Introductory Microbiology – Core Vocabulary

These vocabulary flashcards cover fundamental terms, people, structures, and concepts introduced in an introductory microbiology lecture, providing a solid foundation for exam review.

Microbiology

The scientific study of microscopic organisms called microorganisms or microbes.

Pathogen

A microorganism capable of causing disease (≈3 % of all microbes).

Non-pathogen

A microorganism that does not cause disease; the majority of microbes.

Opportunistic Pathogen

A normally harmless microbe that can cause disease when it reaches the right place or the host’s defences are lowered (≈10 %).

Eukaryote

An organism whose cells possess a true membrane-bound nucleus (e.g., algae, fungi, protozoa).

Prokaryote

An organism whose cells lack a true nucleus (e.g., bacteria, archaea).

Indigenous Microflora

The collection of microbes that normally live on or in the human body, also called normal flora.

Photosynthesis (microbial)

Light-driven process by which algae and cyanobacteria produce oxygen and organic molecules.

Algae

Simple, chlorophyll-containing, non-flowering eukaryotic plants lacking true roots, stems, or leaves.

Cyanobacteria

Photosynthetic prokaryotes (blue-green algae) that release oxygen and use water in photosynthesis.

Decomposer (Saprophyte)

An organism that lives on decaying organic matter, recycling it into inorganic nutrients.

Nitrogen Cycle

Microbial conversions of atmospheric nitrogen to ammonia and nitrates and back to nitrogen gas.

Microbial Ecology

The study of relationships between microorganisms and their environments.

Bioremediation

The use of microbes to degrade or detoxify environmental pollutants such as oil spills.

Food Chain (microbial)

Sequence in which microorganisms like algae and bacteria serve as the primary food source for higher organisms.

Plankton

Tiny floating organisms (microbes and small animals) that form the base of aquatic food chains.

Phytoplankton

Photosynthetic planktonic organisms, primarily algae, that produce oxygen and biomass in oceans.

Zooplankton

Tiny aquatic animals that feed on phytoplankton.

Escherichia coli

Gram-negative, facultative anaerobic, rod-shaped bacterium living in the intestines and aiding digestion.

Biotechnology

Industrial use of microorganisms to make products such as beer, wine, enzymes, vitamins, and antibiotics.

Antibiotic

A substance produced by or derived from microorganisms that kills or inhibits other microbes.

Genetic Engineering

Insertion of foreign genes into microbes to produce useful products like insulin or growth hormone.

Cell Model (E. coli)

E. coli is a widely studied organism used to understand fundamental cellular processes.

Infectious Disease

Illness caused when a pathogen colonises the body and damages host tissues.

Microbial Intoxication

Disease resulting from ingestion of a toxin produced by microbes growing outside the body.

Microbiologist

A scientist who studies microorganisms.

Bacteriologist

A microbiologist specialising in bacteria.

Phycology

The scientific study of algae.

Protozoology

The branch of microbiology dealing with protozoa.

Mycology

The study of fungi.

Virology

The study of viruses.

Agricultural Microbiology

Field that investigates microorganisms involved in soil fertility and plant health.

Industrial Microbiology

Use of microbes in large-scale production of products; synonymous with biotechnology.

Environmental Microbiology

Study of microbes in water, soil, and air, including sewage treatment and bioremediation.

Medical Microbiology

Study of pathogens, the diseases they cause, and related immunology.

Microbial Genetics

Study of heredity and variation in microorganisms, including gene manipulation.

Microbial Physiology

Examination of microbial cell structure, metabolism, and function.

Paleomicrobiology

Investigation of ancient microorganisms from historical or fossil samples.

Parasitology

Study of parasitic protozoa, helminths, and arthropods.

Sanitary Microbiology

Microbial processes involved in waste disposal, garbage, and sewage treatment.

Veterinary Microbiology

Study of microbes that cause diseases in animals (zoonoses).

Spontaneous Generation

Discredited idea that life can arise from non-living matter (abiogenesis).

Biogenesis

Principle that living cells arise only from pre-existing living cells (proposed by Virchow).

Germ Theory of Disease

Concept that specific microbes are responsible for specific diseases.

