Nutrients are chemical substances found in every living thing on Earth. They are necessary to the lives of people, plants, animals, and all other organisms. Nutrients help break down food to give organisms energy. They are used in every process of an organism’s body. Some of the processes are growth (building cells), repair (healing a wound), and maintaining life (breathing).
Plants and other autotrophs absorb nutrients from soil and water. Autotrophs are organisms that can make their own food. The most important nutrients they need are carbon, hydrogen, and oxygen. Other nutrients needed by plants are nitrogen, phosphorous, potassium, calcium, magnesium, and sulfur.
From these basic nutrients, plants and other autotrophs synthesize, or create, their own nutrients, such as sugars. The human body can also synthesize some nutrients, such as amino acids. However, most organisms need nutrients created by autotrophs. People and animals get most of their nutrients from food.
Essential nutrients are nutrients that the human body is unable to synthesize. They must be obtained from food or water. Essential nutrients include carbohydrates, proteins, fats, vitamins, and minerals.
Phospholipid bilayers are critical components of cell membranes. The lipid bilayer acts as a barrier to the passage of molecules and ions into and out of the cell. However, an important function of the cell membrane is to allow selective passage of certain substances into and out of cells.
