List+of+keywords+and+definition+of+keys+terms+of+stem+cell

1. DNA
Deoxyribonucleic acid, a chemical found primarily in the nucleus of cells. DNA carries the instructions or blueprint for making all the structures and materials the body needs to function. DNA consists of both [|genes] and non-gene DNA in between the genes.

2. Stem cell
Cells with the ability to divide for indefinite periods in culture and to give rise to specialized cells.

3. Human embryonic stem cells
Also known as a human pluripotent stem cell, one of the "cells that are self-replicating, are derived from human embryos or human fetal tissue, and are known to develop into cells and tissues of the three primary germ layers. Although human pluripotent stem cell may be derived from embryos or fetal tissue, such stem cells are not themselves embryos.

"Self-replicating" means the cell can divide and to form cells indistinguishable from it. The "three primary germ layers" -- called the ectoderm, mesoderm, and endoderm -- are the primary layers of cells in the embryo from which all tissues and organs develop.



4. **Somatic (adult) stem cells**
A relatively rare undifferentiated cell found in many organs and differentiated tissues with a limited capacity for both self renewal (in the laboratory) and differentiation. Such cells vary in their differentiation capacity, but it is usually limited to cell types in the organ of origin. This is an active area of investigation.

5. Tissue
An aggregate of [|cells] in an [|organism] that have similar [|structure] and [|function]. The fundamental types of [|tissues] in [|animals] are [|epithelial], [|nerve], [|connective], [|muscle], and [|vascular] tissues whereas in [|plants], they are the [|meristematic] ([|apical meristem] and [|cambium]), protective ([|epidermis] and [|cork]), fundamental ([|parenchyma], [|collenchyma] and [|sclerenchyma]) and [|vascular] ([|xylem] and [|phloem]) tissues. Tissues that work in unison to carry out a specific set of functions form an [|organ].

6. Mitosis
The process where a [|single] [|cell] divides resulting in generally two identical [|cells], each containing the same number of [|chromosomes] and genetic content as that of the original [|cell].