Your cells are the energy converters for your body. ... Each cell has a size and shape that is suited to its job. Cells that do the same job combine together to form body tissue, such as muscle, skin, or bone tissue. Groups of different types of cells make up the organs in your body, such as your heart, liver, or lungs.

Two-thirds of a cell is water, which means that two-thirds of your whole body is water. The rest is a mixture of molecules, mainly proteins, lipids and carbohydrates. Your cells turn the raw materials in the food you eat into the molecules your body needs, using thousands of different chemical reactions.

Why do cells need energy?

Living organisms must take in energy via food, nutrients, or sunlight in order to carry out cellular processes. The transport, synthesis, and breakdown of nutrients and molecules in a cell require the use of energy.

How do cells get damaged?

Harmful molecules are continually bombarding your body. The worst offenders are glucose (a type of sugar), and free radicals, by-products of energy production. Both can damage the proteins, fats and DNA that make up your cells. When you are young, your body is able to repair most of this damage.

How many cells are in the human body?

Scientists concluded that the average human body contains approximately 37.2 trillion cells! Of course, your body will have more or fewer cells than that total, depending upon how your size compares to the average human being, but that's a good starting point for estimating the number of cells in your own body!