Table of Contents
- Definition of Fats
- Understanding Fat Structure
- Types of Fats
- Function of Fats in the Body
- Lesson Summary
Within the studies of biology and nutrition, there are a few large molecules or polymers called macromolecules that perform biological, nutritional, and cellular functions for the organisms that are composed of them. Some macromolecules are the macronutrients that make up the human diet, hence the nutritional phrase of "counting one's macros." Each of these polymers is made up of their own subsequent monomers or smaller molecules bonded together. Fats are a subgroup of the macromolecules or polymers called lipids. Lipids are made up of the monomers fatty acids and glycerol. Lipids and their monomers are composed of the chemical elements carbon, hydrogen, and oxygen. Fats provide many functions for the human body and its cells. Additionally, fats can be broken up into their own categories where different kinds of fats are composed of different kinds of fatty acids.
The macromolecule lipid is structured in varying ways. Fats belong to the subgroup of lipids called triglycerides, tri- meaning "three," and glyceride being derived from "glycerol." Triglyceride or fat structure is composed of three chains of fatty acids bonded to glycerol. Triglyceride molecules vary depending on the kind of fatty acid chains that are bonded to glycerol.
Looking at the triglyceride molecule, glycerol (left side) is composed of three hydroxyl groups or negatively charged anions composed of one hydrogen and one oxygen atom. Fatty acids (three horizontal chains to the right) vary in their molecular structure. Each type of fatty acid is composed of a carboxylic acid which is made up of a carbon atom double-bonded to an oxygen atom and a hydroxide molecule (oxygen and hydrogen). The carboxylic acid bonds to a long aliphatic chain of carbon atoms bonded with varying amounts of hydrogen at different sides or angles. The aliphatic chains can either be saturated and joined together with single bonds, or unsaturated and joined together with double or triple bonds.
Fats or triglycerides vary in their molecular structure. Fats can either be saturated or unsaturated depending on whether the chains of carbon within fatty acid chains are single bonded or double bonded. Additionally, unsaturated fats can either be polyunsaturated or monounsaturated.
Saturated fats are composed of fatty acid chains that contain single bonds between their carbon atoms, meaning that they are bonded through the sharing of a single pair of electrons. Saturated fats are contained in significant quantities in animal products like whole milk, yogurt, cheese, butter, and ice cream. These kinds of fats tend to be solid at room temperature. Although considered the "bad" fat, saturated fatty acids do perform biological functions for humans such as hormone production and the biochemical process of palmitoylation where the human body uses saturated fatty acids like palmitic acid to stabilize other biological processes. Additionally, they are found to make up parts of cell membranes and provide a padded surrounding for organ tissues.
Unsaturated fats are made up of fatty acid chains that contain double bonds between their carbon atoms, where carbon atoms are bonded through the sharing of two electron pairs. Polyunsaturated fats contain more than one instance of a double bond in their chains, while monounsaturated fats contain only one double bond. Unsaturated fats tend to be liquids at room temperature. These fats are common sources of the dietary essential fatty acids alpha-linolenic acid and linoleic acid which cannot be synthesized within the human body. However, essential fatty acids can be used by the body to synthesize other lipids the body needs. Therefore, unsaturated fats are largely considered the "good" fats. Foods that are high in unsaturated fats are eggs, fish, olive oil, poultry, avocados, and nuts.
Fats are one of the macronutrients for the human body. They provide functions in certain biochemical processes and compose important structures within cells. Triglycerides or fats serve the following primary and secondary functions within the human body:
Cholesterol is another kind of lipid that belongs to the category sterol. Cholesterol is biosynthesized by cells using other lipids like fats. Cholesterol is produced in high quantities by the human body for the purpose and uses within cell membranes, intercellular transport, cell signaling, and for the biosynthesis of steroid hormones and vitamin D.
Saturated and unsaturated fats are often used by the body to synthesize cholesterol. Though cholesterol is necessary for the human body, it has been associated with cardiovascular disease. Diets that are high in saturated fats have been associated with the body synthesizing more low-density lipoprotein or "bad" cholesterol. Whereas the consumption of more unsaturated fats has been associated with lower ratios of "bad" cholesterol (LDL) to "good" cholesterol, or high-density lipoprotein (HDL).
Fats, or triglycerides, belong to a category of macromolecules called lipids. Fats are polymers that are made up of certain smaller molecules or monomers bonded together. Fats are composed of a certain structure of glycerol and varying fatty acids. The structure of fats can vary and therefore fats can be subdivided into further categories such as saturated and unsaturated. Fats all contain a glycerol molecule that can bond to three chains of fatty acids, hence the name "triglycerides." However, the kinds of fatty acids that are bonded to glycerol determine the kind and function of the fat. Saturated fat is composed of fatty acid chains that are made up of chains of carbon that are single bonded together. Whereas unsaturated fatty acid chains contain double bonds of carbon. Unsaturated fats can also vary in their number of instances of double bonds. Monounsaturated fats contain fatty acid chains that only have one instance of a double-bonded carbon atom, and polyunsaturated fatty acids will have two or more instances of double bonds.
Fats provide many functions for the body. Depending on the type, fats provide organisms with insulation, padding, and long-term energy storage as secondary functions. At the cellular level, fats provide primary functions of composing cell membranes, storing vitamins, filtering out toxins, the production of hormones, and regulating and stabilizing other biochemical processes. Additionally, fat is one of the main sources for synthesizing other lipids within the body like cholesterol.
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Fat is made up of the monomers glycerol and fatty acid. Fat functions as insulation, padding, and long-term energy storage for organisms. Additionally, fats make up main components of cell membranes, and are responsible for storage of vitamins, filtering toxins, and the synthesis of important hormones.
Fats consist of the monomers or smaller molecules, glycerol and fatty acid. These molecules are composed of the chemical elements hydrogen, carbon, and oxygen.
The basic structure of a fatty acid is a chain of carbon atoms bonded together that have branching bonds with hydrogen. Fatty acids can consist of carbon atoms bonded in single bonds, as a saturated fatty acid, or double bonds in unsaturated fatty acids.
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