CHAPTER 3 Energy and Cellular Respiration

Flashcards covering key vocabulary from Chapter 3 lecture notes focusing on energy, metabolism, and cellular respiration.

Metabolism

The sum of all chemical reactions that occur within a cell, enabling it to grow, reproduce, maintain its structures, and respond to the environment. It involves both catabolism (breaking down molecules) and anabolism (building molecules).

Metabolic Pathway

A linked series of chemical reactions occurring within a cell. Reactants, products, and intermediates are all involved, typically with each reaction catalyzed by an enzyme. These pathways can be catabolic (leading to energy release) or anabolic (leading to energy storage).

Catabolism

The breakdown of complex molecules into simpler ones, often releasing energy. Examples include the breakdown of glucose into pyruvate during glycolysis, which releases energy stored in the chemical bonds of glucose.

Anabolism

The synthesis of complex molecules from simpler ones, requiring an input of energy. An example is the synthesis of proteins from amino acids, which requires ATP.

Energy

The capacity to cause change or perform work. It exists in various forms, such as kinetic energy (energy of motion) and potential energy (stored energy).

Kinetic Energy

The energy possessed by an object due to its motion. Examples include the movement of molecules, the rotation of a turbine, and the flight of an airplane.

Potential Energy

Energy that is stored in the position or state of an object. Examples include gravitational potential energy (due to height) and chemical potential energy (stored in chemical bonds).

Bond Energy

The energy required to break or form a chemical bond. It's a measure of the stability of a chemical bond; stronger bonds have higher bond energies.

Thermodynamics

The study of energy transformations that occur in a collection of matter. It provides insights into the flow and conversion of energy from one form to another.

Entropy

A measure of the disorder or randomness in a system. According to the second law of thermodynamics, entropy tends to increase in an isolated system.

Free Energy

The portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system. It's the energy available for a chemical reaction to do useful work.

Endergonic

A reaction that absorbs free energy from its surroundings. These reactions require energy input to proceed and result in products with higher free energy than the reactants.

Exergonic

A reaction that proceeds with a net release of free energy and is spontaneous. The products have less free energy than the reactants.

Aerobic Respiration

A type of cellular respiration that requires oxygen to generate energy (ATP). It involves the complete oxidation of glucose to carbon dioxide and water.

Substrate Level Phosphorylation

The formation of ATP by directly transferring a phosphate group from a substrate molecule to ADP. This process occurs during glycolysis and the Krebs cycle.

Glycolysis

A metabolic pathway that breaks down glucose into two molecules of pyruvate, producing ATP and NADH. It occurs in the cytoplasm and does not require oxygen.

Krebs Cycle

A cyclic metabolic pathway that oxidizes acetyl-CoA, producing ATP, NADH, and FADH2, and releasing carbon dioxide. It occurs in the mitochondrial matrix.

Oxidative Phosphorylation

The process in which ATP is synthesized by using the energy released during the electron transport chain and chemiosmosis. It occurs in the inner mitochondrial membrane.

Electron Transport Chain

A series of protein complexes that transfer electrons from electron donors to electron acceptors via redox reactions, coupling this electron transfer with the transfer of protons (H+) across a membrane.

Chemiosmosis

The movement of ions across a semipermeable membrane, down their electrochemical gradient. More specifically, it relates to the creation of ATP by the movement of hydrogen ions across a membrane during cellular respiration or photosynthesis.

Anaerobic Respiration

A metabolic process that breaks down glucose in the absence of oxygen. It uses a final electron acceptor other than oxygen for the electron transport chain.

Fermentation

A metabolic process that converts sugars to acids, gases, or alcohol in the absence of