Biology
Articles about living organisms, life processes and biological research.
Stillbirth
Stillbirth: causes, diagnosis, and support
Stomach
Stomach (anatomy, function, and clinical notes)
The stomach is a muscular organ of the digestive tract that stores and breaks down food using mechanical action and acid‑activated enzymes; this article covers structure, function,
Stonefly
Stonefly (Plecoptera): freshwater insects of cold, running water
Stop codon
Stop codon: signal that ends translation in the genetic code
A stop codon is a three‑nucleotide signal in mRNA that terminates translation. This article explains the common stop codons, molecular mechanism, biological exceptions, medical rel
Strain (biology)
Strangulation
Streptococcus
Streptococcus: biology, taxonomy, clinical roles and laboratory identification
Streptococcus mutans
Streptomyces
Streptomyces: filamentous soil bacteria and prolific producers of antibiotics
Stress (biology)
Stress (biology): physiological and psychological responses
Stromule
Stromules: Dynamic Tubular Extensions of Plastids in Plant Cells
Struggle for existence
Subcutaneous tissue
Subcutaneous tissue (hypodermis)
Suberin
Subgenus
Sublingual gland
Submandibular gland
Subphylum
Substantia nigra
Substantia nigra: structure, function, and clinical importance
Substrate
Substrate: biological, chemical, geological, and technological contexts
Sue (dinosaur)
Sue (Tyrannosaurus rex): discovery, history and scientific importance
Superphylum
Suprachiasmatic nucleus
Suprachiasmatic nucleus: mammalian master circadian pacemaker and light-entrained clock
Survival of the fittest
Survival of the Fittest: Meaning, History, and Common Misunderstandings
Survivor
Swallowing
Sweat
Swim
Swimming: movement in water, skills, history, and modern uses
Swim bladder
Swim bladder: structure, function, and evolutionary significance
Swine influenza
Swine influenza (swine flu): overview, strains, transmission and prevention
Symbiosis
Symmetry (biology)
Symmetry in Biology
Sympathetic nervous system
Synapomorphy
Synapomorphy: shared derived traits in cladistics
Synapsid
Synapsid: the lineage that produced mammals
Syncytium
Syncytium: multinucleate tissues and their biological roles
Synovial fluid
Synovial fluid: composition, function, and clinical importance
Synthetic genomics
Synthetic genomics: design, assembly and uses of artificial genomes
Systema Naturae
Systema Naturae: Linnaeus's Classification of Plants, Animals and Minerals
Systematics
Systematics: study of organismal diversity, relationships, and evolutionary history
Systole
Systole (cardiac contraction)
Systole is the phase of the cardiac cycle when the heart's chambers contract to eject blood. It includes mechanical steps, electrical control, clinical significance and distinction
T cell
T helper cell
T2 phage
Tactopoda
Tactopoda (proposed clade within Ecdysozoa)
Tandem repeat
Tandem repeat (DNA)
Tapeworm
Taste
Taste (gustation): how we perceive basic tastes and flavor