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A-B-C-D-E-F-G-H-I-J-K-L-M-N-O-P-Q-R-S-T-U-V-W-X-Y-Z
- Habitat
- The type of site where an organism normally lives.
- Habituation
- The process of becoming accustomed to something.
- Half-life
- The time needed for (1) half the atoms of a radioactive substance to decay or (2) half the amount of a substance (e.g., a drug) to be metabolized or excreted.
- Hallucinogen
- A substance that induces hallucinations.
- Haltere
- [diptera]
- HAMA
- human antimouse antibodies
- Haploid
- Having only a single set of chromosomes (n) as is present in gametes. Also called monoploid.
- HDL (high-density lipoprotein]
- [and cholesterol]
- Heart, human
- anatomy
- Helicase
- [DNA opening]
- Helicobacter pylori
- [genome]
- helix-turn-helix proteins
- Helper T cells
- [Discussion] [interaction with B cells]
- Hemagglutinin
- of influenza virus
- Hematocrit
- Hemizygous
- Genes present in only one copy, not two, in an otherwise diploid cell or individual. Human males are hemizygous for most of the genes on the X chromosome.
- Hemoglobin
- A red, iron-containing protein that transports oxygen and carbon dioxide in the blood of vertebrates and some invertebrates. [More]
- Hemophilia
- Clotting disorder caused by lack of a clotting factor. [Discussion] [Inheritance]
- Hemophilus influenzae
- [genome]
- Hepatic portal system
- Herbaceous
- Nonwoody.
- Herbicides
- Herbivore
- An animal that eats plants.
- Herceptin
- Hertz
- Cycles per second.
- Heterodimer
- Complex of two different proteins.
- Heterogamy
- Condition in which the two gametes are unlike in structure (e.g., sperm and eggs).
- Heterotrophic
- Requiring a supply of organic compounds (food) from the environment. [ More ]
- Heterozygous
- Having two different alleles (e.g., A and a) at the corresponding gene loci on homologous chromosomes.
- Hexose
- A sugar containing six carbon atoms. Glucose is a hexose. [Discussion]
- Hippocampus
- Histidine
- [structure]
- Histocompatibility molecules
- [class I] [class II] [minor] [genes that encode them]
- Histone
- One of a set of basic proteins associated with the chromosomes of eukaryotes.
- [More]
- HIV-1
- Retrovirus that causes AIDS. [More] [and apoptosis] [cell receptors for]
- HLA
- human leukocyte antigen
- [structure of class I] [genes]
- Homeobox
- A sequence of 180 base pairs which encodes a 60-amino acid homeodomain found in many DNA-binding proteins. Genes containing homeoboxes are found in all eukaryotic genomes.
- Homeostasis
- Maintenance of a relatively constant internal environment (ECF).
- Homeothermic
- Having a constant body temperature above that of the usual surroundings; therefore, "warm-blooded".
- Hominid
- Group of primates to which humans and their ancestors (but not the great apes) belong.
- Hominoid
- Group of primates that includes humans, their ancestors (thus all hominids), as well as the great apes (pongids).
- Homodimer
- Complex of two identical protein molecules.
- Homologous
- Showing a fundamental similarity of structure because they have been inherited from a common ancestor. Applied to structures ranging from organs to molecules.
- [chromosome pairs]
- Homozygous
- Having identical alleles (e.g., AA or aa) at the corresponding gene loci on homologous chromosomes.
- Hormone
- Substance secreted by cells in one part of the body which, after being transported by body fluids, exerts an effect on the activities of cells elsewhere in the body. [Hormones of humans]
- Hox gene clusters
- [in Drosophila, mouse, and human]
- Human papilloma virus (HPV)
- [interaction with tumor suppressor genes] [and apoptosis]
- hunchback (hb)
- [role of gene in Drosophila segmentation]
- Huntington's disease
- [mutation]
- Humus
- Organic matter in the soil.
- Hybrid
- Organism produced by genetically dissimilar parents. It is heterozygous for one or (more often) many pairs of genes.
- Hydrocarbon
- A compound containing only carbon and hydrogen. Characteristic of petroleum and coal.
- Hydrogen bond
- The noncovalent attraction between a hydrogen atom covalently attached to one strongly electronegative atom (e.g., O, N) and another strongly electronegative atom (e.g., O, N) located nearby. [More]
[in DNA]
- Hydrolysis
- Decomposition of a substance by the insertion of water molecules between certain of its bonds. Food is digested by hydrolysis.
- Hydronium ion
- Hydrophilic
- Used to describe molecules or molecular groups that are attracted to water and other polar solvents.
- Hydrophobic
- Used to describe molecules or molecular groups that mix poorly with water. Hydrocarbons and fats are hydrophobic. [hydrophobic interactions between macromolecules]
- Hypercholesterolemia
- [familial]
- Hydroxyl group
- [Structure]
- Hypertonic
- Having a lower concentration of water than the solution under comparison. [More]
- Hypocotyl
- That portion of the shoot of a plant embryo or seedling below the node to which the cotyledons are attached. [More]
- Hypothalamus
- hormones of
- Hypotonic
- Having a greater concentration of water than the solution under comparison. [More]