Category: P

The addition of a sequence of polyadenylic acid to the 3′ end of a eucaryotic mRNA after its transcription (post-transcriptional). The addition of a sequence of polyadenylic acid to the 5′ end of a eukaryotic RNA after its transcription.  

A form of chromatography in which molecules are separated on the basis of size and charge. The stationary phase (the polyacrylamide gel) is a polymerized version of acrylamide monomers. The gel looks and feels like Jello™. On a molecular basis it consists of an intertwined and cross-linked mesh of polyacrylamide strings. As can be imaged,…

A “sieving” gel, that is used in electrophoresis.  

Having to do with the one way or unidirectional ity of gene transcription in an operon unit. That is, the region near the operator is always transcribed before the more distant regions. By analogy, transcription begins at the left end of an operon unit and proceeds (reads, transcribes) toward the right end of the operon…

The degree to which an atom or molecule bears an electrical charge or a partial electrical charge. In general, the more polar (i.e., separation or partial separation of charge) a molecule is, the more hydrophilic (“water loving”) it is. Polarity results from an uneven distribution of electrons between the atoms comprising a molecule.  

An instrument used for measuring the degree of rotation of plane-polarized light by an optically active compound/solution. An instrument for measuring amount of polarization of fight or rotation of polarized fight,  

A mutation in one gene which, because transcription occurs only in one direction, reduces the expression of subsequent genes in the same transcription unit further down the line.  

A molecule in which the centers of positive and negative (electrical) charge do not coincide, so that one end of the molecule carries a positive (or partial positive) charge and the other end a negative (or partial negative) charge.  

A hydrophilic (“water loving”) portion of a molecule; it may carry an electrical charge. A group that “likes” to be in the presence of water molecules or other polar compounds.  

A mutation consisting of a change of only one nucleotide in a DNA molecule. A change in only one nucleotide in the DNA sequence of a gene. Frame-shift, conservative, non-conservative, missense, nonsense, and silent mutations are examples of point mutations.