Fluorescence Microscopy: How Light Reveals the Living Cell
Fluorescence microscopy uses fluorescent molecules to label and visualize specific structures inside biological specimens.
Biology and Life Sciences
57 glossary terms
Biology and life sciences cover everything from the molecular machinery inside a single cell to the evolutionary forces that shape whole ecosystems. The terms in this section span genetics, anatomy, microbiology, ecology, and the frontier where biology meets chemistry and computation. Some are classroom staples like the double helix or photosynthesis. Others capture ideas you may never have encountered, from horizontal gene transfer to zygotic gene activation. Together they form the vocabulary scientists use to describe how life works, how it began, and how it continues to surprise us.
Endosymbiotic Theory: How Bacteria Became Organelles
Endosymbiotic theory explains how eukaryotic cells acquired mitochondria and chloroplasts by engulfing free-living bacteria that became permanent, integrated organelles.
Epigenetic Inheritance: How Molecular Marks Pass Between Generations
Epigenetic inheritance transmits changes in gene expression across generations without altering the DNA sequence, through DNA methylation, histone modification, and small RNA pathways.
CRISPR Gene Editing: How Bacterial Scissors Rewrote Medicine
CRISPR gene editing is a molecular biology technique that uses a bacterial protein called Cas9, directed by guide RNA, to alter specific DNA sequences in living organisms.
Double Helix: DNA's Iconic Structure Explained
The double helix is the twisted-ladder shape formed by two strands of DNA wound around each other, encoding genetic instructions for all living organisms.
Capillary Action: How Water Defies Gravity in Plants
Capillary action is the movement of a liquid through narrow spaces against gravity, driven by adhesion, cohesion, and surface tension. In plants, it draws water upward through the xylem.
Cambrian Explosion: When Animal Life Took Shape
The Cambrian Explosion is the rapid diversification of animal life that began approximately 538.8 million years ago, producing most major animal body plans within roughly 13 to 25 million years.
Bottleneck Effect: How Populations Lose Their Genetic Diversity
The bottleneck effect is a form of genetic drift in which a population's size drops sharply, leaving survivors with only a fraction of the original genetic variation.
Base Pair Mutations: How Single DNA Changes Shape Biology
A base pair mutation is a change in one or more nucleotide bases within a DNA sequence, affecting gene function and shaping both disease and evolution.
Bacterial Conjugation: How Bacteria Share DNA
Bacterial conjugation is the transfer of genetic material from one bacterial cell to another through direct physical contact, typically mediated by a hair-like structure called a pilus.