Lipids provide what kind of energy for the cell

Lipids are a family of organic compounds that are mostly insoluble in water. Composed of fats and oils, lipids are molecules that yield high energy and have a chemical composition mainly of carbon, hydrogen, and oxygen. Lipids perform three primary biological functions within the body: they serve as structural components of cell membranes, function as energy storehouses, and function as important signaling molecules. The three main types of lipids are triacylglycerols also called triglycerides , phospholipids, and sterols.

Triacylglycerols also known as triglycerides make up more than 95 percent of lipids in the diet and are commonly found in fried foods, vegetable oil, butter, whole milk, cheese, cream cheese, and some meats. Naturally occurring triacylglycerols are found in many foods, including avocados, olives, corn, and nuts.

As with most fats, triacylglycerols do not dissolve in water. The terms fats, oils, and triacylglycerols are discretionary and can be used interchangeably. In this chapter when we use the word fat, we are referring to triacylglycerols. Phospholipids make up only about 2 percent of dietary lipids.

They are water-soluble and are found in both plants and animals. In fact, phospholipids are synthesized in the body to form cell and organelle membranes. In blood and body fluids, phospholipids form structures in which fat is enclosed and transported throughout the bloodstream.

Sterols are the least common type of lipid. Cholesterol is perhaps the best well-known sterol. Though cholesterol has a notorious reputation, the body gets only a small amount of its cholesterol through food—the body produces most of it.

Cholesterol is an important component of the cell membrane and is required for the synthesis of sex hormones, vitamin D, and bile salts. Later in this chapter, we will examine each of these lipids in more detail and discover how their different structures function to keep your body working. The excess energy from the food we eat is digested and incorporated into adipose tissue, or fatty tissue.

Most of the energy required by the human body is provided by carbohydrates and lipids. As discussed in Chapter 3 "Carbohydrates" , glucose is stored in the body as glycogen. While glycogen provides a ready source of energy, lipids primarily function as an energy reserve. As you may recall, glycogen is quite bulky with heavy water content, thus the body cannot store too much for long.

Alternatively, fats are packed together tightly without water and store far greater amounts of energy in a reduced space. A fat gram is densely concentrated with energy—it contains more than double the amount of energy than a gram of carbohydrate.

Energy is needed to power the muscles for all the physical work and play an average person or child engages in. Unlike other body cells that can store fat in limited supplies, fat cells are specialized for fat storage and are able to expand almost indefinitely in size.

An overabundance of adipose tissue can result in undue stress on the body and can be detrimental to your health. A serious impact of excess fat is the accumulation of too much cholesterol in the arterial wall, which can thicken the walls of arteries and lead to cardiovascular disease. Thus, while some body fat is critical to our survival and good health, in large quantities it can be a deterrent to maintaining good health.

Triacylglycerols also help the body produce and regulate hormones. For example, adipose tissue secretes the hormone leptin, which regulates appetite. In the reproductive system, fatty acids are required for proper reproductive health; women who lack proper amounts may stop menstruating and become infertile.

Omega-3 and omega-6 essential fatty acids help regulate cholesterol and blood clotting and control inflammation in the joints, tissues, and bloodstream.

Fats also play important functional roles in sustaining nerve impulse transmission, memory storage, and tissue structure. More specifically in the brain, lipids are focal to brain activity in structure and in function.

They help form nerve cell membranes, insulate neurons, and facilitate the signaling of electrical impulses throughout the brain. Figure 4. Lipids are essential for cells to function properly.

Water: an essential element for the human body What happens when the body is dehydrated? How much fluid is lost during sports?

How to replace lost fluids Effective rehydration Nutritional balance essentials for athletes and active people Why do athletes have to eat a lot? Fats: an efficient source of energy Carbohydrates: an efficient energy source Proteins: building blocks of the body The function of BCAAs Branched Chain Amino Acids during sports activities Vitamins and minerals Energy production and B vitamins Nutrients that athletes and active people tend to lack What to eat before and on the day of a game Poor nutritional intake amongst young Japanese women: are changing lifestyles the cause?

Examples of the effects of poor nutrition on health and recommended nutrients The amount of energy required when pregnant or nursing Nutrients to pay special attention to when pregnant or nursing. Thus, while some body fat is critical to our survival and good health, in large quantities it can be a deterrent to maintaining good health. Triglycerides also help the body produce and regulate hormones. For example, adipose tissue secretes the hormone leptin, which regulates appetite.

In the reproductive system, fatty acids are required for proper reproductive health. Women who lack proper amounts may stop menstruating and become infertile. Omega-3 and omega-6 essential fatty acids help regulate cholesterol and blood clotting and control inflammation in the joints, tissues, and bloodstream. Fats also play important functional roles in sustaining nerve impulse transmission, memory storage, and tissue structure. More specifically in the brain, lipids are focal to brain activity in structure and in function.

They help form nerve cell membranes, insulate neurons, and facilitate the signaling of electrical impulses throughout the brain. Did you know that up to 30 percent of body weight is comprised of fat tissue? Some of this is made up of visceral fat or adipose tissue surrounding delicate organs. Vital organs such as the heart, kidneys, and liver are protected by visceral fat. The composition of the brain is outstandingly 60 percent fat, demonstrating the major structural role that fat serves within the body.

You may be most familiar with subcutaneous fat, or fat underneath the skin.