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- IAA (Indole-3-acetic acid)
- ICAM-1 (InterCellular Adehesion Molecule-1)
- I-cell disease ("inclusion-cell disease")
- IgA
- A class of antibody molecules abundant in tears, colostrum, and other secretions. [More]
- IgE
- A class of antibodies responsible for certain immediate hypersensitivities (allergies). [More]
- IgG
- The class of antibody molecules that is most abundant in the blood. [More]
- Ilyanassa obsoleta
- Imatinib mesylate (also known as Gleevec® and STI571)
- Immune globulin (IG)
- Immune privilege
- Immune surveillance
- Immune System
- [anatomy] [antigen receptors] [B cells and T cells] [clonal selection] [generation of antigen receptor diversity]
- Immunity
- [adaptive vs. innate] [adaptive immunity in prokaryotes] [cell-mediated] [active vs. passive] [complete list of topics]
- Immunological memory
- Immunological synapse
- Immunological tolerance
- The inability to produce antibodies and/or a cell-mediated immune response to a particular antigen.
- Immunosuppression
- The use of drugs or other agent (e.g., x rays) to inhibit an immune response. [More]
- Immunotoxin
- Impact hypothesis
- Implantation
- Imprinting
- [genomic or parental (the preferential expression of the allele inherited from one parent or the other)] [in animal behavior]
- Inbreeding
- Incretins
- Indels
- Independent assortment of genes
- Indian pipe
- Indole-3-acetic acid
- Industrial melanism
- Inflammasome
- Inflammation
- Influenza
- Ingestion
- Inhibitory postsynaptic potential (IPSP)
- Innate Lymphoid Cells (ILCs)
- Inner Cell Mass
- [of mouse blastocyst] [of human blastocyst]
- Inorganic
- Term describing all compounds that do not contain carbon as well as a few simple carbon-containing substances such as carbon dioxide and the carbonates.
- Inositol-1,4,5-trisphosphate (IP3)
- Insecticides
- Insects
- [insect hormones] [orders of]
- Insertions (in DNA)
- Instincts
- Insulators
- Insulin
- Insulin-like growth factor
- [Igf-1] [Imprinting of Igf-2 gene (as well as that of its receptor)]
- Integral membrane proteins
- Integrase
- Integrins
- [and angiogenesis]
- Inteins
- Interferon-gamma (IFN-γ)
- Interleukins
- Cytokines that regulate development and activities of leukocytes. [in blood cell formation] [interactions with helper T cells]
- Intermediate filaments
- Intermediate host
- Host normally used by a parasite during an immature or larval stage of the parasite's life cycle. [of tapeworms] [of blood flukes]
- Interneuron
- Interphase
- Interstitial fluid
- The fluid lying between, and thus bathing, the cells of animals. Interstitial fluid (also called extracellular fluid — ECF) is derived from blood. Lymph is derived from it.
- Intertidal zone
- Intestine
- Intracytoplasmic Sperm Injection (ICSI)
- Intrauterine devices (IUDs)
- Intrinsic factor
- Introgression
- Intron
- Portion of a gene that is transcribed into RNA but is removed during the formation of the mature RNA molecule. Found in rRNA and tRNA genes as well as in genes encoding proteins. Most eukaryotic genes have introns; most genes in bacteria and archaea do not. [More] [Group I] [Group II]
- Invariant (Ii) chain
- Invertebrates
- Inverted repeats
- In vitro
- Done in the "test tube".
- In Vitro Fertilization (IVF)
- [prior genetic screening]
- In vivo
- Refers to experiments performed in the living organism.
- Iodine
- Ion
- Atom or group of atoms that has an electrical charge arising from the gain or loss of electrons.
- Ion channels in cell membranes
- Ionic bond
- Chemical bond formed between ions of opposite charge. [More]
- Iron
- [nutritional requirement]
- Islets of Langerhans
- Isoleucine
- Isomer
- Molecule with the same molecular formula as another but with a different structural formula (e.g., glucose and fructose). [optical isomers]
- Isometric
- The contraction, without shortening, of a muscle. [More]
- Isotonic
- (1) Adjective to describe the contraction of a muscle that is allowed to shorten as it exerts a steady force. (2) Having the same concentration of water as the solution under comparison. (More)
- Isotope
- Atom that differs in weight from other atoms of the same element because of a different number of neutrons in its nucleus. [Discussion]