When a point mutation results in an inadvertent stop codon, it results in a truncated, and often, nonfunctional protein. This is referred to as a nonsense mutation. A point mutation is caused by a switch of a single base pair in the DNA, which may or may not result in the substitution of an amino acid for another since the genetic code is redundant. 

Histone proteins are highly basic proteins found in the eukaryotic cell nuclei that are integral proteins needed to package DNA tightly inside. They are the chief protein components of chromatin, acting as spools around which the DNA winds and plays an important role in gene regulation. Without histones, the unwound DNA in chromosomes would be very long and difficult to control. 

The effect of a point mutation is not dependent on the amino acid—the amino acid's selection is entirely independent of its structure. The amino acid selection during translation depends only on the three base-pair codon read by the ribosome. For example, the start codon—AUG—recruits methionine. If a frameshift mutation lead to UGG as the codon instead, tryptophan would be recruited. No single amino acid is more likely to be incorporated after a point mutation.

The degeneracy of the genetic code is a major concept relating to protein synthesis. This concept states that each codon codes for a single amino acid, but that an amino acid can have more than one codon. If each three-base codon corresponded to a different amino acid, 64 amino acids would be produced in the body. Instead, most amino acids are coded for by multiple codons; for example, lysine corresponds to both AAA and AAG. This concept is especially important with regard to mutations. If an AAA codon undergoes a point mutation to become an AAG codon, the same amino acid will be produced, and the organism will be unharmed.

Amino acids consist of an amine, a carboxylic acid, a hydrogen atom and a side chain (often simply referred to as an “R group”). Differences between these side chains are what differentiate amino acids from one another. These four components are bound to a central carbon atom, giving each amino acid a stereocenter. Amino acids form peptide bonds through condensation reactions between the carboxyl group of one residue and the amino group of another.

Peptide bonds are the uniquely named form of covalent bonds that hold together amino acids. These bonds are formed when the carboxylic acid of one amino acids reacts with the amino group of another amino acid. The result is a peptide polymer, known as a polypeptide, and a water molecule.

Glycosidic linkages are seen in sugars, and are used to bind monosaccharides. Hydrogen and ionic bonds are more general intermolecular forces. Hydrogen bonding helps shape the secondary and tertiary structure of proteins, but does not help in the formation of an amino acid chain.

The amino acids, as denoted by the name, contain amino and carboxyl groups. Each amino acid has the amine group connected to a central carbon, which is then connected to a carboxyl group.

Amino acids may contain R-groups on the central carbon, and all amino acids have a specific R-group except for glycine, which is the simplest amino acid. Glycine is bound to an extra hydrogen atom in place of an R-group. Only methionine can start a protein structure; methionine is coded by the start codon on an mRNA sequence. Some amino acids are capable of forming alpha-helices, while others are capable of disrupting and breaking alpha-helices. Proline, for example, frequently disrupts this secondary structure. Each protein is coded by a specific sequence of amino acids; not all proteins will contain every amino acid.

The number of codons can be found by raising the number of nitrogenous bases to the power of the codon length. In the genetic code, there are four bases and codons are three bases in length.

If codons were four bases in length, then the number of possible bases would be raised to the fourth power.

Every amino acid has a central carbon with an amino terminus and a carboxyl terminus. There is also a hydrogen attached to the central carbon. The last substituent varies between amino acids and determines how the particular amino acid will be used in proteins. This variable group is known as the "R-group." Only one amino acid, alanine, has a methyl group attached in the "R-group" position.

Amino acids are compounds that make up proteins and polypeptide chains. They are made up of an amine group , a carboxylic acid group , and a variable side chain. The amine group is called the “N terminus” and the carboxylic acid group is called the “C terminus”. The N terminus of one amino acid and the C terminus of another amino acid can form a peptide bond through a condensation reaction.