Cells differentiate and become specialized cells in order to carry out different functions from embryonic stem cells. However, if you're asking how a cell came into existence, that's a very good question, and no body really knows. An interesting thing to know though, is that when you put phospholipids (what the lipid bilayer of cells is made of) into water, they spontaneously form a lyposome. The reason is because it is the most energetically favorable to do so. This means, that if you have enough phospholipids in solution, you naturally have a cell membrane.
The cells become millions of cells in the human body through the process of replication.
When cells differentiate, they become specialized.
The brain is composed of two types of cells, nerve cells and glial cells.
They can be mutated through irradiation.
Stem cells
Cells in cartilage are stimulated to become chondroblasts, which are responsible for secreting extracellular matrix components like collagen and proteoglycans. These cells play a key role in maintaining and repairing cartilage tissue.
There are many ways in which cells become different. They could take the shape of many different kinds of things.
Stem cells can become any cells. Stem cells are generated right after the formation of a newly fertilized egg. They are present in both adult and embryonic body.
Transport
meristematic cells
We call this specialization or differentiation.
Cells are the smallest things make an organism. Different cells have cells have different organelles. The same types of cells become tissues, tissues become organs, organs become organ systems, and organ systems become organisms. I hope this answered your question!