|
OR5A1
Olfactory receptor 5A1 is a protein that in humans is encoded by the ''OR5A1'' gene. Olfactory receptors interact with odorant molecules in the nose, to initiate a neuronal response that triggers the perception of a smell. The olfactory receptor proteins are members of a large family of G-protein-coupled receptors (GPCR) arising from single coding-exon genes. Olfactory receptors share a 7-transmembrane domain structure with many neurotransmitter and hormone receptors and are responsible for the recognition and G protein-mediated transduction of odorant signals. The olfactory receptor gene family is the largest in the genome. The nomenclature assigned to the olfactory receptor genes and proteins for this organism is independent of other organisms. Genetic differences A single-nucleotide polymorphism in the OR5A1 receptor (rs6591536) causes very significant differences in the odor perception of beta-ionone, both in sensitivity and also in subjective quality. Individuals who contain a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta-ionone
The ionones are a series of closely related chemical substances that are part of a group of compounds known as rose ketones, which also includes damascones and damascenones. Ionones are aroma compounds found in a variety of essential oils, including rose oil. β-Ionone is a significant contributor to the aroma of roses, despite its relatively low concentration, and is an important fragrance chemical used in perfumery. The ionones are derived from the degradation of carotenoids. The combination of Alpha and beta carbon, α-ionone and β-ionone is characteristic of the scent of Violet (plant) , violets and used with other components in perfumery and flavouring to recreate their scent. The carotenes alpha-carotene , α-carotene, beta-carotene , β-carotene, gamma-carotene , γ-carotene, and the xanthophyll β-cryptoxanthin, can all be metabolized to β-ionone, and thus have vitamin A activity because they can be converted by plant-eating animals to retinol and retinal. Caroteno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-nucleotide Polymorphism
In genetics, a single-nucleotide polymorphism (SNP ; plural SNPs ) is a germline substitution of a single nucleotide at a specific position in the genome. Although certain definitions require the substitution to be present in a sufficiently large fraction of the population (e.g. 1% or more), many publications do not apply such a frequency threshold. For example, at a specific base position in the human genome, the G nucleotide may appear in most individuals, but in a minority of individuals, the position is occupied by an A. This means that there is a SNP at this specific position, and the two possible nucleotide variations – G or A – are said to be the alleles for this specific position. SNPs pinpoint differences in our susceptibility to a wide range of diseases, for example age-related macular degeneration (a common SNP in the CFH gene is associated with increased risk of the disease) or nonalcoholic fatty liver disease (a SNP in the PNPLA3 gene is associated with inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allele
An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chromosomal or genomic location of a gene or any other genetic element is called a locus (plural: loci) and alternative DNA sequences at a locus are called alleles." The simplest alleles are single nucleotide polymorphisms (SNP). but they can also be insertions and deletions of up to several thousand base pairs. Popular definitions of 'allele' typically refer only to different alleles within genes. For example, the ABO blood grouping is controlled by the ABO gene, which has six common alleles (variants). In population genetics, nearly every living human's phenotype for the ABO gene is some combination of just these six alleles. Most alleles observed result in little or no change in the function of the gene product it codes for. However, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homozygous
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal sex-determination system. If both alleles of a diploid organism are the same, the organism is homozygous at that locus. If they are different, the organism is heterozygous at that locus. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygous. The DNA sequence of a gene often varies from one individual to another. These gene variants are called alleles. While some gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olfactory Receptor
Olfactory receptors (ORs), also known as odorant receptors, are chemoreceptors expressed in the cell membranes of olfactory receptor neurons and are responsible for the detection of odorants (for example, compounds that have an odor) which give rise to the sense of smell. Activated olfactory receptors trigger nerve impulses which transmit information about odor to the brain. These receptors are members of the class A rhodopsin-like family of G protein-coupled receptors (GPCRs). The olfactory receptors form a multigene family consisting of around 800 genes in humans and 1400 genes in mice. Expression In vertebrates, the olfactory receptors are located in both the cilia and synapses of the olfactory sensory neurons and in the epithelium of the human airway. In insects, olfactory receptors are located on the antennae and other chemosensory organs. Sperm cells also express odor receptors, which are thought to be involved in chemotaxis to find the egg cell. Mechanism Rat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
