Web Microbiology at ACM

Chapter 8, Episode 14 This episode introduces the foundational tools used to study and manipulate DNA, including restriction enzymes, PCR, and cloning vectors. You’ll learn how DNA can be cut at specific sequences, amplified into millions of copies, and transferred between organisms for genetic analysis and engineering. These techniques are essential for understanding how scientists work with gene...

Chapter 6, Episode 13 This episode explains how mutations alter DNA sequences, including point mutations, insertions, deletions, and frameshifts, and how these changes can affect protein function and phenotype. It also discusses mutagens, DNA repair mechanisms, and the biological significance of mutation in genetics, disease, and microbiology.

Chapter 6, Episode 12 This episode discusses the unique ways bacteria evolve through DNA. They transfer genetic material horizontally, within the same generation, and the processes by which this is accomplished are discussed in the episode.

Chapter 6, Episode 11 This episode introduces the operon, and discusses how bacterial cells control gene expression. The lac operon is discussed in detail as an example of the ways bacteria conserve energy and only make proteins when they are necessary for survival.

Chapter 6, Episode 10 This episode is a continuation of the central dogma, focusing on the process of translation and how ribosomes create proteins from messenger RNA.

Chapter 6, Episode 9 This episode introduces the central dogma and the genetic code. We'll discuss how cells create protein from genes, and point out the differences in the process of transcription between eukaryotic and prokaryotic cells.

Chapter 6, Episode 8 In this episode we'll discuss the process of DNA replication and point out the subtle differences between linear chromosomes and circular chromosomes and how they are replicated. We'll also cover the important enzymes involved in this process, and how proofreading prevents mutations.

Chapter 6, Episode 7 In this episode, we'll review the DNA molecule in detail, talk about how chromosomes are organized in prokaryotic and eukaryotic cells, and discuss how this organization sets cells up for replication.

Chapter 5, Episode 6 In this episode we finish the chapter on eukaryotes by discussing algae, protozoa and helminths. We review the life cycle of Plasmodium , the protozoa that causes malaria, and cover the different classifications of helminths.

Chapter 5, Episode 5 In this episode we explore the characteristics of microorganisms belonging to the kingdom of fungi. What makes them unique, what their morphologies are, the similarities between fungal cells and human cells, and the differences between fungal cells and bacteria. We also briefly touch on mycoses, the fungal pathogens, and end the episode with the benefits of fungi to humans and...

Chapter 5, Episode 4 This episode introduces the Endosymbiotic Theory and explains how complex eukaryotic cells evolved from prokaryotic ancestors. We briefly review the major groups of microbial eukaryotes and highlight the structural features, including mitochondria, chloroplasts, and membrane-bound organelles, that distinguish them from bacteria and influence how we treat eukaryotic pathogens.

Chapter 4, Episode 3 This episode examines the internal structures of bacteria, including chromosomes, plasmids, ribosomes, and the powerful survival strategy of endospore formation. We also compare bacteria to archaea and introduce Bergey’s Manual as a tool for microbial identification in clinical and lab settings.

Chapter 4, Episode 2 We dive into the external structures that help bacteria move, attach, exchange genes, and survive. From flagella and chemotaxis to pili, capsules, and the Gram-positive vs. Gram-negative cell envelope, this episode connects structure to staining, antibiotic susceptibility, and disease severity. 

Chapter 4, Episode 1 This episode explores the structure and “lifestyle” of bacterial cells, from shape and arrangement to biofilm formation and motility. Learn how features like capsules, flagella, and quorum sensing influence infection, antibiotic resistance, and clinical outcomes.

Chapter 25, Episode 16 This episode focuses on applied microbiology, water safety, and the One Health concept connecting environmental, animal, and human health. Topics include biotechnology, fermentation, wastewater treatment, waterborne pathogens, and indicator organisms. The episode also discusses spillover events, climate change, vector-borne disease, and how environmental changes can influenc...

Chapter 25, Episode 15 This episode introduces microbial ecology and explains how microorganisms are essential for maintaining life on Earth. It focuses on microbial roles in the carbon and nitrogen cycles, decomposition, respiration, fermentation, methane production, nitrogen fixation, nitrification, and denitrification. The episode also highlights how microbes influence ecosystems, climate, and...

Chapter 3, Episode 5 This episode explains how clinical laboratories identify microbes using a stepwise, evidence-based approach, combining culture, staining, biochemical tests, and molecular methods. You’ll see how rapid, accurate identification guides treatment decisions and why no single test is sufficient on its own.

Chapter 3, Episode 4 This episode covers how microscopes and stains allow microbiologists to visualize and interpret microorganisms, emphasizing magnification, resolution, and contrast. You’ll learn when light vs. electron microscopy is used and how staining techniques, especially the Gram stain, provide critical diagnostic information.

Chapter 3, Episode 3 This episode focuses on isolation as a foundational microbiology skill, explaining why pure (axenic) cultures are essential for accurate identification. You’ll learn how streak plates, spread plates, and pour plates physically separate microbes and why contamination and mixed cultures complicate interpretation.

Chapter 3, Episode 2 This episode explores culture media as diagnostic tools, explaining how media are classified by physical state, chemical composition, and function (general-purpose, enriched, selective, and differential). You’ll learn how microbiologists choose media to encourage growth, suppress competitors, and reveal metabolic traits critical for identification. 

Chapter 3, Episode 1 This episode introduces the "Five I's;" Inoculation, Incubation, Isolation, Inspection, and Identification, and explains how they provide a logical framework for working with microorganisms in both teaching and clinical labs. You’ll learn how these steps guide everything from culturing microbes to making reliable identifications. "The Five I's" crea...

Chapter 9, Episode 39 This episode covers bacterial reproduction through binary fission, generation time and exponential growth, and the phases of the microbial growth curve. It also introduces methods for measuring population size, including turbidity measurements, direct cell counts, and viable plate counts (CFU).

Chapter 9, Episode 38 This episode introduces symbiotic relationships, including mutualism, commensalism, parasitism, and antagonism. It also covers microbial interactions within communities, with emphasis on biofilms, polymicrobial environments, and quorum sensing as a mechanism for communication and coordinated behavior.

Chapter 9, Episode 37 This episode focuses on environmental factors that influence microbial growth, including temperature classifications, oxygen requirements, and pH preferences. It also introduces reactive oxygen species and detoxifying enzymes, osmotic and pressure conditions, and the impact of these factors on microbial survival and distribution.

Chapter 9, Episode 36 This episode covers how microbes are classified based on carbon sources (autotrophs vs. heterotrophs) and energy sources (phototrophs vs. chemotrophs). It introduces combined nutritional categories, growth factors, and the role of the cell membrane in nutrient uptake, including transport mechanisms such as diffusion, facilitated diffusion, active transport, and group transloc...