Microbiology: Humans, Microbial World, and Cellular Structure

Flashcards testing core vocabulary, historical facts, taxonomy, and structural components from the introductory microbiology and cellular structure lectures.

Antony van Leeuwenhoek

A Dutch fabric merchant credited with the birth of microbiology in 1674 after using a simple magnifying glass to observe 'animalcules' in lake water.

Robert Hooke

An English scientist credited alongside Leeuwenhoek with the discovery of microorganisms, who described 'microscopical mushroom' (common bread mold) in 1665.

Normal Microbiota

The population of microorganisms (normal flora) covering all body surfaces that protect against pathogens by competing for resources, aiding digestion, and stimulating immune system development.

Pathogens

Microorganisms that cause disease symptoms by damaging host body tissues.

Bioremediation

The application of microorganisms to hasten the decay and degradation of environmental pollutants such as PCBs, DDT, trichloroethylene, and oil spills.

Biotechnology

The use of microbiological and biochemical techniques to solve practical real-world problems.

Genetic Engineering

The technique of introducing genes into another organism to confer new traits, such as creating disease-resistant plants or manufacturing pharmaceutical insulin.

Smallpox

A viral disease that caused approximately 10 million deaths over 4,000 years before being globally eradicated in 1977.

Plague

A bacterial disease that killed roughly 1/3 of Europe's population (~25 million people) between 1346 and 1350, now controlled via rodent population management and antibiotics.

Emerging Diseases

Infectious diseases that are newly recognized or increasing in incidence, such as Swine flu, SARS, MERS, Ebola virus disease, and Lyme disease.

Helicobacter pylori

A bacterium shown to cause peptic stomach ulcers, demonstrating that chronic conditions can have microbial origins.

Domain Bacteria

Single-celled prokaryotic organisms with rigid cell walls containing peptidoglycan, lacking membrane-bound organelles, and reproducing by binary fission.

Domain Archaea

Single-celled prokaryotes that lack peptidoglycan in their cell walls, possess unique ribosomal RNA sequences, and often live as extremophiles.

Domain Eukarya

Organisms containing eukaryotic cells with a membrane-bound nucleus and organelles, encompassing fungi, algae, protozoa, and helminths.

Binomial System of Nomenclature

The two-word taxonomic naming convention consisting of an italicized or underlined capitalized Genus and lowercase species name (e.g., Escherichia coli).

Coccus

A spherical bacterial cell shape.

Bacillus (Rod)

A cylindrical or rod-shaped bacterial cell.

Vibrio

A short, curved rod-shaped bacterial cell.

Spirillum

A curved rod shape long enough to form spirals.

Spirochete

A long, spiral-shaped bacterial cell with a flexible cell wall and specialized motility.

Pleomorphic

Refers to bacteria that naturally vary in shape rather than exhibiting a uniform morphology.

Diplococcus

Cocci that remain in pairs after dividing in a single plane, such as Neisseria gonorrhoeae.

Fungi

Diverse eukaryotic organisms ranging from single-celled yeasts to multicellular molds and mushrooms, deriving energy from degradation of organic matter.

Algae

Photosynthetic eukaryotic organisms containing chloroplasts with chlorophyll, having rigid cell walls, and inhabiting primarily aquatic environments.

Protozoa

Single-celled, complex eukaryotic organisms that lack rigid cell walls, ingest organic material, and are typically motile.

Helminths

Parasitic worms (roundworms, tapeworms, flukes) whose adult stages are usually macroscopic but possess microscopic eggs and larval stages.

Viruses

Acellular infectious agents composed of nucleic acid packaged inside a protein coat; obligate intracellular parasites inactive outside host cells.

Viroids

Acellular infectious agents simpler than viruses, consisting only of a short piece of RNA without a protein coat, which cause plant diseases.

Prions

Infectious misfolded proteins found in the brain that force normal cellular proteins to misfold, causing fatal neurodegenerative diseases.

Basic Dyes

Positively charged stains that bind to negatively charged cellular structures in simple or differential staining.

