Tin is a malleable silvery-white metal which takes a high polish. It possesses a highly crystalline structure and is moderately ductile. When a bar of tin is bent, the crystals break, producing a characteristic 'tin cry'. Two or three allotropic forms of tin exist. Gray or a tin has a cubic structure. Upon warming, at 13.2Â°C gray tin changes to white or b tin, which has a tetragonal structure. This transition from the a to the b form is termed the tin pest. A g form may exist between 161Â°C and the melting point.
The particular order of the bases arranged along the sugar-phosphate backbone is called the DNA sequence; the sequence specifies the exact genetic instructions required to create a particular organism with its own unique traits. Each strand of the DNA molecule is held together at its base by a weak bond.
DNA Ligase Defined. DNA ligase is an enzyme that has a very critical role in the process of DNA replication and DNA repair. There are two different things going on when DNA is replicated. Let's revisit this process very briefly.