General Biology - Lessons 1 to 5 Comprehensive Vocabulary Flashcards

Vocabulary flashcards covering key terms and concepts across all five lessons, including the scientific method, chemistry of life, biological macromolecules, cell structure/organelles, and membrane transport processes.

Science

Knowledge that covers general truths or the operation of general laws, especially when acquired and tested by the scientific method.

Scientific Method

A method of research with defined steps that include careful observation, formulation of a hypothesis, testing, and confirming or falsifying the hypothesis.

Hypothesis

A suggested and testable explanation for an event or observation.

Theory

A tested and confirmed explanation for observations or phenomena.

Inductive Reasoning

A form of logical thinking that uses related observations to arrive at a general conclusion.

Deductive Reasoning

A form of logical thinking that uses a general principle or law to predict specific results.

Basic Science

Science that seeks to expand knowledge and understanding regardless of short-term practical application.

Applied Science

A form of science that aims to use scientific knowledge to solve real-world problems.

Homeostasis

The ability of an organism to maintain constant, stable internal conditions required to sustain life.

Atom

The smallest and most fundamental unit of matter that retains all the chemical properties of an element.

Element

A unique form of matter with specific chemical and physical properties that cannot break down into smaller substances by ordinary chemical reactions.

Atomic Number

The total number of protons in an atom, which distinguishes one element from another.

Mass Number

The total number of protons and neutrons in an atom.

Isotopes

Different forms of the same element that have the same number of protons but a different number of neutrons.

Half-Life

The time required for half of the original concentration of an isotope to decay back to a more stable form.

Octet Rule

The principle that atoms are most stable energetically when they hold eight electrons in their valence shell (outermost electron shell).

Cation

A positively charged ion formed by an atom losing one or more electrons.

Anion

A negatively charged ion formed by an atom gaining one or more electrons.

Ionic Bond

A chemical bond formed between ions with opposite charges.

Covalent Bond

A strong chemical bond formed when two atoms share one or more pairs of electrons.

Polar Covalent Bond

A type of covalent bond formed when electrons are shared unequally between atoms, resulting in slightly positive and slightly negative regions.

Nonpolar Covalent Bond

A type of covalent bond formed between atoms when electrons are shared equally.

Electronegativity

The ability of an element to attract electrons towards itself within a chemical bond.

Hydrogen Bond

A weak attraction between a slightly positively charged hydrogen atom and a slightly negatively charged atom in another molecule or region.

Van Der Waals Interactions

Weak physical attractions or interactions between molecules caused by temporary, fluctuating electron densities.

Specific Heat Capacity

The amount of heat required for one gram of a substance to absorb or lose to change its temperature by one degree Celsius.

Heat of Vaporization

The high amount of energy required to convert one gram of a liquid substance into a gas.

Cohesion

Intermolecular attractive forces between water molecules caused by their polar nature, responsible for surface tension.

Adhesion

The attraction between water molecules and other polar or charged molecules.

Buffer

A substance that resists changes in pH by absorbing or releasing hydrogen or hydroxide ions.

Isomers

Molecules that share the same chemical formula but differ in the structure, placement, or spatial arrangement of their atoms and chemical bonds.

Enantiomers

Molecules that share the same chemical structure and bonds but are non-superimposable mirror images of each other.

Functional Group

A specific group of atoms within a molecule that confers consistent, distinct chemical properties to that molecule.

Dehydration Synthesis

A chemical reaction that links monomer molecules together, forming a covalent bond while releasing a water molecule as a byproduct.

Hydrolysis

A chemical reaction that breaks down a polymer into smaller units or monomers through the addition of a water molecule.

Monosaccharide

A single monomer unit of carbohydrates, such as glucose, galactose, or fructose.

Glycosidic Bond

A covalent bond formed between a carbohydrate molecule and another molecule (such as between two monosaccharides) via a dehydration reaction.

Polysaccharide

A long chain of monosaccharides linked by glycosidic bonds, which may be branched or unbranched.

Glycogen

A highly branched storage polysaccharide made of glucose monomers, used by humans and other vertebrates for energy storage in liver and muscle cells.

Cellulose

An unbranched polysaccharide consisting of glucose monomers linked by $\beta\text{ 1-4}$ glycosidic bonds, providing structural support to plant cell walls.

