genbio exam 1 def

Neuronal Plasticity

The brain's ability to be modified after birth through remodeling at synapses; activity-dependent.

Short-Term Memory (STM)

Information stored for a short time (seconds to minutes); has a limited capacity of about 7 items.

Long-Term Memory (LTM)

Information that is retained and retrieved into STM; theoretically has an infinite capacity.

Learning

The use of knowledge or experience (memory) to decrease the likelihood of negative outcomes.

Long-Term Potentiation (LTP)

The process of making synapses more efficient at transmitting signals, which facilitates memory formation and retrieval.

Emergent Property

A property of a system that is not present in its individual parts; the whole is greater than the sum of its parts.

Scientific Theory

A broad, well-supported explanation for natural phenomena that leads to accurate predictions.

Scientific Law

A statement of an observable pattern in nature, without an explanation for why it occurs.

Polar Covalent Bond

A covalent bond where electrons are unequally shared, resulting in partial positive and negative charges.

Nonpolar Covalent Bond

A covalent bond where electrons are equally shared between atoms of similar electronegativity.

Ionic Bond

A chemical bond formed by the electrostatic attraction between oppositely charged ions (anions and cations).

Adhesion

The attraction between water molecules and other substances.

Cohesion

The attraction between water molecules and other water molecules.

Functional Group

A specific group of atoms within a molecule that determines its chemical properties and function.

Dehydration Synthesis

A chemical reaction that links monomers together into polymers by removing a water molecule.

Hydrolysis

A chemical reaction that breaks down polymers into monomers by adding a water molecule.

Polymer

A large molecule composed of many repeating monomer subunits.

Phospholipid

An amphipathic lipid molecule that is a major component of all cell membranes.

Amphipathic

Having both hydrophilic and hydrophobic regions.

Denaturation

The process where a protein loses its native 3D shape (and thus its function) due to extreme conditions.

Abiogenesis

The origin of life from non-living matter; the process by which life arises naturally from non-living material.

RNA World Hypothesis

The hypothesis that self-replicating RNA molecules were precursors to current life based on DNA and proteins.

Protocell

An aggregate of abiotically produced organic molecules that exhibits some properties of life, like a membrane and division.

Prokaryotic Cell

A type of cell that lacks a membrane-bound nucleus and other organelles (e.g., bacteria).

Eukaryotic Cell

A type of cell that has a membrane-bound nucleus and other membrane-bound organelles.

Endosymbiotic Theory

The theory that mitochondria and chloroplasts originated as free-living prokaryotes engulfed by a host cell.

Fluid Mosaic Model

The model that describes the plasma membrane as a fluid combination of phospholipids, cholesterol, and proteins.

Selectively Permeable

A property of membranes that allows only certain substances to pass through.

Osmosis

The diffusion of water across a selectively permeable membrane.

Active Transport

The movement of molecules across a membrane against their concentration gradient, requiring energy (ATP).

Passive Transport

The movement of molecules across a membrane down their concentration gradient, without energy input.

Metabolism

The sum of all chemical reactions within an organism.

Anabolic Pathway

A metabolic pathway that consumes energy to build complex molecules from simpler ones.

Catabolic Pathway

A metabolic pathway that releases energy by breaking down complex molecules into simpler ones.

ATP (Adenosine Triphosphate)

The primary energy currency of the cell.

Enzyme

A macromolecule (usually a protein) that acts as a catalyst to speed up a specific chemical reaction.

Activation Energy (EA)

The initial energy required to start a chemical reaction.

Redox Reaction

A chemical reaction involving the complete or partial transfer of one or more electrons from one reactant to another.

Oxidation

The loss of electrons from a substance.

Reduction

The gain of electrons by a substance.

Photosynthesis

The process used by plants and other organisms to convert light energy into chemical energy (sugar).

Chloroplast

The organelle in plant cells where photosynthesis occurs.

Light-Dependent Reactions

The first stage of photosynthesis, which occurs in the thylakoids and converts light energy into chemical energy (ATP and NADPH).

Calvin Cycle

The second stage of photosynthesis, which occurs in the stroma and uses ATP and NADPH to fix carbon dioxide into sugar.

Cellular Respiration

The catabolic pathway that breaks down organic molecules to produce ATP.

Glycolysis

The first stage of cellular respiration, where glucose is split into two molecules of pyruvate in the cytoplasm.

Citric Acid Cycle (Krebs Cycle)

A stage of cellular respiration that completes the breakdown of glucose in the mitochondrial matrix.

Oxidative Phosphorylation

The production of ATP using energy derived from the electron transport chain and chemiosmosis.

Electron Transport Chain (ETC)

A series of protein complexes that transfer electrons and pump protons to create a gradient used for ATP synthesis.

Chemiosmosis

The process of ATP production driven by the flow of protons (H+) down their electrochemical gradient through ATP synthase.

Cell Theory

The theory that all living things are composed of cells, cells are the basic unit of life, and new cells arise from existing cells.