The inorganic nutrients include water and mineral salts. They are made up of different chemical elements, but their fundamental component is not carbon.
The water is the most abundant component of living organisms, representing between 65% of the human body. In addition to getting water when we drink it, most foods contain water, such as fruit, vegetables, and milk. Its many functions include the regulation of body temperature, the transport of substances through the body, helps eliminate waste, and is the medium where the chemical reactions of cells take place.
The mineral salts, in solution or precipitated, are necessary for the body. They are found in all foods, but are more abundant in fruits and vegetables. The functions of mineral salts are:
- Regulatory function: they intervene in the chemical reactions of the organism.
- Plastic or structural function: for example, calcium and phosphorus are part of the bones, or fluoride, of the teeth.
The gl úcidos or carbohydrates are the most abundant nutrients in plant foods. Two types are distinguished:
- Simple carbohydrates: they are sweet and are quickly digested and absorbed. They are abundant in fruits and some vegetables. Examples: glucose, fructose , etc.
- Complex carbohydrates: they are not sweet. They are large molecules made up of many simple carbohydrates. Examples: starch, present in potatoes, legumes and cereals, and cellulose, which provides vegetable fiber.
The simplest carbohydrates are the monosaccharides, such as glucose, the fructose and galactose. When two monosaccharides join together they form a disaccharide, such as maltose (glucose-glucose), sucrose (glucose-fructose) and lactose (glucose-galactose). If many (more than ten) glucose molecules come together they form a polysaccharide like cellulose, starch and glycogen.
Carbohydrates have an energetic function. One gram of glucose provides 4 kilocalories. There are also polysaccharides with energy function. The starch serves as an energy reserve in plants and glycogen in animals.
Other carbohydrates have a structural function , such as cellulose, which is part of the cell wall of plant cells. The cellulose can not be attacked by the human digestive system, so it is the major component of dietary fiber, which regulates intestinal transit, increasing stool volume and softening consistency, and promotes the absorption of water and nutrients. The fiber is formed by the rest remains of foods undigested by digestive human, they are not only carbohydrates.
nteractive activity: We prepare for the race.
Interactive activity: Foods rich in vegetable fiber.
Interactive activity: Word search about the different types of nutrients.
The lipids are nutrients type having varied functions:
- Energy function: The most abundant lipids are fats, located in the cells of adipose tissue, forming clusters of fat under the skin and between the organs. One gram of fat provides 9 kilocalories, more than double that of glucose, but since cells only consume glucose, fats have to be transformed into glucose in order to be used.
- Plastic function: some lipids, such as phospholipids and cholesterol, are part of the plasma membrane of cells.
- Regulatory function: other lipids act like vitamins and hormones.
Lipids can contain different types of fatty acids in their composition:
- The fatty acids saturated are present in foods of animal origin and some vegetables (palm and coconut) and are taken in excess, harmful to health.
- The fatty acids unsaturated are present in marine animals and plants, and are better suitable for life.
Interactive activity: Animal and vegetable fats.
The main functions of proteins are:
- Plastic function : proteins are the "building blocks" of our body. They are the main components of the cell structure, and allow the growth or replacement of damaged or worn tissues.
- Regulatory function : some regulate the speed of chemical reactions in our body (enzymes), regulate certain activities (hormones), transport substances (hemoglobin carries oxygen), or protect us from diseases (antibodies).
Activity: Foods rich in protein.
Vitamins are substances of organic origin, with regulatory function, involved in cellular chemical reactions. They are essential for the growth and proper functioning of the body.
Although we need a very small amount of vitamins, their absence or deficit in the diet causes the appearance of deficiency diseases. Although they do not provide any energy, they are necessary for the digestion and use of the other nutrients. Vitamins are altered in light and heat, and are abundant in fresh fruits and vegetables.
Interactive activity: Types of nutrients.
Interactive activity: Nutrients.
Curiosity: Farewell to Super Mouse.
2.2.- Explain the three functions that nutrients perform and name the types of nutrients that carry out each function.
2.3.- List the main organic and inorganic nutrients.
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