Coin grading. Coin grading is the process of determining the grade or condition of a coin, one of the key factors in determining its value. A coin's grade is generally determined by five criteria: strike, preservation, luster, color, and attractiveness. Several grading systems have been developed. Certification services professionally grade coins for tiered fees.
DNA is composed of repeating units called nucelotides or nucleotide bases. DNA polymerase is responsible for the process of DNA replication, during which a double-stranded DNA molecule is copied into two identical DNA molecules.NA polymerase / DNAP. DNA polymerase (DNAP) is a type of enzyme that is responsible for forming new copies of DNA, in the form of nucleic acid molecules. Nucleic acids are polymers, which are large molecules made up of smaller, repeating units that are chemically connected to one another.
DNA replication is the process by which DNA makes a copy of itself during cell division. 1  The first step in DNA replication is to âunzipâ the double helix structure of the DNA molecule. The new strand is proofread to make sure there are no mistakes in the new DNA sequence. 2  Finally, an enzyme called DNA ligase seals up the sequence of DNA into two continuous double strands. 3  The result of DNA replication is two DNA molecules consisting of one new and one old chain of nucleotides.