Cell differentiation and specialisation Flashcards
Stem cells
Unspecialised cells that can develop into many different cells under some conditions.
What are the two main properties of stem cells?
Self- renewal- ability to go through several cell cycles without further differentiation
Potency- ability to differentiate into specialised cell types.
Totipotent stem cells
The first cells that form during cell proliferation. All of their genetic material is expressed in the daughter cells formed. They are undifferentiated cells that can later differentiate into any type of cell.
Pluripotent stem cells
only express specific parts of the DNA that are associated with that cell group. They can proliferate into any of the cell types in that group.
Stem cells found in multicellular organisms after birth are called:
Adult stem cells. They are responsible for repair and maintenance of the adult body.
If a cell is specialised..
It needs to be replaced with an equally specialised cell. It is not practical for a multicellular organism to keep a set of specialised cells in case of damage so they have unspecialised cells instead.
Specialised cells..
Have some of their DNA permanently switched off.
What is the hierarchy of multicelular organisms?
cells, tissues, organs and systems
What two classes of molecules re involved in cell differentiation?
transmembrane molecules, which are used for binding cells together and cell signalling, and
gene regulatory proteins, which determine which genes are switched on or off in the cell and therefore determine the cells structure and function.
Tissues
In most organisms, cells are arranged in tissues. They are a group of the same types of cells specialised to perform a specific function. The cells in a tissue are bathed in extracellular fluid.
Organs
An organ is composed of more than one type of tissue, forming a structural and functional unit such as the heart.
System
A system is composed of different organs working together for one main function. Systems are coordinated so they facilitate the supply of nutrients and production/ removal of materials from all cells of the organism.
