2.1.2 Proteins Explained

Key Concepts Related to Proteins

1. Structure of Proteins

Proteins are large, complex molecules made up of amino acids. These amino acids are linked together by peptide bonds to form long chains. The sequence of amino acids in a protein determines its structure and function.

Example: Hemoglobin, a protein found in red blood cells, is composed of four polypeptide chains, each containing a heme group that binds to oxygen.

2. Functions of Proteins

Proteins perform a wide range of functions in the body, including structural support, catalyzing biochemical reactions, immune response, and transportation of molecules. They are essential for growth, repair, and maintenance of tissues.

Example: Enzymes, such as amylase, are proteins that catalyze the breakdown of carbohydrates into simpler sugars, aiding in digestion.

3. Essential and Non-Essential Amino Acids

Amino acids are classified into essential and non-essential categories. Essential amino acids must be obtained from the diet because the body cannot synthesize them, while non-essential amino acids can be produced by the body.

Example: Tryptophan is an essential amino acid that the body needs for the production of serotonin, a neurotransmitter involved in mood regulation.

4. Protein Sources

Proteins are found in various food sources, including animal products like meat, dairy, and eggs, as well as plant-based sources such as legumes, nuts, seeds, and grains. The quality of protein depends on its amino acid profile.

Example: Quinoa is a complete protein, meaning it contains all nine essential amino acids, making it a valuable plant-based protein source.

5. Protein Digestion and Absorption

Proteins are broken down into their constituent amino acids during digestion. This process involves enzymes like pepsin in the stomach and proteases in the small intestine. The amino acids are then absorbed into the bloodstream and transported to cells for various functions.

Example: The protein casein in milk is broken down into smaller peptides and amino acids by digestive enzymes, which are then absorbed and used by the body.

Analogies and Examples

Think of proteins as the building blocks of life, similar to the bricks used to construct a house. Just as bricks provide structural integrity to a building, proteins provide structural support and perform essential functions in the body.

Another analogy is to consider proteins as the workers in a factory. Each worker (protein) has a specific job (function) that contributes to the overall operation of the factory (body). Without these workers, the factory would not function properly.

In summary, understanding the structure, functions, types of amino acids, sources, and digestion of proteins is crucial for a Certified Nutritional Practitioner. By recognizing the importance of proteins in the body, you can better guide individuals towards a diet that supports optimal health and well-being.