Energetics of Living Systems

These flashcards cover key vocabulary terms and concepts from the lecture on energetics of living systems, including definitions and examples.

Kinetic Energy

Energy associated with motion.

Potential Energy

Stored energy based on position or structure.

Redox Reactions

Involve transfer of electrons between molecules; one is oxidized and the other is reduced.

Oxidation

Process that loses electrons, usually releasing energy.

Reduction

Process that gains electrons, usually storing energy.

First Law of Thermodynamics

Energy cannot be created or destroyed, only transformed.

Second Law of Thermodynamics

Energy transformations are not 100% efficient; some energy becomes unusable.

Gibbs Free Energy (ΔG)

Determines whether a reaction will occur spontaneously.

Exergonic Reaction

Reaction that releases energy and is spontaneous.

Endergonic Reaction

Reaction that requires energy input and is non-spontaneous.

Activation Energy (Ea)

The energy required to start a chemical reaction.

Enzyme

A biological catalyst, usually a protein, that speeds up a reaction without being consumed.

Induced Fit Model

The concept that an enzyme changes shape slightly to optimize the fit with the substrate.

Competitive Inhibition

Inhibitor resembles substrate and competes for the active site.

Noncompetitive Inhibition

Inhibitor binds to allosteric site, changing enzyme shape and reducing activity.

Biochemical Pathway

A series of enzyme-catalyzed reactions where the product of one step is the substrate for the next.

Feedback Inhibition

The end product of a pathway inhibits an enzyme early in the pathway.

ATP

Adenosine triphosphate; primary energy currency of the cell.

Phosphorylation

The process of adding a phosphate group to a protein, changing its shape/function.

Autotrophs

Organisms that produce their own organic molecules using inorganic sources.

Heterotrophs

Organisms that obtain organic molecules by consuming other organisms.

Electron Transport Chain (ETC)

A series of protein complexes that transfer electrons and pump H⁺ ions to create ATP.

Chemiosmosis

Process where H⁺ ions flow back through ATP synthase, driving the production of ATP.

Fermentation

A process to regenerate NAD⁺ for glycolysis by converting pyruvate into lactate or ethanol.

Photosynthesis

The process of converting light energy into chemical energy (glucose).

Calvin Cycle

Light-independent reactions that convert CO₂ into glucose using ATP and NADPH.

Nucleotide

Unit of DNA composed of a phosphate group, deoxyribose sugar, and nitrogen base.

Transcription

Process of synthesizing RNA from a DNA template.

Translation

Process of synthesizing proteins from mRNA at the ribosome.

Mutation

A change in the DNA sequence that can affect protein structure/function.