Acidic Dyes

Negatively charged stains used in negative staining, repelled by cells to color the background.

Gram Stain

A differential staining procedure developed by Hans Christian Joachim Gram that classifies bacteria into Gram-positive (purple) and Gram-negative (pink) based on cell wall composition.

Fluid Mosaic Model

Model describing the cytoplasmic membrane structure, wherein proteins drift dynamic within a fluid phospholipid bilayer.

Aquaporins

Membrane-spanning proteins that facilitate the rapid passage of water molecules across the cytoplasmic membrane.

Facilitated Diffusion

Form of passive transport using carrier proteins to move molecules down their concentration gradient without expending energy.

Active Transport

Energy-requiring transport mechanism moving substances against a concentration gradient using proton motive force or ATP (ABC transporters).

Group Translocation

A transport process in prokaryotes that chemically modifies a compound (such as phosphorylating glucose) as it crosses the membrane.

Signal Sequence

An amino acid tag on a preprotein that targets it for secretion across the cytoplasmic membrane.

Peptidoglycan

A rigid cell wall polymer unique to bacteria, composed of alternating NAG and NAM glycan chains cross-linked by tetrapeptide chains.

Teichoic Acids

Negatively charged chains bound to peptidoglycan or the membrane in Gram-positive bacterial cell walls.

Lipopolysaccharide (LPS)

Component of the Gram-negative outer membrane containing Lipid A and O antigen, acting as an endotoxin that triggers host immune responses.

Periplasm

A gel-like material rich in proteins filling the periplasmic space between the inner membrane and outer membrane of Gram-negative bacteria.

Penicillin

An antibiotic that targets peptidoglycan by interfering with the cross-linking of adjacent glycan chains, leading to cell lysis.

Lysozyme

An enzyme present in tears and saliva that degrades peptidoglycan by breaking the covalent bonds connecting NAG and NAM subunits.

Capsule

A distinct, organized gelatinous layer outside the cell wall that facilitates attachment and helps pathogens evade innate immune defenses.

Slime Layer

A diffuse, irregular outer layer enabling bacteria to adhere to environmental surfaces.

Biofilm

A community of microbes embedded within an extracellular polysaccharide matrix attached to a surface (e.g., dental plaque).

Flagella

Long, helical protein structures made of flagellin that rotate like propellers to grant bacterial motility.

Chemotaxis

Directed movement of bacteria toward attractants (nutrients) or away from repellents (toxins) through coordinated runs and tumbles.

Pili (Fimbriae)

Short surface appendages on bacteria used for attachment, twitching/gliding motility, or conjugation (sex pilus).

Nucleoid

The nuclear region in a prokaryotic cell that contains the single, circular double-stranded DNA chromosome without a surrounding membrane.

Plasmids

Small, circular, extrachromosomal double-stranded DNA molecules carrying non-essential genes (such as antibiotic resistance) that can transfer between cells.

70S Ribosome

Prokaryotic ribosome composed of 30S and 50S subunits, serving as the site of protein synthesis and target for specific antibiotics.

80S Ribosome

Eukaryotic ribosome found in the cytoplasm, composed of 40S and 60S subunits.

Endospores

Extremely durable, dormant cells produced by Bacillus and Clostridium species that survive extreme heat, desiccation, chemical exposure, and UV radiation.

Endosymbiotic Theory

Theory stating that eukaryotic mitochondria and chloroplasts originated from ancestral prokaryotes living endosymbiotically inside larger host cells.

Golgi Apparatus

Eukaryotic organelle formed of flattened membrane sacs that modifies, sorts, and packages macromolecules synthesized in the endoplasmic reticulum.

Lysosomes

Eukaryotic membrane-bound organelles containing digestive enzymes that degrade endocytosed materials and old cellular components (autophagy).

Peroxisomes

Organelles in eukaryotic cells that utilize oxygen to break down lipids and toxic chemicals, safely generating and degrading hydrogen peroxide.