Difference Between Stem Cells and Normal Cells

Stem Cells vs Normal Cells
 

Difference between stem cells and normal cells can be explained in terms of their structure and functions. Cell is the basic form of life. From single-celled organisms to very complex multicellular organisms, cell serves as the functional and structural unit. In a multicellular organism, there are different types of cells such as red blood cells, neurons, bone marrow cells, etc. As soon as the fertilization is completed, cells start to divide into millions of cells to form the shape of the organism. There are two major types of cells that are present in these organisms (especially, in mammals). They are stem cells and normal cells (specialized cells). However, in a single celled organism, there is no differentiation. This article will compare stem cells and normal cells by first explaining the structure and functions of each cell.

What are Stem cells?

Stem cells are the cells that can develop into other types of cells, especially during the embryonic period. They are actually undifferentiated typical cells. During the development of an animal, these cells will divide (via mitosis) to produce differentiated cells such as white blood cells, red blood cells, neurons, etc. Two categories of stem cells can be found in our bodies. Stem cells found inside the blastocyst during the embryonic period are known as embryonic stem cells. The other type is called adult stem cells. Embryonic stem cells have the ability to divide rapidly and differentiate into any type of cells present in our bodies. So, these cells are also known as pluripotent stem cells. These cells will give rise to each and every organism present in animals. Adult stem cells lack the pluripotent ability. They are only able to replenish the body by giving rise to particular types of cells. These stem cells are described according to their location in the body as well as the resulting cell type after the differentiation. (Ex: – Stem cells in bone marrow that give rise to red blood cells are called hematopoietic stem cells.) Also, these adult cells have lineages back to the embryonic stem cells via progenitor cells and down to differentiated normal cells.(Ex: – Myeloid lineage).

Difference Between Stem Cells and Normal Cells

There are several places in the body where stem cells are found such as bone marrow, adipose tissue, etc. Stem cells are used in cancer and organ transplant therapies and lot of scientists are involved in these. Normal cells also can be induced to have stem cells abilities.

What are Normal cells?

Normal cells are the cells that have been differentiated to perform a special function in a localized area in the body. Human body contains about 40 trillion cells and almost all of them are normal cells. Every organ is composed of cells. However, the structure and function differ. Normal cells do not have the ability to differentiate into other types. They are simply unable to give rise to another type of cell. But, most of them are able to divide mitotically. You would think that every normal cell can undergo mitosis, but there are cells that do not undergo mitosis (Ex: – neurons). Some will divide by meiosis (Ex: – Egg and Sperm mother cells). Normal cells such as blood cells have a short life span (about 2-3 months) whereas neurons have a longer life span (almost same as the human life). Unlike stem cells, normal cells are found everywhere and the shape is also different. Although every stem cell has a nucleus normal cells like red blood cells do not contain a nucleus.

 Stem Cells vs Normal Cells

Neuron

Normal cells are not as vulnerable as stem cells to develop deadly cancers. That is because all the normal cells are not extensively divided through mitosis. However, if we take the ratios of normal cells to stem cells, the cancerous normal cells are very high, simply because of the number of normal cells are higher.

What is the difference between Stem Cells and Normal Cells?

• Stem cells have the ability to divide whereas normal cells may or may not have the ability to divide.

• All the stem cells have the ability to differentiate into normal cells whereas normal cells usually do not have this ability or the reverse is not true.

• Only function that stem cells do is dividing in order to differentiate into other types of cells whereas normal cells have various functions.

• Stem cells do not undergo meiosis whereas some normal cells do.

• Majority of the cells present in the early embryonic fetus (blastocyst) are mostly stem cells whereas with the development these cells will be outnumbered by normal cells.

• Stem cells lie at the beginning of the cell lineages whereas normal cells always lie at the end of the lineages.

• Life span of a stem cell is generally average when compared to normal cells some of which have shorter and very long life spans.

• Both cells can be cancerous cells, but stem cells have the potency.

• Stem cells are found only in several places whereas normal cells are found everywhere.

• Most of the multicellular organisms have stem cells whereas all the living organisms have normal cells.

 

Images Courtesy:

  1. Stem cell diagram by Mike Jones (CC BY-SA 2.5)
  2. Neuron by BruceBlaus (CC BY 3.0)