Biology
Articles about living organisms, life processes and biological research.
Skeletal muscle
Skeleton
Skene's gland
Skene's glands (paraurethral glands)
Skin
Skin: structure, functions, variation, and human significance
Comprehensive overview of skin as an organ and animal covering: its structure, functions, variation among species, health and care, evolutionary background, and cultural uses.
Skull
Skull (cranium): structure, function, and diversity
Sleep
Sleep: biology, stages, functions, patterns and health
Sleeping Beauty transposon system
Slime mould
Slime moulds: biology, life cycle, ecology, and scientific importance
Small interfering RNA
Small interfering RNA (siRNA)
Small intestine
Smooth muscle
Snakefly
Sneeze
Sneeze: reflex, causes, health implications and cultural notes
snRNP
Small nuclear ribonucleoproteins (snRNPs)
Somatic cell
Somatic Cell: Definition, Characteristics, Development and Significance
Somatic nervous system
Somatosensory system
Soricomorpha
Spawn (biology)
Speciation
Speciation: How new species arise and the mechanisms involved
Sperm
Spermatophore
Spermatophore: Packaged Sperm and Its Role in Animal Reproduction
Spider silk
Spike protein
Spike protein (viral surface glycoprotein)
Spine
Spine (vertebral column): structure, function, evolution and health
Spiracle
Spirillum
Spirillum — spiral-shaped bacteria: morphology, taxonomy and significance
Spirochaetaceae
Spirochaete
Spirochaete (Spirochaetae) — helical, motile bacteria and their significance
Spliceosome
Spliceosome: cellular machinery for pre-mRNA splicing
Sporangium
Sporangium: enclosure for spores and its role in plant and fungal life cycles
Spore
Squamosal bone
Staining
Stalking
Stalking: animal behavior, human harassment, law, and prevention
Staphylococcaceae
Staphylococcaceae: family of Gram‑positive cocci
Staphylococcus
Staphylococcus — genus of gram-positive cocci bacteria
Staphylococcus aureus
Starvation
Starvation: causes, physiology, signs, history, and recovery
Steganinae
Steganinae — a subfamily of Drosophilidae
Stem
Stem cell
Stem cell: biology, types, and medical significance
Sterile
Sterilisation
Sterilisation: permanent prevention of reproduction
Sterilization (microbiology)
Sternum
Sternum (breastbone): structure, function, and comparative anatomy
Steroid
Steroid: structure, types, biological roles and medical uses
Steroids are organic compounds with a characteristic four‑ring core. This article explains their structure, natural occurrence, major classes (hormones, sterols, synthetic drugs),
Steropodontidae
Steropodontidae: Early Cretaceous monotremes of Australia