Dec 7, 2025 · Bacteria are microscopic single-celled organisms that inhabit virtually all environments on Earth, including the bodies of multicellular animals. Bacteria lack a membrane-bound nucleus and …

Dec 12, 2025 · Gram-negative bacterium, any of various types of bacteria that are characterized by having a thin peptidoglycan cell wall surrounded by an outer membrane containing …

Dec 4, 2025 · Microbiology - Bacteria, Viruses, Fungi: The major groups of microorganisms—namely bacteria, archaea, fungi (yeasts and molds), algae, protozoa, and viruses—are summarized below. …

Nitrogen is a component of proteins and nucleic acids and is essential to life on Earth. Although nitrogen is abundant in the atmosphere, most organisms cannot use it in that form. Nitrogen-fixing bacteria …

Dec 19, 2025 · A bacteriophage is any of a group of viruses that infect bacteria. Bacteriophages were discovered independently by Frederick W. Twort in Great Britain (1915) and Felix d’Herelle in France …

Human microbiome, the array of microorganisms that live on and in humans and, more specifically, the collection of microbial genomes that contribute to the broader genetic portrait, or metagenome, of a …

Enterobacter, any of a group of rod-shaped bacteria of the family Enterobacteriaceae. Enterobacter are gram-negative bacteria and are classified as facultative anaerobes. Many species possess flagella …

Dec 19, 2025 · streptococcus, (genus Streptococcus), group of spheroidal bacteria belonging to the family Streptococcaceae. The term streptococcus (“twisted berry”) refers to the bacteria’s …

Dec 17, 2025 · Lactobacillus, (genus Lactobacillus), any of a group of rod-shaped, gram-positive, non-spore-forming bacteria of the family Lactobacillaceae. Similar to other genera in the family, …

Plankton, marine and freshwater organisms that, because they are nonmotile or too small or weak to swim against the current, exist in a drifting state. Plankton is the productive base of both marine and …