PROTEINS Are Macromolecules Made up of Several Building Blocks Called Amino Acids

PROTEINS are macromolecules made up of building blocks called amino acids. The general structure of any amino acid molecule includes a carboxyl group of atoms, an amino group, and a side chain (R-group). The carboxyl group contains one carbon, two oxygen, and one hydrogen atom. The amino group contains one nitrogen atom with two hydrogen atoms attached to it.

The side chains (R-groups) of an amino acid vary depending on the type of amino acid. There are 20 different types of amino acids, and they form long chains called polypeptides that bend and fold in different ways to form a protein. The order in which amino acids “line up” in their chain determines what specific protein they will form.

When you eat foods that contain protein, the digestive juices in your stomach and intestine break down the protein into amino acids. These amino acids can then be reused to make proteins for your own body.

Our body is able to make most of the amino acids we need. However, there are nine amino acids that we are unable to make on our own. Protein from animal sources, such as meat and milk, is called complete, because it contains all nine of these essential amino acids. Most vegetable protein is considered incomplete because it lacks one or more of the essential amino acids. This can be a concern for someone who doesn't eat meat or milk products. But people who eat a vegetarian diet can still get all their essential amino acids by eating a wide variety of protein-rich vegetable foods.

For instance, you can't get all the amino acids you need from peanuts alone, but if you have peanut butter on whole-grain bread, you're set! Likewise, red beans won't give you everything you need, but red beans and rice will do the trick. The good news is that you don't have to eat all the essential amino acids in every meal. As long as you have a variety of protein sources throughout the day, your body will grab what it needs from each meal.

Proteins account for more than 50% of the dry mass of most cells, and they are instrumental in almost everything organisms do. Some proteins, called enzymes, help speed up chemical reactions. Other proteins play a role in structural support, cell-to-cell communication, and defense against foreign substances such as viruses and bacteria.

In humans and other animals, a structural protein called keratin makes up our hair and nails. Actin and myosin are important proteins that form our muscles.

SOME IMPORTANT SOURCES OF PROTEIN ARE:

Beef, poulty, fish, soy beans (used to make tofu), nuts and seeds, peanut butter