Chitin

A nitrogen-containing polysaccharide made of repeating N-acetyl-$\beta$-d-glucosamine units, forming the exoskeleton of arthropods and the cell walls of fungi.

Triglyceride

A fat molecule consisting of three fatty acid chains attached to a glycerol backbone by ester bonds.

Saturated Fatty Acid

A long-chain hydrocarbon containing only single covalent bonds between carbon atoms, maximizing the number of attached hydrogen atoms.

Unsaturated Fatty Acid

A long-chain hydrocarbon that contains one or more double bonds between carbon atoms, resulting in fewer attached hydrogen atoms.

Phospholipid

An amphipathic lipid consisting of two fatty acid chains and a modified phosphate group attached to a glycerol backbone, forming the major structural component of cell membranes.

Amphipathic

Describing a molecule that contains both a hydrophilic (water-loving) region and a hydrophobic (water-fearing) region.

Peptide Bond

A covalent bond formed between two amino acids by a dehydration synthesis reaction connecting a carboxyl group to an amino group.

Denaturation

The loss of a protein's three-dimensional shape and function caused by changes in temperature, pH, or chemical exposure, without breaking its primary structure.

Primary Structure

The unique linear sequence of amino acids in a polypeptide chain.

Secondary Structure

Local folding patterns within a polypeptide chain formed by hydrogen bonding in the peptide backbone, most commonly the $\alpha$-helix and $\beta$-pleated sheet.

Tertiary Structure

The overall three-dimensional shape of a single polypeptide, determined by chemical interactions among the R groups of amino acids.

Quaternary Structure

The three-dimensional arrangement resulting from the association of two or more individual polypeptide subunits in a multi-subunit protein.

Nucleotide

The monomer of nucleic acids, consisting of a pentose sugar, a nitrogenous base, and one or more phosphate groups.

Phosphodiester Linkage

The covalent bond that holds together polynucleotide chains by linking the $5'$ phosphate group of one nucleotide to the $3'$ hydroxyl group of another.

Magnification

The process of enlarging an object's appearance under microscopy.

Resolving Power

The ability of a microscope to distinguish two adjacent structures as separate entities, determining image clarity and detail.

Unified Cell Theory

The biological concept stating that all living things are composed of one or more cells, the cell is the basic unit of life, and all new cells arise from pre-existing cells.

Prokaryote

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

Eukaryote

An organism whose cells contain a membrane-bound nucleus and other membrane-bound compartmentalized organelles.

Nucleoid

The central, non-membrane-bound region of a prokaryotic cell where its circular chromosomal DNA is located.

Cytoplasm

The entire cellular region between the plasma membrane and the nuclear envelope, consisting of gel-like cytosol, organelles, and cytoskeleton elements.

Organelle

A specialized membrane-bound compartment or sac within a cell that carries out specific functions.

Chromatin

The protein-DNA complex that serves as the building material of eukaryotic chromosomes.

Nucleolus

A condensed region within the nucleus responsible for assembling ribosomal RNA and combining it with proteins to form ribosomal subunits.

Ribosome

A cellular structure composed of RNA and proteins that is responsible for carrying out protein synthesis.

Mitochondria

Double-membrane eukaryotic organelles responsible for cellular respiration and generating ATP, the cell's main energy-carrying molecule.

Peroxisome

A small, round organelle enclosed by a single membrane that carries out oxidation reactions to break down fatty acids and amino acids, and detoxifies poisons.

Endomembrane System

A group of eukaryotic membranes and organelles (including the nuclear envelope, ER, Golgi apparatus, lysosomes, vesicles, and plasma membrane) that work together to modify, package, and transport lipids and proteins.

Rough Endoplasmic Reticulum (RER)

A region of the endoplasmic reticulum studded with ribosomes on its cytoplasmic surface, involved in protein modification and phospholipid synthesis.

Smooth Endoplasmic Reticulum (SER)

A region of the endoplasmic reticulum with few or no ribosomes that synthesizes carbohydrates, lipids, and steroid hormones, detoxifies chemicals, and stores calcium ions.

