What's in Microbiology: All 18 Units of the Course

Intro microbiology is the course where biology, chemistry and medicine meet. It starts with how to see a microbe at all, works through what microbes are made of and how they grow, and finishes with how they cause disease and how the body fights back. Encodr's free Microbiology course covers all 26 chapters of OpenStax Microbiology in book order, split into 18 units, 100 chapters and 1,341 study cards from 27 sources.

Here is what each unit covers, in the order the course teaches it.

Foundations and the microbial cell (units 1-2, OpenStax ch 1-3)

Unit 1, Foundations and Microscopy (8 chapters). The history of the field, from miasma theory to van Leeuwenhoek, Pasteur and Koch. Spontaneous generation and its refutation, ending with Pasteur's swan-neck flask. Taxonomy, binomial names and the three domains. Then the tools: light, wavelength and resolution, the microscope types (brightfield, darkfield, phase-contrast, fluorescence, electron microscopes), and staining. The Gram stain and the acid-fast stain are introduced here and come back for the rest of the course.

Unit 2, The Microbial Cell (8 chapters). Cell theory and the endosymbiotic theory, cell shapes and arrangements, the prokaryotic membrane and transport, the nucleoid, plasmids and 70S ribosomes, and the cell wall: thick peptidoglycan in gram-positive bacteria versus a thin layer plus an outer membrane in gram-negatives. Also flagella, fimbriae and pili, endospores, and eukaryotic microbial cells. Gram-positive vs gram-negative bacteria goes deeper on the wall, because almost every later unit leans on it.

The microbial world (units 3-5, ch 4-6)

Unit 3, Prokaryotic Diversity (6 chapters). Where prokaryotes live and the five kinds of symbiosis, the five classes of Proteobacteria, other gram-negative groups (chlamydias, spirochetes, cyanobacteria), the gram-positive firmicutes and actinobacteria, deeply branching bacteria, and the archaea.

Unit 4, Eukaryotic Microbes (5 chapters). Protozoa (locomotion, trophozoites and cysts, named parasites like Giardia and Plasmodium), parasitic helminths, fungi (yeasts, molds, dimorphic fungi), algae, and lichens.

Unit 5, Acellular Pathogens (4 chapters). Virus structure and classification, the lytic and lysogenic cycles and animal virus replication, culturing and detecting viruses, and viroids, virusoids and prions.

These three units are the most memorization-heavy part of the first half: dozens of named organisms with defining features.

How microbes live: biochemistry, metabolism, growth and genetics (units 6-10, ch 7-12)

Unit 6, Microbial Biochemistry (4 chapters). Carbohydrates, lipids and membranes, proteins, and how labs identify microbes biochemically (FAME, MALDI-TOF, Lancefield grouping).

Unit 7, Microbial Metabolism (6 chapters, 99 cards, one of the largest). Enzymes and redox, glycolysis and its alternatives (Entner-Doudoroff, pentose phosphate), ATP yield tallies, fermentation types, photosynthesis, and the carbon, nitrogen and sulfur cycles.

Unit 8, Microbial Growth and Culture (4 chapters). Binary fission and the four-phase growth curve, biofilms and quorum sensing, the math of counting cells (CFU from serial dilutions, generation time), oxygen, pH and temperature classes, and culture media (selective, differential, and both, like MacConkey agar).

Unit 9, Microbial Genetics (8 chapters, 98 cards). DNA and RNA structure, replication, transcription and translation in prokaryotes, mutations and repair, horizontal gene transfer (transformation, transduction, conjugation), and operons such as lac and trp.

Unit 10, Applications of Microbial Genetics (5 chapters). Cloning and vectors, PCR, gel electrophoresis and sequencing, genomics, and gene therapy.

This stretch overlaps most with general biology. If you've taken it, what's in General Biology I shows which parts will feel familiar. The metabolism unit also connects to a nutrition course, which covers the same pathways from the human side; see what's in a nutrition course.

Controlling microbes (units 11-12, ch 13-14)

Unit 11, Control of Microbial Growth (4 chapters). Sterilization versus disinfection versus antisepsis, physical methods (autoclaving, pasteurization, filtration, radiation), chemical agents by class, and ways to measure effectiveness such as the phenol coefficient.

Unit 12, Antimicrobial Drugs (5 chapters). The history from Salvarsan to penicillin, selective toxicity, antibacterial drugs grouped by mechanism (cell wall, protein synthesis, nucleic acid synthesis, metabolic pathways, membranes), antifungal, antiviral and antiparasitic drugs, resistance mechanisms, and susceptibility testing (Kirby-Bauer, MIC, MBC).

Disease and immunity (units 13-17, ch 15-20)

Unit 13, Mechanisms of Pathogenicity (3 chapters). Pathogenicity versus virulence, the five periods of disease, portals of entry and exit, adhesion, and toxins: endotoxin versus exotoxins.

Unit 14, Disease and Epidemiology (4 chapters). Reservoirs and transmission, healthcare-associated infections, incidence and prevalence with rate math, outbreak patterns, and public health agencies.

Unit 15, Innate Immunity (4 chapters). Physical and chemical barriers, leukocyte types, pathogen recognition, inflammation and fever, and complement.

Unit 16, Adaptive Immunity (5 chapters). Antigens and antibodies, MHC and antigen presentation, T cells, B cells and the five antibody classes, and vaccines and the four types of immunity.

Unit 17, Immune Disorders and Testing (4 chapters). Hypersensitivity types I to IV, autoimmune disease, transplant rejection, immunodeficiency, and lab tests built on antibodies (agglutination, ELISA, precipitation, immunofluorescence).

Infectious diseases by body system (unit 18, ch 21-26)

Unit 18, Infectious Diseases by Body System (13 chapters, 143 cards), is the largest unit. It walks through skin and eye, respiratory, urogenital, digestive, circulatory and lymphatic, and nervous system infections. Each named disease carries its causative agent, how it spreads, and how it is diagnosed or treated.

The disease names here are built from medical word parts (meningitis, pyelonephritis, endocarditis). If those still look opaque, what's in Medical Terminology covers the vocabulary course that pairs with this one.

Where the math is, and where the memorizing is

Most of the course is concepts and vocabulary. The math is modest and concentrated in a few places: CFU-from-dilution and generation-time calculations (unit 8), ATP yields (unit 7), the phenol coefficient (unit 11), MIC from a twofold dilution series (unit 12), and incidence and mortality rates (unit 14). Every numeric card was recomputed before publishing.

The memorizing is heavier: named organisms in units 3 to 5, drug classes in unit 12, and the disease survey in unit 18. Comparison tables carry most of that load, and how to memorize a list, a table or a formula sheet has a method for each. Because the final units draw on everything before them, the course behaves like one long cumulative final; studying for a cumulative final vs a unit test explains how to keep early units alive.

How the course is built

Each chapter opens with a note card, then mixes short answer, multiple choice, cloze, true or false and typed calculation cards. There are no images: every stain result, structure and process is described in words. At 1,341 cards, the flashcard deck time estimator is worth a look before you set a daily pace.

How to study for Microbiology has a plan for each kind of material. Microbiology is one of several free courses on Encodr, listed in the free gen ed course flashcards roundup, and you can start with the Microbiology flashcards today.