The Structure of Fat
The lipid macromolecule can take on a number of different structures. Triglycerides are a class of lipids; the prefix tri- means "three" and glyceride is derived from "glycerol," so the term "triglyceride" refers to fats. The basic structure of fat, called a triglyceride, consists of three fatty acid chains bonded to glycerol. There are many different kinds of triglyceride molecules because of the different kinds of fatty acid chains that can be bonded to glycerol.

Functions of fat
It's common knowledge that eating a diet high in cholesterol and other fats can increase the risk of developing a disease. However, there is a minimum amount of fat that our bodies require, and we can't produce this on our own.
The scientific term for fats that our bodies can't produce on their own is "essential fatty acids," and these acids' many functions include storing energy, providing insulation, and protecting our internal organs. They serve as communication links, facilitating the work of proteins. As a result of the chemical reactions they initiate, growth, immune function, reproduction, and other aspects of basic metabolism are under control.

Humans and other animals regulate their energy levels by constantly making, breaking down, storing, and mobilizing fats. Diseases like heart disease and diabetes can develop when there is a breakdown in any one of these processes. For instance, high levels of triglycerides in the blood increase the risk of arterial plaque buildup, which can result in cardiac arrest or a stroke.

Some fats actually aid the body in storing other nutrients. Vitamins A, D, E, and K are referred to as "fat-soluble" vitamins because they are stored in fatty tissues and the liver.

Because fats are involved in so many physiological processes, scientists funded by the National Institutes of Health study them in humans and other organisms to gain insight into both typical and abnormal biology.

Amino acid chains are linked together to form proteins. The amino acid building blocks of the hundreds of thousands of natural proteins are slightly different. A protein's number of amino acids can range from hundreds to thousands. The structure of amino acids is relatively consistent.

Whenever many amino acids join together to form long chains, we refer to the resulting structure as a protein (it is also called a polypeptide because it contains many peptide bonds). There are two main functions for proteins in the human body:
1. Most of the human body's solid tissue comprises structural proteins. The structural proteins keratin and collagen, for instance, make up the bulk of your hair, muscles, tendons, and skin.

2. Second, the human body relies on functional proteins to help it accomplish its many tasks. An example of a functional protein is hemoglobin, which is found in red blood cells and aids in oxygen transportation throughout the body. Muscle contraction is facilitated by the protein myosin, which is found in muscle tissue. Insulin is a protein hormone that controls how much glucose the body stores. Polypeptides belonging to the class of enzymes are considered a subset of the functional proteins. Enzymes are proteins that facilitate biochemical reactions. For instance, the enzyme amylase can be found in both human saliva and the intestines, where it aids in the digestion of starch and the subsequent release of glucose for energy.

It is estimated that the human body contains over a hundred thousand distinct proteins, each of which is constructed from a unique set of 20 amino acids. Various proteins serve various functions in the body, each with its own unique structure. Protein-rich foods (meat, fish, beans, eggs, cheese, etc.) are digested into their component amino acids after the polypeptide chains are cleaved apart in the digestive tract. In a process known as protein synthesis, these amino acids are recombined to create proteins
that are unique to each person.


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