Biology Foundations – Chapters 1 to 5 Vocabulary

Vocabulary flashcards summarizing key terms and definitions from Chapters 1–5 lecture notes on biology, chemistry of life, macromolecules, cell structure, and membrane transport.

Biology

The scientific study of living organisms and life processes.

Properties of Life

Shared traits of organisms: cellular organization, complexity, response to environment, growth & reproduction, energy use, homeostasis, and evolutionary adaptation.

Hierarchical Organization

Levels of biological structure: cellular, organismal, populational, ecosystem, biosphere.

Emergent Property

A new characteristic that arises at a higher level of organization that is absent at lower levels.

Scientific Method

Systematic process: observation, hypothesis, prediction, experimentation, results, conclusion.

Deductive Reasoning

Logic that applies general principles to predict specific results.

Inductive Reasoning

Logic that uses specific observations to formulate general principles.

Hypothesis

A tentative, testable explanation for an observation.

Scientific Theory

A well-supported, interconnected set of concepts explaining wide-ranging observations.

Evolution

Genetic change in populations over generations; descent with modification.

Natural Selection

Process where individuals with advantageous traits survive and reproduce more successfully.

Fitness (Biology)

Reproductive success of an individual relative to others in the population.

Fossil Record

Preserved remains providing chronological evidence for evolutionary change.

Homologous Structures

Anatomical features with common evolutionary origin but possibly different functions.

Analogous Structures

Features with similar function but independent evolutionary origins.

Vestigial Structure

A reduced or unused anatomical feature inherited from ancestors.

Comparative Embryology

Study of embryo development to reveal evolutionary relationships.

Molecular Evidence

Comparisons of DNA or protein sequences to infer evolutionary history.

Atom

Smallest unit of an element, composed of protons, neutrons, and electrons.

Proton

Positively charged subatomic particle in the atomic nucleus.

Neutron

Neutral subatomic particle in the atomic nucleus.

Electron

Negatively charged particle occupying orbitals around the nucleus.

Atomic Number

Number of protons in an atom; defines the element.

Atomic Mass

Total mass of protons and neutrons in an atom.

Isotope

Atoms of the same element with different numbers of neutrons.

Ion

Charged atom or molecule produced by the loss or gain of electrons.

Orbital

Three-dimensional region where an electron is most likely found.

Energy Level

Discrete electron energy shell around the nucleus.

Octet Rule

Atoms tend to obtain eight electrons in the valence shell for stability.

Electronegativity

Atom’s affinity for shared electrons in a bond.

Covalent Bond

Chemical bond formed by sharing electron pairs.

Nonpolar Covalent Bond

Equal sharing of electrons between atoms.

Polar Covalent Bond

Unequal sharing of electrons, creating partial charges.

Ionic Bond

Electrostatic attraction between oppositely charged ions.

Hydrogen Bond

Weak attraction between a hydrogen in a polar bond and an electronegative atom.

Hydrophobic Interaction

Clustering of nonpolar molecules in water to minimize disruption of hydrogen bonds.

van der Waals Force

Weak attraction due to transient electron cloud polarizations.

Chemical Reaction

Formation or breaking of chemical bonds producing new substances.

Cohesion

Water molecules sticking to each other via hydrogen bonds.

Adhesion

Water molecules sticking to other polar surfaces.

Specific Heat

Energy required to raise 1 g of a substance 1 °C; high for water.

Heat of Vaporization

Energy needed to convert liquid to gas; high for water, enabling cooling.

Solvent (Water)

Water’s ability to dissolve polar and ionic substances via hydration shells.

Hydrophilic

Having affinity for water; polar.

Hydrophobic

Water-fearing; nonpolar and insoluble.

Density Anomaly of Ice

Solid water is less dense than liquid due to lattice hydrogen bonding.

pH

Negative logarithm of hydrogen ion concentration; measures acidity/basicity.

Acid

Substance that releases H⁺ ions, lowering pH.

Base

Substance that accepts H⁺ or releases OH⁻, raising pH.

Buffer

Pair of chemicals that resist pH change by donating or accepting H⁺.

