Cells
Structures & Function
Cells 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 walk the Earth!
The main portion of 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 membrane. 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 body, there are many parts in a cell. In order to survive, cells rely on tiny specialized parts within them. These special "mini-cells" help the cell 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 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 healty 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.
Stem Cell Reaerch
Importance of Stem Cells
One of the most controversial in the scientific community concerns stem cell research from embryos. What are stem cells and why are they so important? Embryonic stem cell research is believed to hold the key for better treatments and possible cures for some serious illnesses. Stem cells are primitive cells. There are over 3000 distinct types of cells in the human body , but stem cells are the only types that can be grown into other kinds of cells. This is very useful for scientists and doctors. They hope to grow stem cells to regrow damaged tissue or treat injuries. Using mice, scientists have successfully cured Parkinson's disease, damaged nerve tissue, and even diabetes. Now the challenge is to do the same with humans.
Use Of Stem Cells
For example, when a person is in a serious fire, they will likely have very bad burns. Their skin will be scarrd for the rest of their life. Using stem cells, scientists think they can grow new healthy skin cells. Then they could transplant this new skin onto the burn victim. If there is damage to a person's liver from heavy alcohol use, new liver cells could be grown.
The Controversy
In Order to obtain enough stem cells from embryos, scientists often get them from fertility clinics. These are medical clinics that help women become pregnant. Sometimes, embryos are thrown in the garbage by the clinic. The embryos can be used in research laboratories. But these embryos (usually 4~5 days old) need to be killed to access the stem cells inside. This bothers many people. Some people with strong Christian beliefs have been very out spoken against stem cell research. They argue that a single embryonic stem cell is the most basic form of human life. It is like ending the life of a human being. Due to this controversial ethical issue, in 2001, the U.S. goverment banned giving federal research funding to scientists conducting embryonic stem cell research. If scientists can find another way to get stem cells (other than by killing the embryos), they might be able to cure many of the diseases today.