Biology

Scar

Scar: formation, types, and clinical significance

Schistosoma mansoni

Schistosoma mansoni: intestinal blood fluke and cause of schistosomiasis

Sclera

Sclera: structure, function, and clinical significance

Scleractinia

Scrotum

Scrotum: anatomy, function, and clinical significance

Scute

Scute: bony external plate or thickened scale

Sebaceous gland

Secondary palate

Secondary sex characteristic

Secretin

Secretin: physiology, history, and clinical significance

Secretion

Segmentation

Segmentation in Biology

Selectable marker

Selectable marker (molecular biology)

Selenocysteine

Self-replication

Self-replication: biological, molecular, digital and cultural processes

Selfish DNA

Selfish DNA: noncoding sequences that propagate within genomes

Semen

Seminal vesicle

Seminiferous tubule

Seminiferous tubule — structure, function and clinical significance

Sensory receptor

Sensory receptor: how organisms detect and convert stimuli

Sensory system

Sensory system: how organisms detect and interpret their surroundings

Sequence analysis

Sequence analysis: methods, applications, and interpretation in biology

Sericulture

Sericulture: the cultivation and production of silk

Serosa

Serosa (serous membrane): structure, function, and clinical relevance

Serotonin

Serotonin (5‑Hydroxytryptamine): Roles, Biology, and Clinical Significance

Sertoli cell

Sertoli cell: supporting cells of the testis and guardians of spermatogenesis

Serum (blood)

Serum (blood component): composition, preparation, and uses

Sex

Sex (biological reproduction)

Sex hormone

Sex hormones (sex steroids): overview, synthesis, functions, and clinical significance

Sex linkage

Sex organ

Human Genitalia: Anatomy, Function, and Cultural Context

Sexual conflict

Sexual conflict (evolutionary biology)

Sexual dimorphism

Sexual intercourse

Sexual reproduction

Sexual selection

Sexual selection: mechanisms, examples, and evolutionary significance

Shell

Shell (biological coverings, casings, computing and uses)

Shigella

Shigella: bacterial genus that causes shigellosis and severe diarrheal disease

Sibling species

Sight

Sight (Vision): How Eyes and the Brain Create Visual Perception

Signal recognition particle

Signal transduction

Silkworm

Silkworm (Bombyx mori) — the domesticated silk-producing caterpillar

Single nucleotide polymorphism

Siphon (mollusc)

Molluscan siphons: form and function in gastropods, bivalves, and cephalopods

Overview of molluscan siphons: tubular mantle extensions in gastropods, bivalves and cephalopods—their forms, roles in breathing, feeding, locomotion and sensing, and how designs v

Sipuncula

Sirenomelia

Sister group

Sister group (sister taxon) — closest relatives in phylogenetics