Explain the need of living organisms for nutrients?

Answer 1

Every living organism needs nutrients to grow and carry out essential life functions.

Like water, nutrients are passed between organisms and the environment through biogeochemical cycles.

Answer 2

The functioning of the organism depends on specialized cells constituting the organs.

To perform their functions and renew themselves, cells need material and energy. Exchanges between the organism and the external environment make it possible to meet these needs and eliminate the waste produced.

Digestion and absorption ensure cells from food.

During digestion, the fragmentation of large molecules of various types (carbohydrates, proteins, lipids) contained in food results in a reduced number of small and non-specific types of molecules. This simplification is carried out under the action of digestive enzymes.

At the end of digestion, we find in the small intestine:

Small molecules resulting or not from molecular simplification - glucose, amino acids, fatty acids, water, vitamins - and ions: these are the nutrients.

Large, undigested molecules like cellulose.

Nutrients are absorbed in the small intestine, the wall of which exhibits characteristics that promote their passage from the intestinal cavity into the blood and lymph.

During a set of chemical reactions, the cell uses nutrients on the one hand with oxygen to release energy, on the other hand to produce new molecules.

The energy released by the use of nutrients in the presence of oxygen is partly consumed for cellular activity, partly dissipated in the form of heat.

According to their genetic information, by using energy, cells produce, from nutrients, new molecules necessary for their functioning and renewal: this is assimilation.

All cellular reactions produce water and waste products - urea, uric acid, carbon dioxide.

Blood and lymph carry the nutrients and oxygen needed by cells, and the waste produced by their activity. Exchanges with cells take place through the lymph.

Blood is made up of fluid, plasma and cells, red blood cells and leukocytes. The plasma and the lymph, formed from it, constitute the interior environment.

The dioxygen is taken from the external environment at the exchange surface of the pulmonary alveoli. It is transported, for the most part, reversibly combined with the hemoglobin contained in the red blood cells.

The nutrients, taken in at the level of the intestinal wall, are transported by the plasma, and by the lymph which circulates in the lymphatic vessels.

The waste produced by cellular activity is transported mainly by the plasma via the lymph and rejected into the external environment:

Carbon dioxide at the pulmonary exchange surface;

Urea and uric acid through the urinary tract, in the form of urine produced from plasma in the kidneys, richly irrigated organs.

The cells are bathed in lymph, an intermediary for their exchanges with the blood.

Knowing the nutritional needs (energy and matter) makes it possible to define a diet that avoids excess and deficiency.

The daily food ration corresponds to the quantity of food necessary for the functioning and the maintenance of the organism in a given situation.

The regular intake of meals and the balance between the categories of foods consumed characterize a rational diet.

The qualitative and quantitative needs can be satisfied by a variety of eating behaviors, depending on tastes, cultural habits and available foods.

Food excess, particularly in sugars and fats can affect health (obesity, Diabetes, cardiovascular diseases).

Deficiencies in certain nutrients: vitamins, mineral ions, amino acids, are responsible for nutritional diseases.

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Answer 3

because is the power source that enables the body to function properly and keeps it healthy

Answer 4

yes, all organisms.