Biology Chapter 5 Flashcards

Enzymatic and Cellular Mechanisms

• Active Site: Location on an enzyme where a substrate binds, allowing for chemical reactions to occur.
• Enzyme: Proteins or RNA that act as biological catalysts, accelerating chemical reactions without being consumed.
• Competitive Inhibitor: Mimics substrate and binds to the active site, blocking enzyme activity.

Transport Mechanisms

• Active Transport: Movement of substances against their concentration gradient, requiring energy (often ATP) and specific transport proteins.
• Facilitated Diffusion: Involves specific transport proteins to move substances across membranes along their concentration gradient.
• Endocytosis: Process of cellular uptake by forming vesicles from the plasma membrane.
• Exocytosis: Release of materials from a cell via vesicles fusing with the plasma membrane.

Energy and Metabolism

• Adenosine Triphosphate (ATP): Primary energy carrier in cells.
• Cellular Respiration: Aerobic process that converts food molecules into usable energy, involving glycolysis, the citric acid cycle, and oxidative phosphorylation.
• Energy Coupling: Utilizing energy released from exergonic reactions to fuel endergonic reactions.
• Chemical Energy: Potential energy stored in molecules, released during chemical reactions.
• Exergonic Reaction: Energy-releasing reaction where products have less potential energy than reactants.
• Endergonic Reaction: Energy-consuming reaction that yields products with higher potential energy.

Concentration and Gradients

• Concentration Gradient: Variation in chemical substance density across areas, influencing substance movement.
• Diffusion: Spontaneous process where substances move from areas of high concentration to low concentration.

Thermodynamics and Entropy

• First Law of Thermodynamics: Energy conservation principle; energy cannot be created or destroyed, only transformed.
• Entropy: Measure of disorder; associated with energy transformations, particularly heat as random molecular motion.

Biochemical Factors and Control

• Coenzyme: Organic molecule that functions as a cofactor, often derived from vitamins, essential for enzymatic activity.
• Cofactor: Nonprotein molecule or ion necessary for enzyme function.
• Feedback Inhibition: Self-regulatory mechanism where the end product of a pathway inhibits an earlier enzyme, controlling metabolic processes.

Biological Membranes

• Fluid Mosaic Model: Describes the dynamic structure of cellular membranes, comprised of diverse proteins in a flexible phospholipid bilayer.

Heat

• Heat: Form of thermal energy associated with molecular movement; represents energy in its most random state.