Biological Theory of Fermentation

Idea that specific microbes produce specific fermentation products (e.g., yeast → ethanol).

Florence Nightingale

Pioneer who introduced modern nursing and sanitary practices reducing infection.

Robert Koch

Scientist who proved the germ theory and formulated Koch’s postulates.

Louis Pasteur

Microbiologist who disproved spontaneous generation, invented pasteurisation, and developed vaccines.

Ignaz Semmelweis

Physician who showed that handwashing lowers puerperal fever cases.

Antonie van Leeuwenhoek

“Father of Microbiology”; first to observe living microbes with a microscope.

Girolamo Fracastorius

16th-century scholar who described contagious disease transmission.

Zacharias Janssen

Dutch spectacle maker credited with building the early compound microscope.

John Tyndall

Physicist who developed tyndallisation, a method of intermittent boiling to destroy spores.

Joseph Lister

Surgeon who introduced antiseptic techniques in surgery.

Julius Petri

Bacteriologist who invented the Petri dish for culturing microbes.

Fanny Hesse

Microbiologist who suggested agar as a solid growth medium.

Edward Jenner

Physician who created the smallpox vaccine; “Father of Immunology.”

Cell (biology)

Fundamental living unit exhibiting all characteristics of life.

Prokaryotae (Monera)

Kingdom containing bacteria and archaea—single-celled organisms without a nucleus.

Protista

Kingdom comprising mostly unicellular algae and protozoa with nuclei.

Fungi (Kingdom)

Eukaryotic kingdom of yeasts, molds, and mushrooms with chitin cell walls.

Plantae

Kingdom of multicellular, photosynthetic organisms with cellulose cell walls.

Animalia

Kingdom of multicellular, heterotrophic organisms lacking cell walls.

Three-Domain System

Classification based on rRNA: Bacteria, Archaea, and Eukarya.

Nucleus

Membrane-bound organelle housing eukaryotic DNA.

Endoplasmic Reticulum

Eukaryotic membranous network; RER bears ribosomes, SER lacks them.

Ribosome

Organelle where proteins are synthesised; 70S in prokaryotes, 80S in eukaryotes.

Golgi Complex

Organelle that modifies, sorts, and packages proteins and lipids.

Lysosome

Membrane vesicle containing digestive enzymes for intracellular digestion.

Mitochondrion

Eukaryotic organelle that generates ATP; “powerhouse” of the cell.

Cytoskeleton

Network of protein filaments that give eukaryotic cells shape and support.

Peptidoglycan

Complex polysaccharide-peptide polymer forming bacterial cell walls.

Cell Wall (bacterial)

Rigid external layer providing shape; thick in Gram-positive, thin plus outer membrane in Gram-negative bacteria.

Flagellum

Long whip-like appendage that propels motile cells.

Peritrichous Flagella

Arrangement with flagella distributed over the entire bacterial surface.

Lophotrichous Flagella

Cluster of flagella at one or both ends of a bacterium.

Pilus (plural Pili)

Hair-like surface structure used for adhesion or DNA transfer (conjugation).

Endospore

Highly resistant, dormant structure formed by Bacillus and Clostridium species.

Gram-Positive Bacteria

Bacteria with thick peptidoglycan walls that retain crystal violet stain.

Gram-Negative Bacteria

Bacteria with thin peptidoglycan and outer membrane; stain pink with safranin.

Virus

Acellular infectious agent (10–300 nm) containing nucleic acid (DNA or RNA) within a protein coat.

Bacteriophage

Virus that infects bacteria; may follow lytic or lysogenic cycles.

Oncogenic Virus

Virus capable of causing cancer (e.g., HPV, EBV).

Prion

Infectious protein particle lacking nucleic acid; causes neurodegenerative diseases.

Viroid

Small, circular RNA molecule without a protein coat that infects plants.

Koch’s Postulates

Four criteria used to prove that a specific microbe causes a specific disease.

Binary Fission

Asexual reproduction process in which a prokaryote duplicates and divides into two identical cells.

Mitosis

Eukaryotic asexual nuclear division resulting in two identical daughter nuclei.

Meiosis

Eukaryotic cell division producing haploid gametes for sexual reproduction.