EOC Biology Quick Review Vocabulary

Vocabulary flashcards summarizing major biological concepts, structures, processes, and evolutionary principles from the EOC Biology Quick Review notes.

Prokaryotic Cell

Small, simple cell lacking a nucleus and membrane-bound organelles; all bacteria are prokaryotes.

Eukaryotic Cell

Larger, complex cell containing a nucleus and numerous membrane-bound organelles.

Nucleus

Membrane-bound organelle that houses DNA and controls cellular activities.

Nucleolus

Dense region inside the nucleus where ribosome subunits are assembled.

Rough Endoplasmic Reticulum

ER studded with ribosomes; site of membrane and secretory protein synthesis.

Smooth Endoplasmic Reticulum

ER lacking ribosomes; synthesizes lipids and detoxifies drugs.

Golgi Apparatus

Stacks of membranes that modify, package, and ship proteins and lipids.

Lysosome

Vesicle containing hydrolytic enzymes for intracellular digestion and recycling.

Mitochondrion

Organelle that performs cellular respiration and produces most cellular ATP.

Nuclear Membrane

Double membrane surrounding the nucleus; regulates material flow in and out.

Ribosome

RNA-protein complex that builds polypeptides from mRNA instructions.

Flagellum

Long whip-like appendage used for locomotion in some cells, especially bacteria and sperm.

Pili

Short protein appendages on bacteria used for attachment or DNA transfer.

Vacuole

Membranous sac for storage of water, food, wastes; large central one in plants.

Chloroplast

Plant organelle where photosynthesis converts light energy to glucose.

Cell Wall

Rigid outer layer in plants, fungi, and bacteria that provides support and protection.

Passive Transport

Movement of substances across membranes without energy input, driven by concentration gradients.

Diffusion

Net movement of molecules from high to low concentration.

Facilitated Diffusion

Passive transport in which membrane proteins help specific molecules cross the membrane.

Osmosis

Diffusion of water across a semipermeable membrane.

Bulk Flow

Mass movement of fluids due to pressure or solute differences.

Active Transport

Energy-requiring movement of substances against their concentration gradient via membrane pumps or vesicles.

Membrane Pump

Carrier protein that uses ATP to move molecules across membranes, often against gradient.

Endocytosis

Active transport process that brings materials into a cell via vesicle formation.

Phagocytosis

Type of endocytosis where a cell engulfs large solid particles (‘cell eating’).

Pinocytosis

Type of endocytosis where a cell takes in extracellular fluid (‘cell drinking’).

Photosynthesis

Process in chloroplasts that converts 6 CO₂ + 6 H₂O into C₆H₁₂O₆ + 6 O₂ using light energy.

Light-Dependent Reactions

First stage of photosynthesis; light energy splits water, releasing O₂ and energizing electrons.

Calvin-Benson Cycle

Light-independent reactions that use ATP and NADPH to fix CO₂ into glucose.

Cellular Respiration

Metabolic pathway that breaks down glucose to produce ATP; includes glycolysis, Krebs cycle, and ETC.

Glycolysis

Anaerobic breakdown of glucose to pyruvate in cytoplasm; yields net 2 ATP.

Krebs Cycle

Aerobic pathway in mitochondria that oxidizes acetyl-CoA, producing CO₂, ATP, NADH, and FADH₂.

Electron Transport Chain

Series of mitochondrial membrane proteins that use electrons to create ATP via oxidative phosphorylation.

Cell Cycle

Ordered sequence of events in cell growth and division: G₁, S, G₂, M, C.

G₁ Phase

Period of cell growth and organelle production before DNA synthesis.

S Phase

Stage of DNA replication where chromosomes duplicate.

G₂ Phase

Preparation phase where cell synthesizes proteins and organelles for mitosis.

Mitosis

Division of a eukaryotic nucleus into two genetically identical nuclei.

Cytokinesis

Division of cytoplasm, resulting in two daughter cells.

Virus

Non-living infectious particle composed of DNA/RNA and a protein coat; requires host to replicate.

Vaccine

Weakened or mimic pathogen that stimulates immune system to produce protective antibodies.

Prophase

First mitotic stage; chromosomes condense and spindle forms as nuclear envelope breaks down.

Metaphase

Mitotic stage where duplicated chromosomes align at cell equator.

Anaphase

Stage where sister chromatids separate and move toward opposite poles.

Telophase

Final mitotic stage; nuclear envelopes reform and chromosomes decondense.

Cell Differentiation

Process by which unspecialized cells become specialized in structure and function.

Epigenetics

Study of heritable changes in gene expression not involving changes to DNA sequence.

