H

High score
In the results of a BLAST search, the scores of the highest-scoring HSP found with each database sequence is listed in the "high score" column.

Homologous Describing features of organizms that have the same evolutionary origin but have developed different functions. For example the wings of a bat, the flippers of a dolphin, and the arms of a human are homogous organs, having evolved from the paired pectoral fins of a fish ancestor.

Homologous chromosomes Chromosomes having the same structural features.Homologous chromosomes have the same pattern of genes along the chromosome but the nature of the genes may differ.

Homologous sequences. Orthologs and Paralogs are two types of homologous sequences. Orthology describes genes in different species that derive from a common ancestor. Orthologous genes may or may not have the same function. Paralogy describes homologous genes within a single species that diverged by gene duplication.

Homology Similarity attributed to descent from a common ancestor.

Homotopic Two identical functional groups with exactly the same chemical connectivity and in identical chemical environments.

Homozygous is possessing two identical forms of a particular gene, one inherited from each parent.

Hooke's Law states that the stress applied to any solid is proportional to the strain it produces within the elastic limit for that solid. In molecular modeling Hooke's Law is applied to bond stretching in the Force Field.

Human artificial chromosome (HAC) is a vector used to transfer or express large fragments of human DNA. HACs behave and are constructed like human chromosomes.

Human Genome Project is an international research project to map each human gene and to completely sequence human DNA.

Hybridization is base pairing of two single strands of DNA or RNA.

Hydrogen bonding involves the interaction of a "non-bonded" (i.e. not covalently bonded) pair of electrons on one atom interacting with a hydrogen atom involved in a polar "H--X" bond. In proteins "X" is almost always a nitrogen or oxygen.

The electronegativity of "X" relative to hydrogen causes the hydrogen atom to be electron deficient (this is sometimes shown as a partial positive charge, d+). A hydrogen bond is formed when this partially positive hydrogen is attracted to a lone pair of electrons on a nearby atom (again, in proteins this is almost always a nitrogen or an oxygen).

In proteins, X and Y are most commonly oxygen or nitrogen.

The group bearing the hydrogen is considered the hydrogen bond donor. The other group is considered hydrogen bond acceptor.

Hydrophilic "Water loving". Those functional groups or molecules which prefer to be in an aqueous environment or in proteins, those amino acids which prefer to be in an aqueous environment.

Hydrophobic "Water hating". Those functional groups or molecules which prefer to be in an environment where there is no water; an oily environment.

Author: Tug Sezen