General Biology Lecture Notes Review

A complete set of vocabulary flashcards covering key terms and concepts from the general biology lecture notes.

Emergent properties

New characteristics that arise from the arrangement and interactions of parts as biological complexity increases, which individual component parts do not possess on their own.

Cell

The basic unit of biological organization capable of performing all activities required for life.

Gene expression

The process of converting genetic information encoded in a gene into a functional product, typically a protein, representing the central dogma of biology.

Negative feedback

A loop-based regulatory mechanism in biological systems in which the response reduces or dampens the initial stimulus, such as lowered blood glucose halting insulin secretion by the pancreas.

Natural selection

The evolutionary mechanism proposed by Charles Darwin where the natural environment selects for the propagation of beneficial inherited traits through unequal reproductive success among individuals.

Qualitative data

Scientific data recorded as descriptions, qualities, or physical characteristics rather than numerical values.

Quantitative data

Scientific data recorded as exact numerical values, counts, measurements, statistics, tables, or graphs.

Inductive reasoning

A logical process where generalized conclusions are derived from a large set of specific observations.

Deductive reasoning

A logical process that uses general premises to extrapolate and predict specific results or hypotheses.

Hypothesis

An explanation for a natural phenomenon based on observations and assumptions that leads to a testable prediction.

Controlled experiment

An experimental design that compares an experimental group, in which an independent variable is manipulated, against a control group that receives no treatment.

Theory

A broad, well-substantiated scientific explanation of natural phenomena that is supported by a large body of evidence and generates numerous testable hypotheses.

Atomic number

The number of protons contained within the nucleus of an atom, which uniquely identifies a chemical element.

Mass number

The total sum of protons plus neutrons contained within the nucleus of an atom.

Isotopes

Atomic forms of the same chemical element that have equal numbers of protons but differ in their number of neutrons.

Valence electrons

Electrons located in an atom's outermost electron shell that dictate its highest energy state and chemical reactivity.

Covalent bond

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

Nonpolar covalent bond

A type of covalent bond formed between two atoms with similar electronegativity, resulting in equal sharing of valence electrons.

Polar covalent bond

A covalent bond between atoms that differ significantly in electronegativity, causing unequal sharing of electrons and creating partial positive and partial negative charges.

Ionic bond

A chemical bond formed by the electrostatic attraction between a oppositely charged cation and anion following electron transfer.

Hydrogen bond

A weak chemical bond formed between a hydrogen atom bearing a partial positive charge and an electronegative atom bearing a partial negative charge.

Cohesion

The phenomenon of like molecules clinging to one another, such as water molecules sticking together via hydrogen bonding to produce surface tension.

Adhesion

The clinging of one substance to a different substance, such as water molecules adhering to plant cell walls to resist gravity.

Specific heat

The amount of heat that must be absorbed or lost for $1\,g$ of a substance to change its temperature by $1\,^\circ\text{C}$.

Heat of vaporization

The quantity of heat energy a liquid must absorb for $1\,g$ of it to be converted from a liquid to a gas state.

Buffers

Substances that resist changes in pH by accepting hydrogen ions $\text{H}^+$ when excess acid is present and donating them when depleted.

Miller-Urey Experiment

A classic $1950\text{s}$ experiment that simulated early Earth atmospheric and ocean conditions to demonstrate the nonliving synthesis of organic compounds from inorganic precursors.

Hydrocarbons

Organic compounds consisting exclusively of hydrogen and carbon atoms, such as the nonpolar tails of fat molecules.

Isomers

Compounds that possess identical molecular formulas but differ in their structural arrangements, spatial orientations, or chemical properties.

Structural isomers

Isomers that differ in the covalent arrangement of their carbon atoms.

Cis-trans isomers

Isomers with identical covalent bonds that differ in spatial orientation around an inflexible double bond.

Enantiomers

Isomers that are non-superimposable mirror images of each other.

Functional groups

Specific configurations of atoms attached to carbon skeletons that participate directly in chemical reactions and confer specific properties to organic molecules.

Dehydration synthesis

A chemical reaction that covalently bonds two monomers together accompanied by the removal of a water molecule.

Hydrolysis

A chemical mechanism that breaks polymers into individual monomers through the chemical addition of a water molecule.

Glycosidic linkage

A covalent bond formed between two monosaccharides through a dehydration synthesis reaction.

Saturated fatty acid

A fatty acid with a hydrocarbon chain containing no double bonds, allowing maximum hydrogen atom saturation and dense packing into solids at room temperature.

Unsaturated fatty acid

A fatty acid containing one or more double bonds in its hydrocarbon chain, which creates kinks that prevent dense packing, causing it to remain liquid at room temperature.

Phospholipid

An amphipathic lipid made of a glycerol attached to two fatty acid tails and a charged phosphate head group, forming the fundamental structure of cell membranes.

Primary structure

The unique, linear sequence of amino acids linked by peptide bonds in a polypeptide chain.

Secondary structure

The localized coiling or folding of a polypeptide backbone into structures like $\alpha$ helices or $\beta$ pleated sheets due to hydrogen bonding.

