Introductory Biology: Properties of Life, Cell Structure, Chemistry, and Transport

A comprehensive set of vocabulary flashcards covering key topics in introductory biology, including the properties of life, cellular structure and organelles, chemistry of life, biological macromolecules, and membrane transport mechanisms.

Order

A property of life in which organisms are organized structures consisting of one or more cells.

Chemotaxis

The movement of tiny bacteria toward or away from chemical stimuli.

Phototaxis

The movement of tiny bacteria toward or away from light stimuli.

Positive Response

Movement toward a stimulus.

Negative Response

Movement away from a stimulus.

Adaptation

The process by which populations of organisms change over generations to become better suited to their environments.

Homeostasis

The relatively stable internal environment required by an organism to maintain life.

Thermoregulation

The process by which organisms regulate their body temperature to withstand environmental climates.

Taxonomic Group

A classification category used by scientists to group organisms based on shared characteristics.

Domain

The largest taxonomic group used to classify organisms.

Prokaryotic Cell

A simple, single-celled organism that lacks a true nucleus and membrane-bound internal organelles.

Eukaryotic Cell

A complex cell containing a true, membrane-bound nucleus and specialized membrane-enclosed organelles.

Scientific Hypothesis

A suggested explanation for an observation that can be tested, initially having little or no support.

Scientific Theory

A generally accepted explanation supported by extensive scientific testing.

Plasma Membrane

The outer covering of a cell that regulates traffic into and out of the cell.

Cytoplasm

Everything within a cell located outside of the nucleus.

Ribosomes

Cellular structures responsible for making proteins.

Nucleoid Region

The area within a prokaryotic cell where its DNA is concentrated.

Cytoskeleton

A network of protein fibers throughout the cell that provides structural shape, holds organelles, and acts as a transport highway.

Endomembrane System

A network of membrane organelles that functions to manufacture and transport molecules throughout the cell.

Nuclear Envelope

The protective membrane surrounding the nucleus that shields DNA.

Smooth ER

A region of the endoplasmic reticulum that synthesizes lipids and detoxifies drugs, alcohol, and toxins.

Rough ER

A region of the endoplasmic reticulum studded with ribosomes that synthesizes proteins destined for export outside the cell.

Golgi Apparatus

An organelle that sorts, tags, and packages products received from the endoplasmic reticulum into vesicles.

Vesicles

Small membrane pouches used to package and transport molecules within or out of the cell.

Vacuoles

Large membrane pouches that function in storage and may contain substances brought in from outside the cell.

Lysosomes

Organelles containing digestive enzymes that break down waste, old organelles, and engulfed pathogens.

Mitochondria

Energy-converting organelles in eukaryotic cells that convert chemical energy in sugar into chemical energy in ATP.

Chloroplasts

Energy-converting organelles found in plants and some protists that convert light energy into chemical energy stored in sugar.

Cell Wall

A rigid structural layer located outside the plasma membrane in plant cells.

Central Vacuole

A large organelle in plant cells that fills with water to maintain internal pressure and provide structural support.

Element

A basic type of matter that cannot be broken down into simpler chemical substances.

Atom

The smallest particle of an element.

Proton

A positively charged subatomic particle located in the atomic nucleus.

Neutron

A subatomic particle with no charge located in the atomic nucleus.

Electron

A negatively charged subatomic particle orbiting outside the atomic nucleus.

Ion

An atom that has gained or lost an electron, gaining a net charge.

Electrolytes

Ions within the body that carry out essential functions such as muscle contraction, nerve signaling, and fluid balance.

Compound

A substance formed by bonding different elements together, exhibiting unique chemical properties.

Polar Molecule

A molecule with an uneven charge distribution, creating positive and negative regions.

Nonpolar Molecule

A molecule with no distinct electric charges, where charge is distributed evenly.

Solution

A homogeneous liquid mixture made of a solvent and one or more dissolved solutes.

Solvent

The liquid component of a solution that dissolves solute particles.

Solute

The substance dissolved inside a solvent.

pH Scale

A measurement scale of acidity or alkalinity based on relative concentrations of $H^+$ and $OH^-$ ions.

Buffer

A solution containing a weak acid and a weak base that stabilizes body pH by neutralizing added acids or bases.

Dehydration Synthesis

The chemical process by which cells link smaller subunits together to assemble macromolecules.

Hydrolysis

The chemical reaction that breaks macromolecules into smaller subunits during digestion.

Monosaccharide

A single carbohydrate sugar unit, such as glucose or fructose.

Disaccharide

A carbohydrate composed of two joined sugar subunits, such as sucrose, maltose, or lactose.

Polysaccharide

A complex carbohydrate composed of hundreds of linked sugar subunits.

Starch

A straight-chain polysaccharide synthesized by plants for energy storage.

Glycogen

A branched polysaccharide stored in the liver of animals for short-term energy.

Cellulose

An indigestible plant polysaccharide forming cell walls and serving as insoluble fiber.

Lipids

Hydrophobic biological molecules used for long-term energy storage, hormones, and cellular membranes.

Phospholipid

A lipid molecule composed of a hydrophilic head and two hydrophobic tails, forming the structural basis of cell membranes.

Steroids

Lipid molecules structured with fused carbon rings, including cholesterol and sex hormones.

Amino Acids

The 20 distinct building block subunits that link together to form protein chains.

Enzyme

A protein molecule that speeds up chemical reactions in living cells without being consumed.

Active Site

The specific region on an enzyme where reactant molecules bind.

Substrate

The reactant molecule that binds to the active site of an enzyme.

Nucleic Acids

Biological macromolecules, including DNA and RNA, that store and handle genetic information.

Nucleotides

The building block subunits of nucleic acids, each containing a specific nitrogenous base.

Phospholipid Bilayer

A double layer of phospholipids in cell membranes with hydrophobic tails facing inward and hydrophilic heads facing outward.

Selectively Permeable

A membrane property allowing specific substances to pass through while blocking others.

Channel Proteins

Transport proteins that allow specific polar or charged molecules to cross the cell membrane.

Receptor Proteins

Membrane proteins that detect external signals and transmit corresponding messages inside the cell.

Glycoproteins

Membrane proteins with attached carbohydrate chains that serve as cell recognition ID tags.

Diffusion

The passive movement of molecules from high concentration to low concentration down a concentration gradient.

Passive Transport

Movement of substances across a cell membrane driven by diffusion without requiring cellular energy.

Active Transport

Energy-requiring movement of substances across a cell membrane against their concentration gradient using ATP.

Facilitated Diffusion

Passive transport of polar or charged particles across a membrane assisted by channel proteins.

Osmosis

The passive movement of water across a membrane through channel proteins toward higher solute concentrations.

Tonicity

The relative solute concentration of a solution surrounding a cell.

Hypotonic Solution

A solution with a lower solute concentration relative to another solution.

Hypertonic Solution

A solution with a higher solute concentration relative to another solution.

Isotonic Solution

A solution with an equal solute concentration relative to another solution.

Endocytosis

A transport process in which a membrane pouch engulfs substances to bring them into the cell.

Exocytosis

A transport process in which a membrane pouch fuses with the plasma membrane to export materials out of the cell.