Cancer Cell

Cell that has lost growth control, often exhibiting rapid division and abnormal morphology.

Nucleotide

Monomer of nucleic acids consisting of a phosphate, sugar, and nitrogenous base.

DNA Double Helix

Two antiparallel nucleotide strands twisted into a ladder-like structure held by base pairing.

Genetic Code

Set of three-base codons in mRNA that specify amino acids in protein synthesis.

Chromatin Remodeling

Epigenetic process that alters chromatin structure to regulate gene accessibility.

Transcription Control

Regulation of gene expression at the level of mRNA synthesis initiation.

Post-Transcriptional Control

Regulation of mRNA processing, splicing, transport, or stability.

Translational Control

Regulation of the rate or initiation of protein synthesis from mRNA.

Mutation

Permanent change in DNA sequence caused by replication errors or environmental factors.

Gene

Segment of DNA that codes for a specific polypeptide or RNA molecule.

Allele

Different form of a gene found at the same locus on homologous chromosomes.

Chromosome

DNA-protein structure carrying genetic information; visible during cell division.

Genotype

Genetic makeup or allele combination of an organism.

Phenotype

Observable traits expressed by an organism’s genotype.

Homologous Chromosomes

Pair of chromosomes with same genes in same order but possibly different alleles.

Homozygote

Individual with identical alleles for a given gene (e.g., AA or aa).

Heterozygote

Individual with two different alleles for a gene (e.g., Aa).

Crossing Over

Exchange of genetic material between homologous chromatids during meiosis I; increases variation.

Sex Chromosomes

Chromosomes (X and Y in humans) that determine sex and carry sex-linked genes.

Autosome

Any chromosome not involved in sex determination.

Law of Segregation

Mendelian principle stating that two alleles for each gene separate during gamete formation.

Law of Independent Assortment

Alleles of different genes assort independently into gametes if on different chromosomes.

Incomplete Dominance

Inheritance pattern where heterozygote shows intermediate phenotype between two homozygotes.

Codominance

Inheritance pattern where both alleles in heterozygote are fully expressed (e.g., AB blood type).

Sex-Linked Trait

Trait determined by gene located on a sex chromosome; often shows male bias.

Meiosis

Two-stage cell division producing four genetically varied haploid gametes from one diploid cell.

Tetrad

Pair of homologous chromosomes (four chromatids) aligned during prophase I of meiosis.

Independent Assortment (Meiosis)

Random orientation of homologous pairs during metaphase I, producing varied gametes.

Polymerase Chain Reaction (PCR)

Technique that amplifies specific DNA segments exponentially in vitro.

Stem Cell

Undifferentiated cell capable of self-renewal and giving rise to specialized cell types.

Artificial Selection

Human-directed breeding to enhance desired traits in plants or animals.

Biogeography

Study of species distribution across geographic areas as evidence of evolution.

Fossil Record

Chronological collection of preserved remains providing evidence of past life and evolutionary change.

Homologous Structures

Anatomically similar body parts in different species inherited from a common ancestor.

Vestigial Structure

Remnant of a structure that had a function in an ancestor but is reduced or unused now.

Adaptation

Inherited characteristic that increases an organism’s fitness in a specific environment.

Embryology

Study of embryos; similarities in early development indicate evolutionary relationships.

Natural Selection

Process where heritable traits that improve survival or reproduction become more common in populations.

Directional Selection

Natural selection that favors one extreme phenotype, shifting population traits in one direction.

Stabilizing Selection

Selection that favors intermediate phenotypes and reduces variation.

Disruptive Selection

Selection favoring both extremes of a trait, potentially leading to speciation.

Speciation

Formation of new species when populations become reproductively isolated.

Allopatric Speciation

Speciation that occurs after geographic separation of populations.

Sympatric Speciation

Speciation within the same geographic area, often via genetic changes or polyploidy.

Convergent Evolution

Independent evolution of similar traits in unrelated lineages due to similar selective pressures.

Divergent Evolution

Accumulation of differences leading to formation of new species from a common ancestor.

Coevolution

Reciprocal evolutionary change between interacting species, such as predator-prey or plant-pollinator.

Reproductive Isolating Mechanism

Biological barrier that prevents interbreeding between different species.

Endosymbiosis

Theory that mitochondria and chloroplasts originated from engulfed prokaryotes living symbiotically.

Taxonomy

Science of classifying organisms into hierarchical groups based on shared characteristics.

Binomial Nomenclature

Two-word Latin naming system using genus and species (e.g., Homo sapiens).

Dichotomous Key

Tool with paired statements used to identify organisms through successive choices.

Carbohydrate

Organic macromolecule used for energy and structure; includes sugars, starch, cellulose.