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Home >> Molecular Biology Dictionary >> Allopolyploid - Amino acid
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Allopolyploid
(Gr. allos, other, + polyploidy). A polyploid organism (usually a plant) having multiple sets of chromosomes derived from different species. Hybrids are usually sterile, because they do not have sets of homologous chromosomes and therefore pairing cannot take place.
However, if doubling of the chromosome number occurs in a hybrid derived from two diploid (2n) species, the resulting tetraploid (4n) is a fertile plant, since it contains two sets of homologous chromosome and pairing may occur’ this teteraploid is an allotetraploid
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Allosteric control
See allosteric regulation.
Allosteric regulation.
A catalysis-regulating process in which the binding of a small effector molecule to one site on an enzyme affects the activity at another site.
Allosteric transition
A reversible interaction of a small molecule, resulting in a change in the shape of the protein and a consequent alteration of the interaction of that protein with a third molecule.
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Allotetraploid
An: organism with four genomes derived from hybridization of different species. Usually, in forms that become established, two of the four genomes are from one species and two are from another species. See allopolyploid.
Alloy
a metallic solid or liquid formed from an intimate combination of two or more elements.
Allozygote
A diploid individual that is homozygous, at a locus in which the two genes are not identical by descent from a common ancestor.
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Allozyme
See allosteric enzyme.
Alphalactalbumin
Protein component of milk.
Alternative mRNA splicing
The inclusion or exclusion of different exons to form different mRNA transcripts. See RNA.
Alu
A family of approx. 300 bp repetitive sequences, found dispersed throughout the human genome. Almost any 100 kb human nucleotide sequence will have Alu sequences within it.
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Alu sequences
A family of 300-bp sequences occurring nearly a million times in the human genome.
Amino acid
1. (Gr. Ammon, from the Egyptian sun god, in M. L. used in connection with ammonium salts). An acid containing the group NH2. In particular, any of 20 basic building. blocks of proteins with a free amino (NH2) and a free carboxyl (COOH) group, and having the basic formula NH2 - CR - COOH. According to the side group R, they are subdivided into:
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polar or hydrophilic (serine, threonine, tyrosine, asparagine and glutamine); non-polar or hydrophobic (glycine, alanine, valine, leucine, isoleucine, proline, phenylalanine, tryptophan and cysteine); acidic (aspartic acid and glutamic acid).and basics (lysine, arginine, hystidine). The sequence of amino acids determines the shape, properties and the biological role of a protein. Plants and many micro-organisms can synthesize amino acids from simple inorganic compounds, but animals are unable to synthesize some of them, called essential amino acids, so they must be present in the diet.
2. A functional group which consists of a carbon with a carboxylic acid, "-COOH" and an amine, "-NH2” These compounds are the building blocks for proteins
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