Bioenergetics Overview Quiz

Bioenergetics

• Bioenergetics is the transfer and utilization of energy in biological systems
• Bioenergetics predicts if a process is possible, whereas kinetics measures the reaction rate.
• Enzymes don't create reactions, they catalyze them.

Learning Objectives

• Describe bioenergetics: Define bioenergetics as the transfer and utilization of energy in biological systems.
• Discuss energetics in metabolic reactions: Explain how energetics affects the possibility of a metabolic reaction.
• List the ATP production ways.
• List pathways of glucose inside the cell: Outline the various pathways glucose takes within a cell.
• Describe both glycolysis and gluconeogenesis: Explain the steps and purpose of these pathways.
• Explain the pentose phosphate pathway: Describe the functions and importance of the pentose phosphate pathway.
• Describe both glycogenolysis and glycogenesis: Differentiate glycogenolysis (breakdown) and glycogenesis (synthesis).
• Explain the Citric acid cycle and electron transport chain: Describe the steps of these crucial processes in cellular respiration.

Free Energy and Energetics

• Change in energy during a reaction is represented by the change in free energy (ΔG)
• If ΔG is negative, the process is spontaneous (exergonic).
• If ΔG is positive, the process is non-spontaneous (endergonic)
• Enzymes do not change ΔG, they facilitate reactions.

ATP Production

• Substrate-level phosphorylation: ATP made during metabolic reactions.
• Oxidative phosphorylation: Requires transfer of electrons, ATP is generated via an electrochemical gradient.

Carbohydrate Metabolism

• Central roles Glycogen, Glucose 6-phosphate, Glycolysis, Gluconeogenesis, and Pentose Phosphate Pathway, in the storage and use of carbohydrates in the body.
• Glycolysis generates ATP and other metabolites for diverse metabolic needs.
• Gluconeogenesis is a pathway that synthesizes glucose from various precursors.
• Pentose Phosphate Pathway (also called the phosphogluconate pathway) generates NADPH and ribose-5-phosphate for nucleotide synthesis.

Hormonal Regulation of Glycolysis

• Insulin and Glucagon are primary hormones regulating glycolysis.
• Insulin stimulates glycolysis whereas glucagon hinders it.

Glycolysis- NAD+ Regeneration

• NAD+ is re-generated during fermentation(in absence of oxygen)
• Fermentation produces lactate or ethanol to regenerate NAD+
• Glycolysis can't happen without NAD+ when no oxygen is available.

Citric Acid Cycle (TCA Cycle)

• TCA cycle occurs in mitochondria.
• Pyruvate is transported into the mitochondria.
• The cycle converts Acetyl CoA into CO2.
• Produces NADH and FADH₂ that feed the electron transport chain

Oxidative Phosphorylation and ETC

• NADH and FADH₂ carry high-energy electrons to the electron transport chain (ETC).
• The ETC uses the energy from electrons to pump protons (H⁺) across a membrane.
• This proton gradient drives ATP synthesis.

Electron Transport Chain

• Electrons carried by NADH and FADH₂ are used to reduce oxygen to water.
• ETC complexes pump H+ to outer membrane.
• A positive charge gradient forms, driving ATP synthesis.

Pentose Phosphate Pathway

• Main products include Ribose 5-phosphate and NADPH.
• It plays an important role in nucleotide and nucleic acid synthesis.
• Related to other metabolic pathways such as glycolysis, and gluconeogenesis.
• Oxidative reactions generate NADPH
• Non-oxidative reactions produce intermediates useful for other pathways such as ribose-5-phosphate.

Transfer of Cytoplasmic NADH to Mitochondria

• NADH from cytoplasm enters mitochondria through shuttles (Malate-aspartate or Glycerol-3-phosphate) to maintain redox balance.
• Necessary for ATP production and other metabolic needs.

Glycogen Metabolism and Storage

• Glycogen is a storage form of glucose.
• Synthesized from glucose-1-phosphate via UDP-glucose.
• Broken down to glucose-1-phosphate for energy needs.

Energy Gained from 1 Mol Glucose

• Net energy yield from the oxidation of 1 mole of glucose varies based on shuttle systems used to transport cytosolic NADH.
• Glycolysis, pyruvate oxidation, Citrate Cycle (TCA) and the Electron Transport Chain (ETC).

Other Important Points

• Learning Objectives from presentation
• Specific Enzymes and their roles within pathways
• Different metabolic pathways and processes
• Regulation of metabolism by hormones (insulin and glucagon)

Test your knowledge on bioenergetics, the transfer and utilization of energy in biological systems. This quiz covers metabolic reactions, ATP production, glycolysis, gluconeogenesis, and more important pathways related to energy management in cells. Enhance your understanding of how energy dynamics influence biological processes.