Some mutagenic agents mimic nitrogenous bases and insert themselves into the DNA. This is called a base analog. This changes the normal order in the DNA. If bromouracil, a mutagenic agent, is inserted into the DNA, it acts like a thymine and will pair with an adenine. This will cause a new base pair to be inserted into the DNA. This will then cause a change in the original DNA. Another type of mutation is the frameshift mutation. If a base is inserted or deleted either by chance or due to DNA repair mechanism malfunction in the cell or due to exposure to mutagenic chemicals, this causes a frameshift mutation. The DNA code is translated by RNA into amino acids. Every three bases is a codon or triplet. If one single additional base is added, or deleted, the triplets will shift and will not be translated into the correct amino acid sequence of the protein. This will produce a longer or shorter than normal protein, and possibly one that is not functional.