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H

HAART
Highly Active AntiRetroviral Therapy (for AIDS)
Habitat
The type of site where an organism normally lives.
Habituation
Haeckel, E.
Hair cells
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.
Haltere
HAMA
human antimouse antibodies
Ham's medium
Haploid
Having only a single set of chromosomes (n) as is present in gametes. Also called monoploid.
Haplotype
Hardy-Weinberg equilibrium
Harlequin chromosomes
Haversian canal
HDL (high-density lipoprotein)
Hearing, sense of
Heart
[anatomy of human heart ] [ control of human heart ] [ fish heart ] [ frog and lizard hearts ] [ squid hearts ]
Heat receptors
Heat transport
Hedgehog signaling
HeLa cells
Helicase
Helicobacter pylori
[adaptation to stomach]
Helix-turn-helix proteins
Helminth
General term for any member of three groups of parasitic "worms": flukes (trematodes), tapeworms (cestodes), and roundworms (nematodes).
Helper T cells
[Discussion] [Interaction with B cells]
Hemagglutinin
of influenza virus
Hematocrit
Heme
Hemidesmosomes
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] [sickle-cell] [in different species]
Hemophilia
[A, B, C] [Inheritance]
Hemophilus influenzae
[vaccine]
Heparan sulfate
Heparin
Hepatic portal system
Hepatitis B
HER1 and HER2
Herbaceous
Nonwoody.
Herbicides
Herbivore
An animal that eats plants.
Hereditary angioedema (HAE)
Heritability
Herpesviruses
Hershey, A. D.
Hertz
Cycles per second.
Heterochromatin
Heterodimer
Complex of two different proteins.
Heteroduplex DNA
Heteroplasmy
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.
Hexapoda (the insects)
Hexose
Hippocampus
Histidine
Histocompatibility molecules
[class I] [class II] [minor] [genes that encode them] [structure of HLA-A2]
Histones
[ histone acetyltransferases (HATs) ] [ histone deacetylases (HDACs) ]
HIV, the Human Immunodeficiency Virus
[how it evades the immune system]
HLA
human leukocyte antigen [structures] [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".
Hominoid
Group of primates that includes hominids and hominins. [Discussion]
Homodimer
Complex of two identical protein molecules.
Homo habilis
Homologous
Showing a fundamental similarity of structure because they have been inherited from a common ancestor. Applied to structures ranging from organs to molecules.
[illustrated discussion] [chromosome pairs]
Homoplasmy
Homozygous
Having identical alleles (e.g., AA or aa) at the corresponding gene loci on homologous chromosomes.
Honeybees (Apis mellifera)
[life history] [honeybee communication]
Hormesis
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. [of humans] [of insects] [sex hormones] [of plants]
Horsetails
Hox gene clusters
[in Drosophila, mouse, and human]
HTLV-1
and adult T-cell leukemia/lymphoma (ATL)
Hubel, D. H.
Human Genome Project (HGP)
Human papilloma virus (HPV)
[interaction with tumor suppressor genes] [and apoptosis] [vaccine]
Humus
hunchback (hb)
[role of gene in Drosophila segmentation]
Huntington's disease
[mutation]
Hutchinson-Gilford progeria syndrome
Hyaluronic acid
Hybrid
Organism produced by genetically dissimilar parents. It is heterozygous for one or (more often) many pairs of genes.
Hybridization
Hydrocarbons
Hydrogen bond
[ 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]
Hydroxyl group
Hydroxyl radical
Hypercholesterolemia, familial
Hypertension
Hypertonic solutions
Hypervariable regions
Hypocotyl
That portion of the shoot of a plant embryo or seedling below the node to which the cotyledons are attached. [View]
Hypothalamus
[hormones of]
Hypothesis
[testing] [null]
Hypotonic solutions
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