Cells
Structures & Function
Cell are very unique creations. They are the basic unit of living organisms. They perform many functions. Every animal,bird,insect and plant is comprised of millions of tiny cells. Cells are essentially the ''building blocks" of life. Some of the first known cells were formed 1.5 billion years ago. That is long before dinosaurs walked the Earth!
The main portion of all cells is filled with a fluid material. Just like a human body, the interior of the cell contains food, waste material or even extra water. On the outside of all cells is a protective covering called a membane. It is just like the shell of an oyster. Sometimes cells divide in half, forming a new cell. In other words, one cell splits in half and an exact duplicate forms. Now there are two cells. When we are growing as a baby, cell division is responsible for much of our growth.
Nucleus and DNA
Just like the human body, there are many parts in a cell. In order to survive, cells rely on tiny specialized parts within them. There special "mini-cells" help the do certain jobs or functions. The most important "mini-cell" of all is the nucleus. The nucleus is like the air traffic control center at an airport. It controls the functions of everything inside the cell. Inside the nucleus is DNA. DNA can determine millions of factors including your height, eye color, blood type and even your personality.
Immune system
If a person has a common cold, the human body will release antibodies to fight the cold virus. Antibodies are part of our immune system that fights bacteria and viruses that are harmful. These antibodies are made by white blood cells. Sometimes they are called B cells. The unique thing about white blood cells is that they can detect which cells are carrying harmful bacteria and viruses. The more quickly these cells divide, the sooner your body can fight the cold. A strong healthy person's body will have more white blood cells to attack the flu virus or some other illness. But sometimes this attacking process does not happen quickly enough, so we need to go to the doctor to get some medicine.