Cell Biology, Microscopy & Prokaryotic Structure – Vocabulary Review

A comprehensive set of vocabulary flashcards covering foundational cell biology, microscopy, eukaryotic organelles, plant-specific structures, and prokaryotic anatomy for exam review.

Cell Theory

States that the cell is the basic unit of life, all living things are made of cells, and cells arise from pre-existing cells.

Modern Cell Theory

Adds that cells carry DNA, have similar chemical composition & metabolic activities, and depend on organelles for function.

Robert Hooke

1665 scientist who first observed ‘cells’ in cork; called the Father of Cytology.

Anton van Leeuwenhoek

1673 microscopist who discovered single-celled ‘animalcules’; Father of Microbiology.

Spontaneous Generation

Discredited idea that life arises from non-living matter without parents.

Jean Baptiste Lamarck

Proposed cells are fluid-filled and advanced Lamarckism (use & disuse, inheritance of acquired traits).

Francesco Redi

Demonstrated that maggots do not spontaneously generate; Father of Experimental Biology.

Lazzaro Spallanzani

Used boiled broth to disprove abiogenesis, supporting biogenesis.

Osmosis

Diffusion of a solvent through a semipermeable membrane from low to high solute concentration (Dutrochet).

Robert Brown

Discovered and named the cell nucleus (1831).

Protoplasm

Living substance inside a cell, first described by Félix Dujardin and named by Purkinje.

Matthias Schleiden

Botanist who concluded all plants are made of cells (1838).

Theodor Schwann

Physiologist who concluded all animals are made of cells (1839).

Louis Pasteur

Formulated Biogenesis, Germ Theory, and invented pasteurization.

James Watson & Francis Crick

Proposed the double-helix model of DNA (1953).

Rosalind Franklin

Generated Photo 51 X-ray image crucial to DNA structure discovery.

Maurice Wilkins

Produced first crystalline DNA patterns; shared Nobel with Watson & Crick.

Stereo Microscope

Low-power (10×–40×) microscope that gives a 3-D surface view with reflected & transmitted light.

Compound Microscope

Common laboratory microscope with multiple objective lenses (40×–1000×) for thin specimens.

Inverted Microscope

Microscope with objectives below the stage; ideal for petri-dish cultures & live-cell imaging.

Metallurgical Microscope

High-power reflected-light microscope (50×–500×) for opaque metals and coatings.

Polarizing Microscope

Uses polarizer and analyzer to view birefringent minerals and chemicals.

Transmission Electron Microscope (TEM)

Electron microscope providing ultrastructure details with very high resolution.

Scanning Electron Microscope (SEM)

Electron microscope that images surface topography and composition in high resolution.

Microscope Head (Body Tube)

Cylindrical part that connects eyepiece to objective lenses and houses light path.

Microscope Arm

Structural part connecting base to head; used to carry the microscope.

Microscope Base

Bottom support housing illuminator and power controls.

Eyepiece (Ocular Lens)

Lens nearest the eye, typically 10× or 15× magnification.

Nosepiece

Revolving turret that holds and switches objective lenses.

Objective Lens

Lens closest to specimen; primary magnifier (4×, 10×, 40×, 100×).

Fine Adjustment Knob

Moves stage slowly for sharp focus, used at high power.

Coarse Adjustment Knob

Moves stage rapidly for initial focus at low power.

Stage

Platform that holds the specimen slide; often mechanical for precise movement.

Condenser

Lens system below stage that focuses light on the specimen.

Diaphragm (Iris)

Controls amount and cone of light reaching the specimen.

Plasma Membrane

Fluid-mosaic phospholipid bilayer that defines cell boundaries and regulates transport.

Phospholipid

Amphipathic molecule forming the bilayer with hydrophilic heads and hydrophobic tails.

Cholesterol (Membrane)

Steroid that stabilizes and stiffens the plasma membrane.

Glycocalyx

External carbohydrate coat providing protection, identity tags, and cell adhesion.

Microvilli

Minute membrane extensions that vastly increase surface area for absorption.

Nucleus

Membrane-bound control center housing DNA and nucleoli.

