Biology

Hematopoiesis is the regulated production of blood cells and platelets from stem and progenitor cells throughout development and adult life.

Hemoglobin is an iron-containing protein that transports oxygen in blood, helps carry carbon dioxide, and contributes to acid–base balance.

A histone is a DNA-associated protein that helps organize chromatin and regulate access to genetic information.

A homologous chromosome is one of a corresponding pair that carries the same genes at matching locations, although their alleles may differ.

Homologous recombination exchanges or copies information between similar DNA sequences, supporting DNA repair, chromosome inheritance, and genetic variation.

Horizontal gene transfer is the movement of genetic material between organisms outside ordinary parent-to-offspring inheritance, shaping genome evolution and microbial adaptation.

The evolutionary history of humans and their extinct relatives, reconstructed through fossils, archaeology, comparative biology, and genetics.

The international research program that mapped and sequenced the human genome, establishing a foundation for modern genomics.

An immune checkpoint is a regulatory pathway that controls immune responses, helps protect healthy tissues, and can be targeted by cancer immunotherapy.

Immune tolerance is antigen-specific non-responsiveness that protects the body’s own tissues and limits inappropriate immune reactions.

Immunoglobulin G is the predominant antibody class in human blood, supporting pathogen defense, immune memory, and maternal antibody transfer.

Immunological memory is the persistence of immune changes after antigen exposure that enables faster, more effective responses upon subsequent encounters.

Inbreeding is reproduction between genetically related individuals, increasing homozygosity and potentially reducing offspring survival and reproductive success.

Innate immunity comprises rapid, inherited defense mechanisms that detect microbes, restrict infection, and help initiate adaptive immune responses.

Interferons are signaling proteins that coordinate antiviral defenses and regulate immune responses through changes in gene expression.

Interleukin-2 is a cytokine that regulates lymphocyte growth, immune responses, and the maintenance of regulatory T cells.

An intron is a transcribed segment of a gene that is removed from precursor RNA during splicing.

A membrane protein that forms a selective pore through which ions move, enabling electrical signaling, secretion, sensory detection, and cellular regulation.

American neuroscientist and psychiatrist known for developing optogenetics and hydrogel-based methods for studying intact tissues.

A kinetochore is a chromosome-associated protein assembly that couples chromosomes to spindle microtubules and coordinates their segregation during cell division.

A leukocyte, or white blood cell, is an immune-system cell involved in defending the body against infection and coordinating immune responses.

Louis Pasteur was a French chemist and microbiologist whose research transformed understanding of fermentation, infectious disease, and vaccination.

Lymphocytes are white blood cells central to adaptive and innate immunity, comprising B cells, T cells, and natural killer cells.

A macrophage is a tissue-associated immune cell that engulfs microbes and cellular debris, coordinates immune responses, and supports tissue maintenance and repair.

The major histocompatibility complex is a gene region encoding immune proteins, especially molecules that present peptide antigens to T cells.

Meiosis is a specialized form of cell division that halves chromosome sets and reshuffles genetic information during sexual reproduction.

Membrane potential is the electrical potential difference across a biological membrane, arising from ion gradients and selective permeability and supporting electrical signaling, transport, and energy conversion.

A memory B cell is a long-lived, antigen-experienced lymphocyte that supports a rapid antibody response when a previously encountered antigen returns.

Messenger RNA carries genetic information to ribosomes, where its sequence directs protein synthesis.

Metabolism is the coordinated network of chemical reactions through which living organisms obtain energy, build cellular components, and maintain biological functions.

Microbiology studies microorganisms and viruses, examining their structure, functions, diversity, interactions, and roles in health, industry, and the environment.

A microorganism is a microscopic organism belonging to diverse groups that sustain ecosystems, interact with hosts, and support industrial and scientific processes.

A microtubule is a hollow tubulin polymer that organizes cells, supports intracellular transport, enables chromosome segregation, and forms the structural core of cilia and flagella.

A mitochondrion is a double-membrane organelle that produces ATP and participates in metabolism, cellular signaling, and programmed cell death.

Mitosis is eukaryotic nuclear division that separates duplicated chromosomes into two daughter nuclei, normally preserving chromosome number and genetic information.

A dynamic microtubule-based apparatus that aligns and separates duplicated chromosomes during mitosis.

Molecular biology studies the molecular mechanisms of life, particularly how genetic information is stored, expressed, regulated, and transmitted.

Mosaicism is the presence of genetically distinct cell populations derived from a single fertilized egg within one organism or tissue.

A mutation is a lasting change in genetic material that can generate biological variation, alter cellular functions, and contribute to evolution or disease.

Myelin is a multilayered, lipid-rich sheath around nerve-cell axons that accelerates electrical signaling and supports axonal function.

A natural killer cell is an innate immune lymphocyte that kills susceptible abnormal cells and regulates immune responses through cytokine secretion.

Natural selection is differential reproductive success associated with heritable variation, changing populations across generations and producing adaptations.

A neuron is a specialized nerve cell that receives, processes, and transmits information through electrical and chemical signals.

Neuroplasticity is the nervous system’s capacity to change its structure, connections, and function through development, experience, learning, and responses to injury.

Neuroscience is the interdisciplinary study of the nervous system, examining its structure, development, function, and relationship to behavior and disease.

A neurotransmitter is a chemical messenger released by a neuron that changes the activity of another cell through specific receptors.

A neutrophil is a granular white blood cell that rapidly responds to infection and tissue injury through migration, phagocytosis, and antimicrobial activity.

Nitrification is the microbial oxidation of ammonia or ammonium to nitrite and then nitrate, a major transformation in the nitrogen cycle.

A DNA repair pathway that reconnects double-strand breaks without requiring an extensive homologous template.

Nucleic acids are nucleotide polymers that store, transmit, and express genetic information and perform structural, regulatory, and catalytic functions.

A nucleosome is the basic repeating unit of eukaryotic chromatin, consisting of DNA wrapped around a core of histone proteins.

A nucleotide is a phosphorylated sugar–base compound that forms nucleic acids and participates in cellular energy transfer, metabolism, and signaling.

Opsonization is the coating of a target with molecules that enhance its recognition and uptake by phagocytic immune cells.

Osmosis is the net movement of solvent through a selectively permeable membrane, driven by differences in solvent chemical potential.

Oxidative phosphorylation couples respiratory electron transfer to ATP synthesis through an electrochemical gradient across a biological membrane.

A biological agent capable of causing disease in a susceptible host.

Peptidoglycan is a mesh-like polymer of sugars and short peptides that strengthens most bacterial cell walls and is continually rebuilt during growth and division.

Peripheral immune tolerance restrains mature lymphocytes outside primary lymphoid organs, preventing harmful responses to self and harmless environmental antigens.

Phagocytosis is the cellular engulfment of large particles, supporting nutrition, immune defense, and the removal of dead cells and tissue debris.

A phenotype is an organism’s observable or measurable characteristics, arising from its genetic constitution, environmental influences, and development.