How Do Cells Turn Nutrients into Usable Energy? Complex organic food molecules such as sugars, fats, and proteins are rich sources of energy for cells because much of the energy used to form these molecules is literally stored within the chemical bonds that hold them together.

The cell is the smallest structural and functional unit of living organisms, which can exist on its own. Therefore, it is sometimes called the building block of life. Some organisms, such as bacteria or yeast, are unicellular—consisting only of a single cell—while others, for instance, mammalians, are multicellular.

Therefore, cells not only make up living things; they are living things. Cells are found in all plants, animals, and bacteria. Many of the basic structures found inside all types of cells, as well as the way those structures work, fundamentally are very similar, so the cell is said to be the fundamental unit of life.

These most basic human survival needs include food and water, sufficient rest, clothing and shelter, overall health, and reproduction. Maslow states that these basic physiological needs must be addressed before humans move on to the next level of fulfillment.

A traditional list of immediate “basic needs” is food (including water), shelter and clothing. Many modern lists emphasize the minimum level of consumption of “basic needs” of not just food, water, clothing and shelter, but also sanitation, education, and healthcare. Different agencies use different lists.

A need is something thought to be a necessity or essential items required for life. Examples include food, water, and shelter. A want is something unnecessary but desired or items which increase the quality of living. Examples include a car stereo, CD’s, car, and designer clothes.

The primary needs are the basic requirements according to biological demands like oxygen for breathing, water for overcoming thirst, food for living and shelter. The humans cannot live without primary needs.