Chapter 3 & 3.4 The Cell - Vocabulary Flashcards

Vocabulary flashcards covering major concepts from the lecture notes on spontaneous generation, cell theory, prokaryotes, eukaryotes, cell structures, and related topics.

Spontaneous generation

The organic formation of life from nonliving matter; an early belief later disproved in experiments on meat/ maggots and microbes.

Abiogenesis

Another term for spontaneous generation; life arising from nonliving matter.

Pneuma

Aristotle’s concept of vital heat or life force associated with the origin of life.

Omne vivum ex vivo

Latin for 'life only comes from life'; a slogan used against spontaneous generation.

Leeuwenhoek

Pioneer microscopist who first observed microbes in 1687.

Hooke

Scientist who described cork cells and contributed to early cell theory (1665).

Modern Cell Theory

All living things are composed of cells; cells are the basic unit of life; all cells arise from pre-existing cells.

Schleiden

Co‑founder of cell theory; asserted that all parts of plants are made of cells.

Schwann

Co‑founder of cell theory; extended cells as basic units to animals and plants; discussed crystallization in cell formation.

Remak

Early observer who noted cells come from cells; contributed to cell lineage ideas; often eclipsed by Virchow.

Virchow

Proposed 'Omnis cellula e cellula' and helped establish modern cell theory and pathology.

Omnis cellula e cellula

Latin for 'every cell comes from a pre-existing cell'; core idea of modern cell theory.

Miasma theory

Idea that disease arises from foul air or polluted environments.

Germ theory of disease

Idea that disease is caused by specific microbes.

John Snow

Pioneer epidemiologist who traced cholera outbreaks to contaminated water in London.

Ignaz Semmelweis

Advocated handwashing to prevent infection transmission in clinical settings.

Joseph Lister

Introduced antiseptic surgery using carbolic acid to reduce infections.

Robert Koch

Developed methods to link specific microbes to diseases; established Koch’s postulates.

Koch’s postulates

A set of criteria to establish causation between a microbe and a disease.

Endosymbiotic theory

Theory that mitochondria and chloroplasts originated as free-living bacteria engulfed by early eukaryotes.

Endomembrane system

Interconnected membranes (ER, Golgi, lysosomes) involved in protein synthesis, modification, and trafficking.

Rough endoplasmic reticulum (RER)

ER with ribosomes; synthesizes secreted and membrane proteins.

Golgi apparatus

Organelle that processes, sorts, and packages proteins for secretion or delivery to destinations.

Lysosome

Organelle containing enzymes that digest macromolecules and waste.

Nucleus

Membrane-bound organelle containing chromatin and the nucleolus; site of genetic material.

Nucleolus

Nuclear substructure where ribosomal RNA is synthesized.

Nucleoid

Region in prokaryotes where the chromosome resides; not membrane-bound.

Cytoplasm

Cellular contents outside the nucleus; site of many metabolic activities.

Ribosome (70S vs 80S)

Ribosomes are the protein-RNA machines; prokaryotic 70S (30S + 50S) vs eukaryotic 80S (60S + 40S) subunits.

Prokaryote

Single-celled organism lacking a true nucleus; includes bacteria and archaea.

Nucleic acids

DNA and RNA; polymers of nucleotides storing and transmitting genetic information.

DNA

Deoxyribonucleic acid; double-stranded with A-T and G-C base pairs.

RNA

Ribonucleic acid; typically single-stranded with bases A, U, G, C.

Phosphodiester bond

Bond joining nucleotides between 5' phosphate and 3' hydroxyl during nucleic acid synthesis.

5' and 3' ends

Directionality of nucleic acids; synthesis proceeds 5' to 3'.

Double helix

Three-dimensional structure of DNA formed by base pairing (A-T, G-C) and sugar-phosphate backbone.

Base pairing (A-T, G-C)

Hydrogen-bonded pairing that stabilizes DNA: A with T; G with C.

Gram-positive bacteria

Bacteria with thick peptidoglycan layer; stain purple; contain teichoic acids.

Gram-negative bacteria

Bacteria with thin peptidoglycan layer and an outer membrane containing LPS; stain pink.

Peptidoglycan (murein)

Polymer forming the bacterial cell wall; thick in Gram-positive bacteria.

Teichoic acid

Polymers in Gram-positive cell walls that help anchor wall components.

Lipoteichoic acid

Teichoic acids linked to the cell membrane in Gram-positive bacteria.

Outer membrane

Additional membrane in Gram-negative bacteria containing LPS; contains porins.

Porin

Protein channels in the outer membrane that allow diffusion of small molecules.

O antigen

O-specific polysaccharide part of LPS; highly antigenic in Gram‑negative bacteria.

