In this video we discuss the structure of protein and the structure of amino acids. We cover how amino acids link together to form proteins.
All Proteins contain 4 elements, carbon, hydrogen, oxygen and nitrogen, however, some proteins contain phosphorus, sulfur, iron, zinc, magnesium and other trace metals. Proteins are giant macro molecules that are made up of amino acid building blocks. Amino acids can link together to form long chains, typically a protein consists of 100 or more amino acids linked together.
There are 20 different standard amino acids that your body requires for healthy function. These amino acids are often classified as essential and non-essential amino acids.
Nonessential amino acids are amino acids that our bodies can produce even if we don’t get them from the food we eat. There are 11 non-essential amino acids (list). Essential amino acids cannot be made by the body, so, they must come from foods we eat. There are 9 essential amino acids.
The basic structure of amino acids is that they consist of a alpha carbon, a carboxyl group, which is a carbon, oxygen, hydrogen, hydrogen group, a lone hydrogen atom, an amino group, which is a nitrogen, hydrogen, hydrogen group, and a side chain or functional group, which is often referred to as an R-group. The formation of the side chain is what makes amino acids different from one another.
On the screen is the structural formulas for all 20 of the standard amino acids along with the amino acid selenocysteine, as some sources list it as a 21st standard amino acid. As you can see, they all have the same chemical backbone, and the only difference is their unique functional R group.
These functional R groups of have chemical characteristics that allow amino acids to be organized into groups.
Here we have the non polar amino acids, non polar meaning the electrons are shared equally in the molecule, these are hydrophobic, so they tend to be repelled from water.
Here are the polar amino acids; these molecules can have interactions with other polar amino acids and with water molecules.
Here are the charged amino acids, since they are charged, an ionic bond can form between an R group with a negative charge and an R group with a positive charge.
And here are some amino acids that are considered to have unique structures.
As was stated earlier, amino acids can link together to form long chains, there is an almost infinite number of different variations of chains that can be formed from amino acids. Each chain can have different characteristics with different chemical properties.
When 2 amino acids join together they form what is called a peptide bond. A peptide bond is when the carboxyl or carbon, oxygen, hydrogen, hydrogen group of one amino acid bonds with the amino nitrogen, hydrogen, hydrogen group of another amino acid, as you can see here (on screen).
This is done through a dehydration synthesis reaction, as the amino group involved in the bond loses a hydrogen atom, and the carboxyl group involved in the bond loses an oxygen and hydrogen. So, the peptide bonding results in the release of a water h2o molecule. More amino acids can link in, again releasing water molecules, and form what is called a polypeptide chain.
As you can see in this polypeptide chain, at one end, an amino group remains, called the N terminal, and at the other end a carboxyl group remains, the C terminal. Typically a protein consists of 100 or more amino acids linked together. Some proteins are single polypeptide chains, and other proteins have polypeptide chains linked together.
Individual amino acids can also be released from a peptide chain, by the decomposition reaction hydrolysis. In hydrolysis, a water molecule is added, breaking the peptide bond and freeing up amino acids.
So, amino acids link together in a variety of sequences to form different types of proteins. Some of these proteins serve as enzymes, which help speed up metabolic reactions in the body, some serve as hormones and help regulate certain functions in the body, some proteins help form the structure of various tissues in the body, these are just a few of the many, many functions that proteins have in the body.