Cellular Respiration Flashcards

Redox Reactions

• Redox reactions involve the transfer of electrons between reactants, critical for energy production.
• Oxidation refers to a substance losing electrons, while reduction involves a substance gaining electrons.

Agents in Redox Reactions

• An oxidizing agent gains electrons, increasing the charge of the substance it acts upon.
• A reducing agent donates electrons, resulting in a reduction of charge for the substance it interacts with.

Cellular Respiration Processes

• Oxidative phosphorylation combines oxidation and phosphorylation, primarily generating ATP from the energy of redox reactions.
• The electron transport chain facilitates energy transfer to produce ATP from ADP and inorganic phosphate (Pi).
• Key electron carriers include NADH and FADH2, which play vital roles in energy transfer.

Mitochondrial Structure

• Mitochondria, known as the powerhouse of the cell, contain cristae that increase surface area for energy production.
• The intermembrane space separates the inner mitochondrial membrane from the outer membrane, while the mitochondrial matrix is the fluid within the inner membrane.

Key Metabolic Pathways

• Glycolysis splits glucose into pyruvate, yielding a small amount of ATP.
• The citric acid cycle completes the breakdown of glucose, generating ATP, NADH, FADH2, and CO2 in a series of eight steps.

Respiration Types

• Aerobic respiration requires oxygen for the complete breakdown of organic molecules, producing significant ATP.
• Anaerobic respiration occurs without oxygen, resulting in less energy yield and two main types of fermentation: alcohol and lactic acid.

ATP Generation

• Each NADH contributes approximately 2.5 ATP, while each FADH2 contributes about 1.5 ATP due to their different points of entry in the electron transport chain.
• The total ATP yield from the breakdown of one glucose molecule can range from 32 to 36 ATP, depending on cellular conditions.

Glycolysis and Other Reactions

• Glycolysis occurs in the cytoplasm, while conversion of pyruvate to acetyl CoA and the citric acid cycle happen in mitochondria.
• In glycolysis, glucose is transformed into pyruvate, generating ATP and NADH.

Fermentation and Efficiency

• Fermentation processes help regenerate NAD+ necessary for glycolysis to continue, despite not generating additional ATP.
• Compared to aerobic respiration, fermentation is less efficient, yielding fewer ATP due to incomplete glucose breakdown.

Cellular Energy Utilization

• During intense exercise, quick ATP sources diminish, leading to reliance on anaerobic processes.
• Once blood glucose is depleted, the body utilizes stored glycogen and eventually turns to fats and proteins for energy.

Metabolic Regulation

• Feedback inhibition prevents excessive ATP production when energy supplies are sufficient, maintaining cellular homeostasis.
• Precursor metabolites are crucial for synthesizing macromolecules and energizing cellular metabolism.

Glucose Regulation

• Converting glucose to pyruvate helps regulate blood glucose levels and prevent hypoglycemia.
• The degradation of glycogen also plays a role in maintaining stable blood sugar levels.