Dehydration Synthesis

Reaction that joins monomers by removing water.

Hydrolysis

Reaction that breaks polymers by adding water.

Monomer

Small subunit that serves as building block of polymers.

Polymer

Large molecule made of repeating monomers.

Carbohydrate

Organic compound with 1:2:1 C:H:O ratio; energy source and structural roles.

Monosaccharide

Single sugar monomer; e.g., glucose.

Disaccharide

Two monosaccharides linked via dehydration; e.g., sucrose.

Polysaccharide

Long chain of monosaccharides; storage or structural.

Starch

Plant storage polysaccharide of α-glucose.

Glycogen

Animal storage polysaccharide of branched α-glucose.

Cellulose

Plant cell-wall polysaccharide of β-glucose; structural.

Chitin

Structural polysaccharide with nitrogen; in fungi and arthropod exoskeletons.

Nucleotide

Monomer of nucleic acids: sugar + phosphate + nitrogenous base.

DNA

Double-helix nucleic acid storing hereditary information; bases A,T,C,G.

RNA

Single-strand nucleic acid involved in gene expression; bases A,U,C,G.

ATP

Adenosine triphosphate; cell’s primary energy currency.

Amino Acid

Monomer of proteins; contains amino, carboxyl, hydrogen, and R group.

Peptide Bond

Covalent bond joining amino acids in proteins.

Primary Structure

Linear sequence of amino acids in a polypeptide.

Secondary Structure

Regular coils (α-helix) or sheets (β-pleated) via backbone hydrogen bonds.

Tertiary Structure

Three-dimensional folding of a single polypeptide.

Quaternary Structure

Association of multiple polypeptide subunits into a functional protein.

Denaturation

Loss of protein structure and function due to environmental stress.

Chaperone Protein

Molecule aiding correct folding of other proteins.

Lipid

Hydrophobic biomolecule including fats, phospholipids, steroids, terpenes.

Triglyceride

Energy-storage fat of glycerol plus three fatty acids.

Phospholipid

Glycerol, two fatty acids, and phosphate head; amphipathic membrane component.

Micelle

Spherical aggregate of phospholipids with hydrophobic tails inward.

Phospholipid Bilayer

Two-layered sheet forming basic structure of biological membranes.

Cell Theory

All organisms are composed of cells, cells are basic units of life, cells arise from existing cells.

Prokaryote

Cell lacking nucleus and membrane-bound organelles; bacteria and archaea.

Eukaryote

Cell with nucleus and membrane-bounded organelles.

Organelle

Membrane-bounded compartment with specialized function in eukaryotes.

Nucleus

Organelle housing linear chromosomes; bound by double membrane with pores.

Ribosome

rRNA-protein complex that synthesizes polypeptides from mRNA.

Endomembrane System

Interconnected membranes: nuclear envelope, ER, Golgi, lysosomes, vesicles.

Rough Endoplasmic Reticulum

ER studded with ribosomes; synthesizes proteins for export or membranes.

Smooth Endoplasmic Reticulum

ER without ribosomes; lipid synthesis and Ca²⁺ storage.

Golgi Apparatus

Stack of membranes modifying, sorting, and packaging proteins and lipids.

Lysosome

Vesicle with hydrolytic enzymes for intracellular digestion and recycling.

Mitochondrion

Double-membrane organelle producing ATP via oxidative metabolism; contains its own DNA.

Chloroplast

Plant organelle performing photosynthesis; contains thylakoid membranes and DNA.

Cytoskeleton

Dynamic protein fiber network providing structure and movement.

Microfilament (Actin)

Thin filaments aiding cell shape, movement, and contraction.

Microtubule

Tubulin cylinders organizing cell, guiding vesicles, and forming spindle & flagella.

Intermediate Filament

Durable fibers providing mechanical stability to cells.

Centrosome

Microtubule-organizing center containing a pair of centrioles in animal cells.

Flagellum

Long whip-like appendage with 9+2 microtubule arrangement for motility.

Extracellular Matrix (ECM)

Network of secreted glycoproteins and fibers supporting animal cells.

Tight Junction

Seal between adjacent animal cells preventing leakage.