Search results
Results from the WOW.Com Content Network
A homologue (also spelled as homolog) is a compound belonging to a homologous series. [1] Compounds within a homologous series typically have a fixed set of functional groups that gives them similar chemical and physical properties. (For example, the series of primary straight-chained alcohols has a hydroxyl at the end of the carbon chain ...
The example above is an example alloparalogy. Symparalogs are paralogs that evolved from gene duplication of paralogous genes in subsequent speciation events. From the example above, if the descendant with genes A1 and B underwent another speciation event where gene A1 duplicated, the new species would have genes B, A1a, and A1b.
Homologous sequences are paralogous if they were created by a duplication event within the genome. For gene duplication events, if a gene in an organism is duplicated, the two copies are paralogous. They can shape the structure of whole genomes and thus explain genome evolution to a large extent. Examples include the Homeobox genes in animals.
In organic chemistry, a homologation reaction, also known as homologization, is any chemical reaction that converts the reactant into the next member of the homologous series. A homologous series is a group of compounds that differ by a constant unit, generally a methylene (−CH 2 −) group.
Alkyl groups form homologous series. The simplest series have the general formula −C n H 2n+1. Alkyls include methyl, (−CH 3), ethyl (−C 2 H 5), propyl (−C 3 H 7), butyl (−C 4 H 9), pentyl (−C 5 H 11), and so on. Alkyl groups that contain one ring have the formula −C n H 2n−1, e.g. cyclopropyl and cyclohexyl.
Methane is part of a homologous series known as the alkanes, which contain single bonds only. In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. [1]: 620 Hydrocarbons are examples of group 14 hydrides.
On the other hand, similarity has to do with the sequences being compared having similar residues quantitatively. For example, in terms of nucleotide sequences, pyrimidines are considered similar to each other, as are purines. Similarity ultimately leads to homology, in that the more similar sequences are, the closer they are to being homologous.
Homology model of the DHRS7B protein created with Swiss-model and rendered with PyMOL. Homology modeling, also known as comparative modeling of protein, refers to constructing an atomic-resolution model of the "target" protein from its amino acid sequence and an experimental three-dimensional structure of a related homologous protein (the "template").