Tertiary structure

The overall three-dimensional shape of a single polypeptide chain determined by interactions among variable R group side chains.

Quaternary structure

The overall structural protein organization resulting from the aggregation of two or more individual polypeptide subunits.

Denaturation

A process in which environmental factors like extreme temperature, pH changes, or chemicals cause a protein to unravel and lose its native shape and biological function.

Phosphodiester linkage

The covalent bond connecting adjacent nucleotides between the sugar of one and the phosphate of another to form the backbone of DNA and RNA.

Fluid mosaic model

A model describing the cell membrane as a fluid structure composed of a phospholipid bilayer with a diverse mosaic of embedded and attached proteins.

Integral proteins

Membrane proteins embedded within the hydrophobic core of the phospholipid bilayer, including transmembrane proteins that extend all the way across.

Peripheral proteins

Membrane proteins loosely bound to the surface of the lipid bilayer or to integral proteins.

Diffusion

The passive movement of molecules down their concentration gradient from an area of higher concentration to lower concentration without energy expenditure.

Osmosis

The passive movement of free water molecules across a selectively permeable membrane from a solution of lower solute concentration to one of higher solute concentration.

Tonicity

The ability of a surrounding solution to cause a cell to gain or lose water by osmosis.

Hypotonic solution

A solution with a lower solute concentration than the inside of a cell, causing water to rush in and making the cell swell or burst.

Hypertonic solution

A solution with a higher solute concentration than the inside of a cell, causing water to leave the cell and causing it to shrink or shrivel.

Isotonic solution

A solution whose solute concentration is equal to that inside a cell, producing no net water movement across the plasma membrane.

Plasmolysis

A phenomenon in plant cells placed in a hypertonic environment where water loss causes the cell membrane to pull away from the rigid cell wall.

Facilitated diffusion

The passive transport of polar or charged molecules across a biological membrane through specialized channel or carrier transport proteins.

Active transport

The movement of solutes across a cellular membrane against their concentration gradient, requiring energy input from ATP and specialized carrier proteins.

Cotransport

A transport mechanism where the passive downhill diffusion of one solute is coupled to drive the active uphill transport of another solute across a membrane.

Exocytosis

The active export of cellular substances out of a cell through the fusion of membrane-bound vesicles with the plasma membrane.

Endocytosis

The active uptake of extracellular substances into a cell through the inward budding of the plasma membrane to form new vesicles.

Phagocytosis

A type of endocytosis commonly called cellular eating, where a cell engulfs large particles or whole cells into a food vacuole.

Pinocytosis

A form of endocytosis commonly called cellular drinking, where extracellular fluid and dissolved solutes are non-specifically taken up into small vesicles.

Receptor-mediated endocytosis

A highly specific form of endocytosis triggered when specific extracellular ligands bind to cell-surface receptor proteins.

Nucleoid

The non-membrane-enclosed region in a prokaryotic cell where its circular bacterial chromosome is concentrated.

Cytosol

The semifluid, gel-like liquid fraction of the cytoplasm in which cellular organelles and components are suspended.

Nuclear envelope

A double membrane perforated by nuclear pore complexes that encloses the nucleus and regulates molecular trafficking with the cytoplasm.

Nucleolus

A dense structure within the nucleus responsible for synthesized ribosomal RNA (rRNA) and assembling ribosome subunits.

Ribosomes

Cellular complexes built from ribosomal RNA and proteins that serve as the site of cellular protein synthesis.

Smooth ER

The portion of the endoplasmic reticulum lacking ribosomes that synthesizes lipids, metabolizes carbohydrates, stores calcium ions, and detoxifies drugs and poisons.

Rough ER

The portion of the endoplasmic reticulum studded with external ribosomes that synthesizes secretory and membrane proteins.

Golgi apparatus

An organelle made of stacked membranous sacs (cisternae) that receives, modifies, sorts, and packages proteins and lipids from the ER for distribution.

Lysosome

A membrane-enclosed organelle containing hydrolytic enzymes used to digest food particles, foreign substances, and damaged organelles.

Endosymbiont theory

The evolutionary theory stating that mitochondria and chloroplasts originated as free-living prokaryotic cells that were engulfed by an ancestral eukaryotic host cell.

Peroxisome

A single-membrane metabolic organelle that transfers hydrogen to oxygen producing hydrogen peroxide, which is subsequently converted to water by catalase.

Microtubules

Hollow rods formed from tubulin proteins that give cell shape, guide organelle movements, make up cilia and flagella, and separate chromosomes in cell division.

Microfilaments

Solid rods composed of actin proteins that support cell shape and drive cell motility and muscle contraction.

Plasmodesmata

Membrane-lined channels penetrating plant cell walls that connect the cytoplasm of adjacent cells to allow exchange of water and small solutes.

Animal cell junctions

Intercellular structures in animal tissues that facilitate adhesion and communication, consisting of tight junctions (leak prevention), desmosomes (anchoring fasteners), and gap junctions (communicating channels).