaerobic conditions, pyruvate produced by glycolysis can be converted into which of the following?
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What occurs during the link reaction when oxygen is present?
What occurs during the link reaction when oxygen is present?
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Which compound acts as an acceptor of the 2C fragment from acetyl coenzyme A in the Krebs cycle?
Which compound acts as an acceptor of the 2C fragment from acetyl coenzyme A in the Krebs cycle?
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What is the role of NAD and FAD in the Krebs cycle?
What is the role of NAD and FAD in the Krebs cycle?
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What is the role of the enzyme complex pyruvate dehydrogenase?
What is the role of the enzyme complex pyruvate dehydrogenase?
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How many sub-units are involved in the enzyme complex pyruvate dehydrogenase?
How many sub-units are involved in the enzyme complex pyruvate dehydrogenase?
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What is the role of dehydrogenase enzymes in the process described?
What is the role of dehydrogenase enzymes in the process described?
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What happens to NAD when it combines with hydrogen ions and electrons?
What happens to NAD when it combines with hydrogen ions and electrons?
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Which of the following is NOT a function of the Krebs cycle?
Which of the following is NOT a function of the Krebs cycle?
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What is the ultimate product generated from the breakdown of macromolecules in the Krebs cycle?
What is the ultimate product generated from the breakdown of macromolecules in the Krebs cycle?
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What type of energy production occurs as a result of the electron transport chain in respiration?
What type of energy production occurs as a result of the electron transport chain in respiration?
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Which institution is responsible for carrying an acetyl group to the Krebs cycle?
Which institution is responsible for carrying an acetyl group to the Krebs cycle?
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What important role does the Krebs cycle play in cellular metabolism?
What important role does the Krebs cycle play in cellular metabolism?
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How does NADH contribute to cellular respiration?
How does NADH contribute to cellular respiration?
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What is regenerated at the end of the Krebs cycle to allow continuous operation?
What is regenerated at the end of the Krebs cycle to allow continuous operation?
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Where does oxidative phosphorylation occur in eukaryotic cells?
Where does oxidative phosphorylation occur in eukaryotic cells?
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What is the role of oxygen in oxidative phosphorylation?
What is the role of oxygen in oxidative phosphorylation?
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What process is primarily utilized by ATP synthase to produce ATP?
What process is primarily utilized by ATP synthase to produce ATP?
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Which of the following accurately describes the structure of mitochondria?
Which of the following accurately describes the structure of mitochondria?
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What happens to protons during oxidative phosphorylation?
What happens to protons during oxidative phosphorylation?
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Which components are located on the cristae of mitochondria?
Which components are located on the cristae of mitochondria?
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What is the significance of the large surface area provided by cristae in mitochondria?
What is the significance of the large surface area provided by cristae in mitochondria?
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During oxidative phosphorylation, what is primarily released as electrons pass through the electron transport system?
During oxidative phosphorylation, what is primarily released as electrons pass through the electron transport system?
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How do electrons contribute to ATP production in oxidative phosphorylation?
How do electrons contribute to ATP production in oxidative phosphorylation?
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Study Notes
Energy and Respiration
- Living organisms require energy to survive. This energy originates from the Sun or chemicals.
- Plants utilize solar energy in photosynthesis to create organic molecules from water and carbon dioxide.
- Animals break down organic molecules to produce adenosine triphosphate (ATP), the energy source for life processes.
- Energy is the ability to do work. It exists in kinetic and potential forms.
- Kinetic energy is energy of motion.
- Potential energy is stored energy. Examples include a stone on a hill or stored chemical energy.
- Energy exists in various forms like light, heat, sound, etc.
- Organisms need energy for anabolism (building complex molecules), movement (internal and external), active transport, maintenance and repair of cells, and maintaining body temperature (in endotherms).
Laws of Thermodynamics
- The first law states that energy cannot be created or destroyed, only transformed.
- The second law states that disorder (entropy) in the universe always increases. Order has less energy.
Activation Energy
- Chemical reactions require activation energy to start.
- Catalysts (e.g., enzymes) reduce the activation energy, enabling faster reaction rates or operation at lower temperatures
- Reactions can be exergonic (releasing energy) or endergonic (requiring energy).
Adenosine Triphosphate (ATP)
- ATP is the universal energy currency in cells.
- ATP is produced in mitochondria and chloroplasts.
- ATP's suitability as the energy currency is due to: rapid energy release, ease of transport, and fast regeneration from ADP.
- ATP is a small, water-soluble molecule, easily transported and involved in cellular reactions.
- The three phosphate groups in ATP are crucial. They are negatively charged, repel each other, and have a low activation energy, making them easily broken to release large amounts of energy.
Role of ATP
- ATP provides energy for anabolic processes (building complex molecules), movement, active transport across membranes, maintenance of cellular components, and body temperature regulation.
Role of Coenzymes
- Coenzymes, such as NAD (nicotinamide adenine dinucleotide) and FAD (flavine adenine dinucleotide) carry hydrogen atoms and electrons in metabolic pathways.
- NAD and FAD store energy from reactions and carry hydrogen, which is critical for energy production in oxidative phosphorylation.
- Coenzymes are frequently found as part of larger enzyme complexes.
Respiration - Glycolysis
- Glycolysis is the anaerobic breakdown of glucose into pyruvate.
- Glycolysis occurs in the cytoplasm of cells.
- It involves a series of 10 enzyme-controlled reactions that break down glucose (a 6-carbon molecule) into two molecules of pyruvate (a 3-carbon molecule), producing a small amount of ATP during substrate-level phosphorylation.
- Glycolysis yields a net gain of 2 ATP molecules and 2 NADH molecules.
- The process involves phosphorylation, splitting the sugar into two smaller units and oxidation.
Link Reaction and Krebs Cycle
- The link reaction connects glycolysis to the Krebs cycle.
- Pyruvate from glycolysis is converted into acetyl-CoA. This occurs in the mitochondrial matrix.
- Krebs Cycle: Acetyl-CoA enters the Krebs cycle, releasing carbon dioxide.
- The Krebs cycle generates reduced coenzymes (NADH and FADH₂) and a small amount of ATP (via substrate-level phosphorylation). It occurs in the matrix of the mitochondria.
Oxidative Phosphorylation
- Oxidative phosphorylation is the final stage of aerobic respiration.
- It occurs in the inner mitochondrial membrane.
- It involves an electron transport chain (ETC) where energy stored in NADH and FADH₂ is used to pump protons (H+) across the inner mitochondrial membrane to create an electrochemical gradient.
- The flow of these protons back into the mitochondria through ATP synthase drives ATP synthesis. This is a process called chemiosmosis.
- Oxygen is the final electron acceptor, forming water.
Anaerobic Respiration
- Anaerobic respiration occurs when oxygen is not available.
- In alcoholic fermentation (e.g., yeast), pyruvate is converted to ethanol and carbon dioxide, regenerating NAD+.
- In lactic acid fermentation (e.g., muscles), pyruvate is converted to lactate, regenerating NAD+.
- Anaerobic respiration results in a significantly lower ATP yield compared with aerobic respiration.
Measurement of Respiration (Respiratory Quotient)
- Respirometers are used to measure the rate of respiration.
- The respiratory quotient (RQ) is the ratio of carbon dioxide produced to oxygen consumed.
- Different respiratory substrates (e.g., carbohydrates, fats, proteins) have different RQs, allowing deductions about the types of molecules being broken down for energy.
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Description
Test your knowledge on energy sources and respiration in living organisms. This quiz covers topics such as photosynthesis, ATP production, and the laws of thermodynamics. Explore the different forms of energy and how organisms utilize them for various life processes.
