Biology

Photorespiration recycles products of Rubisco oxygenation, recovering carbon while consuming energy and releasing carbon dioxide.

Photosynthesis converts light into chemical energy, supporting most food webs and supplying the oxygen released by plants, algae, and cyanobacteria.

A photosystem is a membrane-bound pigment–protein complex that captures light and drives electron transfer during photosynthesis.

Phylogenetics is the study and inference of evolutionary relationships among organisms, genes, and other biological entities.

A plasma cell is a differentiated B lymphocyte specialized for antibody secretion, contributing to immediate defense and long-term humoral immunity.

A plasmid is an independently replicating DNA element that commonly carries accessory genes and serves as a tool for genetic research.

Anucleate cellular fragments in blood essential for hemostasis, clot formation, and immune surveillance.

Polyadenylation adds an adenosine-rich tail to RNA, influencing messenger RNA maturation, translation, stability, and degradation.

Polymerase chain reaction is a laboratory technique that selectively amplifies DNA through repeated cycles of strand separation, primer binding, and enzymatic synthesis.

Population genetics studies genetic variation within and between populations and the processes that change allele frequencies across generations.

A prokaryote is an organism whose cells lack a membrane-bound nucleus, encompassing bacteria and archaea.

A promoter is a DNA region that directs the initiation of transcription and helps determine when, where, and how strongly a gene is expressed.

Proteins are chains of amino acids that fold into three-dimensional shapes and carry out most catalytic, structural, signaling and defensive functions in living cells.

The Protein Data Bank is a global archive of three-dimensional biological macromolecular structures, associated experimental data, and descriptive metadata.

Protein folding is the process by which a polypeptide acquires its three-dimensional structure, governed by its sequence, physical interactions, and environment.

Proton-motive force is the electrochemical potential difference across a membrane that drives proton transport, ATP synthesis, and other cellular processes.

A reading frame specifies how a nucleotide sequence is divided into consecutive three-base codons during protein synthesis.

Receptor editing changes antigen-receptor specificity through additional gene rearrangements, helping developing B cells avoid self-reactivity.

Recombinant DNA consists of DNA segments joined through laboratory methods and is used to study genes, produce biological products, and engineer organisms.

A regulatory T cell is a specialized T lymphocyte that restrains immune responses, maintains self-tolerance, and helps control inflammation.

Ribosomal RNA forms the structural and catalytic core of ribosomes, enabling protein synthesis and providing markers for evolutionary and microbial studies.

A ribosome is an RNA–protein complex that translates messenger RNA into proteins by decoding genetic instructions and catalyzing peptide-bond formation.

A ribozyme is an RNA molecule that catalyzes a chemical reaction, demonstrating that RNA can function as both an information carrier and a biological catalyst.

RNA is a nucleic acid that carries genetic information, enables protein synthesis, regulates gene expression, and can catalyze chemical reactions.

RNA polymerase is an enzyme that synthesizes RNA from a nucleic-acid template, enabling transcription, gene expression, and the replication of many RNA viruses.

RNA sequencing identifies and quantifies RNA molecules in biological samples, revealing gene expression, transcript structure, and cellular diversity.

RNA splicing removes introns and joins exons in RNA transcripts, helping produce mature RNAs and regulate gene expression.

Rubisco is the enzyme that catalyzes carbon dioxide fixation in the Calvin cycle and also initiates photorespiration through a competing oxygenation reaction.

Somatic hypermutation introduces mutations into antibody genes in activated B cells, supplying variation for affinity maturation.

Speciation is the evolutionary process through which populations diverge into distinct species, often through the development of reproductive isolation.

A species is a fundamental biological grouping whose boundaries are identified using reproductive, morphological, ecological, and genetic evidence.

A dynamic RNA–protein complex that removes introns from precursor messenger RNA and joins exons during eukaryotic gene expression.

Starch is a glucose-based carbohydrate that stores energy in plants and serves as a major food component and industrial raw material.

A synapse is a specialized junction through which a neuron communicates with another neuron or a target cell by chemical or electrical signaling.

A T cell is a thymus-maturing immune cell that recognizes antigens, coordinates immune responses, kills abnormal cells, and contributes to immune memory and tolerance.

T-cell costimulation comprises receptor-mediated signals that complement antigen recognition and regulate T-cell activation, proliferation, survival, and differentiation.

The T-cell receptor is a membrane-bound protein complex that enables T cells to recognize antigens and initiate immune signaling.

Taxonomy is the science of identifying, describing, naming, and classifying organisms, providing a framework for studying biological diversity and evolutionary relationships.

A thylakoid is a membrane-bound compartment that supports the light-dependent reactions of photosynthesis in chloroplasts and most cyanobacteria.

Transcription is the enzyme-mediated synthesis of RNA from a DNA template, enabling gene expression and the production of functional RNAs.

A transcription factor is a protein that regulates transcription, usually by recognizing regulatory DNA sequences and influencing the transcription machinery.

Transfer RNA is a small RNA molecule that decodes messenger RNA codons and carries amino acids to ribosomes during protein synthesis.

Translation is the ribosome-mediated synthesis of a polypeptide according to the nucleotide sequence of messenger RNA.

A transposable element is a mobile DNA sequence that can relocate or generate new copies within a genome, influencing genome structure, gene regulation, and evolution.

V(D)J recombination assembles antigen-receptor genes in developing lymphocytes, generating much of the diversity required for adaptive immunity.

A virus is an acellular infectious agent that replicates within host cells and carries genetic information as DNA or RNA.

Warren McCulloch was an American neurophysiologist whose work connected neural activity, mathematical logic, and cybernetics.

A sex chromosome involved in inheritance, development, and gene-dosage regulation in humans and many other animals.