Microbiology Lecture Notes - VOCABULARY Flashcards

Vocabulary flashcards covering key terms and definitions from the lecture notes on microorganism classification, cell structure, metabolism, and basic microbiology concepts.

Prokaryote

Organism lacking a true nucleus and membrane-bound organelles; nucleoid region instead.

Eukaryote

Organism with a true nucleus and membrane-bound organelles.

Bacteria

Prokaryotic domain with cell walls typically made of peptidoglycan.

Archaea

Prokaryotic domain with unique cell wall polymers (not peptidoglycan), often in extreme environments.

Fungi

Eukaryotic organisms with a membrane-bound nucleus; obtain food from other organisms; have cell walls.

Protozoa

Single-celled eukaryotes; animal-like nutrient needs; locomotion via pseudopods, cilia, or flagella.

Algae

Unicellular or multicellular photosynthetic eukaryotes.

Viruses

Acellular obligate intracellular parasites that require a host; host-specific.

Prions

Infectious proteins lacking nucleic acids.

Antoni van Leeuwenhoek

Late 17th-century pioneer who made simple microscopes and observed microorganisms.

Koch’s Postulates

Four steps to link a microbe to a disease: found in diseased hosts, isolated, causes disease in healthy hosts, re-isolated from experimental disease.

Gram-positive bacteria

Bacteria with a thick peptidoglycan layer; stain purple; may have teichoic/lipoteichoic acids.

Gram-negative bacteria

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

Teichoic acids

Polymers in Gram-positive cell walls associated with teichoic/lipoteichoic acids.

Lipoteichoic acids

Teichoic acids anchored in the cytoplasmic membrane of Gram-positive bacteria.

Lipopolysaccharide (LPS)

Outer membrane component of Gram-negative bacteria; lipid A can trigger fever and shock.

Mycolic acid

Long-chain fatty acids in some bacteria (e.g., Mycobacterium) aiding environmental survival (acid-fast).

Mycoplasma

Bacteria lacking a cell wall.

Glycocalyx

外 glycocalyx: external layer; capsule (organized) or slime layer (loose); aids in attachment and immune evasion.

Capsule

Organized, firmly attached glycocalyx; helps evade host defenses.

Slime layer

Loose, water-soluble glycocalyx; aids in attachment.

Flagella

Structure responsible for bacterial motility; consists of filament, hook, basal body.

Fimbriae

Sticky, hairlike projections for adherence; shorter than flagella.

Pili (conjugation pili)

Longer than fimbriae; transfer DNA between cells during conjugation.

Conjugation

DNA transfer between bacterial cells via a pilus.

Endospore

Defensive, dormant structure enabling survival under harsh conditions.

Ribosome 70S

Prokaryotic ribosome (30S + 50S subunits) site of protein synthesis.

Ribosome 80S

Eukaryotic ribosome (40S + 60S subunits) site of protein synthesis.

Cytoplasmic membrane

Phospholipid bilayer surrounding cytoplasm; controls transport and energy processes in some bacteria.

Glycocalyces and biofilms

Glycocalyces aid biofilm formation and adherence of cells to surfaces.

Endocytosis

Process of taking substances into the cell via vesicles; includes phagocytosis and pinocytosis.

Phagocytosis

Endocytosis of solid particles by cells.

Pinocytosis

Endocytosis of liquids by cells.

Lysosome

Organelle containing enzymes; involved in digestion within the cell.

Mitochondria

Organelles with double membrane; produce most ATP; contain 70S ribosomes and circular DNA.

Chloroplasts

Organelles in plants/algae for photosynthesis; contain 70S ribosomes.

Endosymbiotic theory

Idea that eukaryotes evolved from symbiotic relationships with bacteria (mitochondria/chloroplasts derived from bacteria).

Cyanobacteria

Photosynthetic prokaryotes; ancestors of chloroplasts.

Glycolysis

Metabolic pathway: glucose (C6) to 2 pyruvate (C3) in cytoplasm; net 2 ATP and 2 NADH; substrate-level phosphorylation.

Krebs (Citric Acid) Cycle

Cyclic pathway converting acetyl-CoA to CO2; produces ATP, NADH, FADH2.