Nuclear Envelope

Double membrane with pores surrounding the nucleus; supported by nuclear lamina.

Nucleolus

Dense nuclear region where ribosomal RNA and subunits are produced.

Rough Endoplasmic Reticulum (RER)

Flattened sacs covered in ribosomes; synthesizes proteins and membrane lipids.

Smooth Endoplasmic Reticulum (SER)

Tubular network without ribosomes; synthesizes lipids, detoxifies drugs, stores Ca²⁺.

Ribosome

RNA-protein particle that translates mRNA into polypeptides; 80S (eukaryotic) or 70S (prokaryotic).

Golgi Apparatus

Stack of cisternae that modifies, sorts, and packages proteins into vesicles.

Lysosome

Membrane vesicle containing hydrolytic enzymes for intracellular digestion and autolysis.

Peroxisome

Organelle that oxidizes molecules, breaks down H₂O₂, and detoxifies toxins.

Proteasome

Cylindrical protein complex that degrades ubiquitin-tagged proteins into peptides.

Mitochondrion

Double-membrane ‘powerhouse’ producing ATP via oxidative phosphorylation.

Endosymbiotic Theory

Proposes mitochondria evolved from engulfed aerobic bacteria; supported by mtDNA and ribosomes.

Cristae

Folded inner mitochondrial membrane that increases surface area for ATP production.

Centrioles

Paired tubulin cylinders organizing microtubules and forming spindle & basal bodies.

Cytoskeleton

Network of microfilaments, intermediate filaments, and microtubules providing support and motility.

Microfilament (Actin Filament)

Thin 7 nm filament involved in cell shape and movement.

Intermediate Filament

Stable 8–10 nm fiber that resists tension and anchors organelles.

Microtubule

Hollow 25 nm tubulin tube essential for chromosome movement and intracellular transport.

Cilium

Short hair-like projection with 9 + 2 microtubules; beats to move fluid or cell.

Flagellum (Eukaryotic)

Long whip-like motility organelle with 9 + 2 axoneme; e.g., sperm tail.

Pseudopodium

Temporary cytoplasmic extension enabling amoeboid movement and phagocytosis.

Vesicle

Small membrane sac for transport or storage within the cell.

Vacuole

Large membrane compartment for storage, turgor maintenance, or waste sequestration (plant cells).

Cell Wall (Plant)

Rigid cellulose layer external to plasma membrane providing support and shape.

Middle Lamella

Pectin-rich outer layer cementing adjacent plant cells together.

Primary Cell Wall

Thin, flexible cellulose layer formed during cell growth.

Secondary Cell Wall

Thick, lignin-reinforced layer providing extra strength after growth ceases.

Plastid

Plant organelle group for storage or photosynthesis; includes chloroplasts, chromoplasts, leucoplasts.

Chloroplast

Double-membrane plastid containing chlorophyll; site of photosynthesis.

Thylakoid

Membranous sac inside chloroplast where light reactions occur; stacked into grana.

Stroma

Fluid matrix of chloroplast containing enzymes for Calvin cycle.

Flagellum (Bacterial)

Protein filament anchored by basal body that rotates for bacterial motility.

Pilus (Fimbria)

Hair-like protein appendage mediating bacterial adhesion or DNA transfer.

Peptidoglycan

Rigid polysaccharide-peptide mesh forming bacterial cell wall; thicker in Gram-positive bacteria.

Teichoic Acid

Negatively charged polymer in Gram-positive walls; antigenic and structural.

Lipopolysaccharide (LPS)

Endotoxin in Gram-negative outer membrane composed of lipid A and O-antigen.

Plasmid

Extrachromosomal circular DNA in bacteria carrying genes such as antibiotic resistance.

Endospore

Heat-resistant, dormant structure produced by Bacillus and Clostridium for survival.

Nucleoid

Irregular region of prokaryotic cytoplasm containing chromosomal DNA.

Mesosome

Folded invagination of bacterial plasma membrane possibly involved in replication and respiration.

Capsule (Bacterial)

Thick polysaccharide layer outside the cell wall that inhibits phagocytosis.