Golgi Apparatus

A eukaryotic organelle consisting of stacked membranous cisternae that sorts, tags, modifies, and packages lipids and proteins for distribution.

Lysosome

An animal cell organelle containing hydrolytic enzymes that breaks down macromolecules, recycles worn-out organelles, and destroys engulfed pathogens.

Chloroplast

A plant and algal cell organelle containing chlorophyll that carries out photosynthesis to generate glucose and oxygen using light, carbon dioxide, and water.

Endosymbiosis

A mutually beneficial evolutionary relationship where one organism lives inside another, explaining the origin of mitochondria and chloroplasts from prokaryotic ancestors.

Central Vacuole

A large plant cell organelle that regulates storage, holds water, maintains turgor pressure, and aids in cell growth.

Microfilaments

The narrowest cytoskeletal elements, composed of two intertwined strands of actin, providing rigidity, cell shape, and enabling movement.

Intermediate Filaments

Cytoskeletal fibers composed of intertwined strands of fibrous proteins (such as keratin) that bear tension and anchor organelles in place.

Microtubules

The widest cytoskeletal elements, formed by hollow tubes of polymerized $\alpha$-tubulin and $\beta$-tubulin dimers, which resist compression, serve as transport tracks, and form cilia and flagella.

Extracellular Matrix

A network of proteins (such as collagen) and carbohydrates (such as proteoglycans) secreted by animal cells that provides structural support and cell-cell communication.

Plasmodesmata

Microscopic channels passing through adjacent plant cell walls that connect their cytoplasm and allow transport of materials between cells.

Tight Junction

A watertight seal between adjacent animal cells formed by proteins that prevents materials from leaking between them.

Desmosome

A strong spot-weld attachment between adjacent animal epithelial cells formed by cadherins linked to intermediate filaments.

Gap Junction

A protein-lined channel (formed by connexons) between adjacent animal cells that permits water, ions, and small molecules to pass for cellular communication.

Fluid Mosaic Model

A model describing plasma membrane structure as a fluid combination of phospholipids, cholesterol, proteins, and carbohydrates that move relative to one another.

Glycocalyx

The highly hydrophilic carbohydrate coating on the outer surface of plasma membranes formed by the carbohydrate components of glycoproteins and glycolipids.

Passive Transport

A naturally occurring mode of membrane transport that moves substances down their concentration gradient without requiring cellular energy (ATP).

Concentration Gradient

A physical space along which there is a range of varying concentrations of a single substance.

Diffusion

The passive process by which a substance moves from an area of higher concentration to an area of lower concentration until evenly distributed.

Facilitated Transport

The movement of polar or charged molecules across a plasma membrane down their concentration gradient with the assistance of transmembrane channel or carrier proteins.

Osmosis

The diffusion of free water molecules across a semipermeable membrane along water's concentration gradient, inversely proportional to solute concentration.

Osmolarity

The measure of a solution's total solute concentration, expressed in total number of solute particles per unit volume.

Hypertonic

Describing an extracellular solution that has a higher solute concentration (higher osmolarity) than the cell's cytoplasm, causing water to leave the cell.

Hypotonic

Describing an extracellular solution that has a lower solute concentration (lower osmolarity) than the cell's cytoplasm, causing water to enter the cell.

Isotonic

Describing an extracellular solution that has the same solute concentration (same osmolarity) as the cell's cytoplasm, resulting in no net movement of water.

Electrochemical Gradient

The combined effect of a concentration gradient and an electrical charge difference across a membrane that influences the movement of an ion.

Active Transport

The movement of a substance across a membrane against its concentration or electrochemical gradient, requiring cellular energy (usually ATP).

Primary Active Transport

Active transport that directly uses ATP to move ions across a membrane and generate a charge/concentration difference.

Secondary Active Transport

Active transport that uses the kinetic energy of an electrochemical gradient created by primary active transport to move substances across a membrane.

Sodium-Potassium Pump

A primary active transport electrogenic pump ($\text{Na}^+/\text{K}^+$ ATPase) that exports three sodium ions and imports two potassium ions per ATP molecule hydrolyzed.

Endocytosis

A type of active transport that moves large particles, fluid, or cells into a cell by forming a pocket in the plasma membrane that pinches off as an intracellular vesicle.