Electron Transport Chain (ETC)

Series of carriers transferring electrons; creates proton gradient for oxidative phosphorylation.

Oxidative phosphorylation

ATP synthesis driven by the proton gradient across the membrane via ATP synthase.

Substrate-level phosphorylation

Direct transfer of a phosphate from a substrate to ADP to form ATP.

Fermentation

Anaerobic process that regenerates NAD+ for glycolysis by converting pyruvate to lactate or ethanol; does not use ETC.

NAD+/NADH

Nicotinamide adenine dinucleotide; NAD+ accepts electrons to become NADH; key redox carrier.

NADP+/NADPH

Nicotinamide adenine dinucleotide phosphate; NADP+ accepts electrons to NADPH; used in biosynthesis.

FAD/FADH2

Flavin adenine dinucleotide; electron carrier that becomes FADH2.

Coenzyme

Non-protein organic molecule that assists enzyme activity; many are cofactors or coenzymes.

Amino acids

21 building blocks of proteins; linked by peptide bonds.

Peptide bond

Covalent bond linking neighboring amino acids in a protein.

Polypeptide

A chain of amino acids forming a protein.

Amino acid side chain (R-group)

Variable group determining protein structure and interactions.

Nucleotides

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

Nucleosides

Nucleotides lacking the phosphate group.

Nucleic acids

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

A-T and G-C hydrogen bonds

DNA base-pairing: A pairs with T via two hydrogen bonds; G pairs with C via three hydrogen bonds.

ATP

Adenosine triphosphate; main short-term energy currency of cells.

Carbohydrates

Macromolecules of C, H, O; monosaccharides, disaccharides, polysaccharides; roles in energy and structural components.

Monosaccharides

Simple sugars; basic building blocks of carbohydrates.

Disaccharides

Two monosaccharides linked together.

Polysaccharides

Many monosaccharides linked; examples include storage and structural polysaccharides.

Lipids

Hydrophobic macromolecules; four groups: fats (triglycerides), phospholipids, waxes, steroids.

Triglycerides

Fats composed of glycerol and three fatty acids; major lipid in blood.

Phospholipids

Lipids forming the lipid bilayer of cell membranes with hydrophilic heads and hydrophobic tails.

Waxes

Hydrophobic lipids with protective functions.

Steroids

Lipids with four fused carbon rings.

Cell wall (bacteria)

Rigid structure that provides shape and protection; made of peptidoglycan in many bacteria.

Glycocalyx in biofilms

External layer aiding adherence and biofilm formation.

Prokaryotic cell shapes/arrangements

Arrangements result from planes of division and separation (e.g., bacillus, staph-like arrangements).

Pleomorphism

Ability of some bacteria to alter shape or size in response to environmental conditions.

Endospores vs vegetative cells

Endospores are dormant, resistant forms; vegetative cells are metabolically active.

Cell membrane transport types

Passive (diffusion, facilitated diffusion, osmosis) and active (active transport, group translocation).

Osmosis and tonicity

Movement of water across membranes; tonicity describes solute concentration relative to the cell (hypertonic, hypotonic, isotonic).

Endocytosis vs exocytosis

Endocytosis brings materials in; exocytosis releases materials from the cell.

Cilia

Short, hairlike structures used for movement in some protozoa.

Pseudopods

Cellular extensions used by some protozoa for movement and food capture.

Flagella (organisms)

Structure used for motility; varies in composition between bacteria and eukaryotes.

Mitochondrial ribosomes

Mitochondria have 70S ribosomes and circular DNA, similar to bacteria.

Chloroplast ribosomes

Chloroplasts have 70S ribosomes, similar to bacteria.

Endosymbiosis in eukaryotes

Origin of mitochondria and chloroplasts from ancient endosymbiotic bacteria.

Cell walls in eukaryotes

Fungi, algae, plants have cell walls with varying compositions (cellulose, chitin, glucomannan).

Photosynthesis in algae

Algae are photosynthetic, contributing to primary production in aquatic environments.

Acellular agents

Viruses are acellular, lacking cytoplasmic membranes and cellular structure.

Biofilm

A structured community of microbes adhering to surfaces, embedded in a self-produced matrix.