Lipid A

Endotoxic component of LPS that anchors LPS to the outer membrane in Gram‑negative bacteria.

S-layer

Protein/glycoprotein surface lattice that protects cells and mediates interactions.

Glycocalyx

Sugar-rich coating external to cells; includes Capsule and Slime Layer; aids adhesion and protection.

Capsule

Well-defined polysaccharide layer; virulence factor that inhibits phagocytosis.

Slime layer

Unstructured glycocalyx; aids adhesion and protection; easily removed.

Flagellum

Motility organelle; filament, hook, and basal body; rotates to propel the cell.

Pili (Sex pilus)

Fimbriae used for mating/conjugation; transfers genetic material via a pilus bridge.

Fimbriae

Short, hair-like structures that mediate adhesion to surfaces.

Endospore

Dormant, highly resistant cell form that survives extreme conditions.

Sporulation

Process by which a bacterium forms an endospore.

Germination

Return of a spore to a vegetative, growing cell.

Inclusion bodies

Stored materials within bacteria (glycogen, sulfur, magnetosomes, etc.).

Magnetosomes

Magnetic inclusion bodies used for orientation in some bacteria.

16S rRNA variable regions

Hypervariable regions (V1–V9) used for bacterial identification; conserved regions flank them.

Endomembrane system

Interconnected membranes (ER, Golgi, lysosomes) for protein processing and trafficking.

Rough ER (RER)

ER studded with ribosomes; synthesizes secreted and membrane proteins.

Smooth ER (SER)

ER lacking ribosomes; site of lipid synthesis and detoxification.

Golgi apparatus

Stacks of flattened membrane-bound sacs that modify, sort, and package proteins.

Lysosome

Organelle containing hydrolytic enzymes for digestion and waste processing.

Mitochondrion

Powerhouse of the cell; ATP production; contains own DNA and ribosomes; double membrane.

Endosymbiotic theory (mitochondria & chloroplasts)

Organelles originated as engulfed bacteria that became permanent organelles.

Chloroplast

Photosynthetic organelle in plants/algae; evidence for endosymbiosis.

Nuclear envelope

Double membrane surrounding the nucleus with nuclear pores.

Nucleolus

Nuclear substructure where ribosomal RNA synthesis occurs.

Extracellular matrix

Composite of carbohydrates and proteins outside the cell that supports and communicates with cells.

Cilia vs. flagella (eukaryotic)

Cilia are short, numerous motility structures; flagella are longer and fewer; both have 9+2 microtubule arrangement in eukaryotes.

Cytoskeleton

Network of microtubules, actin filaments, and intermediate filaments providing shape, support, and movement.

Microtubules

Tubular polymers of tubulin; part of the cytoskeleton; involved in transport and cell division.

Actin filaments

Thin filaments essential for cell movement and cytokinesis; interact with myosin.

Nucleus & chromatin

Nucleus houses DNA; chromatin condenses to chromosomes; contains nucleolus and nuclear pores.

Histones

Proteins around which DNA wraps to form chromatin in eukaryotes.

Ribosome subunits (prokaryote vs eukaryote)

Prokaryotes: 70S ribosomes (30S + 50S); Eukaryotes: 80S ribosomes (60S + 40S).

Endocytosis

Process by which cells take in external material via vesicles; includes phagocytosis and pinocytosis.

Exocytosis

Process by which cells release substances via vesicles fusing with the plasma membrane.

Extracellular matrix components

Carbohydrates, glycoproteins, and proteins forming a protective and communicative layer around cells.

RER → Golgi → Secretory vesicle pathway

Secretory pathway: proteins synthesized in RER, processed in Golgi, then packaged in vesicles for secretion.

Lipids in membranes (phospholipids)

Amphipathic lipids with hydrophilic heads and hydrophobic tails forming bilayers; include cholesterol/hopene and phospholipids.

Liposomes and micelles

Lipid-based structures used to model membranes: bilayer sheets form liposomes; surfacing hydrophilic heads and hydrophobic tails form micelles.

Lipids: triglycerides vs phospholipids

Triglycerides are nonpolar and hydrophobic; phospholipids contain a polar phosphate head and nonpolar tails, enabling membranes.

Cholesterol in membranes

Sterol that modulates membrane fluidity in eukaryotes; bacteria use hopene as an alternative.

Endospore structure stages (sporulation/germination)

Sequential stages forming protective layers around DNA; allows survival and later germination.

Clostridioides difficile (C. diff.)

Gram-positive, obligate anaerobe; forms environmentally stable endospores; causes severe diarrhea.

Fecal microbiota transplant (FMT)

Transfer of stool from healthy donor to patient to restore gut microbiota balance; used for C. diff infections.

Dysbiosis

Imbalance in microbial communities associated with disease.