Cellular Differenciation and Stem Cells Flashcards
What are stem cells?
Stem cells are unspecialised, somatic cells that have the ability to become specialised cells through cellular differentiation
They reproduce themselves by repeated mitosis and cell division
Definition of cellular differentiation?
Cellular differentiation is where an unspecialised cell develops and becomes altered to have specialised functions and properties.
Describe cellular differentiation and selective gene expression
Every cell contains all the genes that make up all the cells within the organism and all the genes have the potential to be switched on.
During differentiation, genes controlling characteristic features are switched on so that the genes expressed are the ones specific to that type of specialised cell. This is called selective gene expression.
Unnecessary genes are switched off so that the cell only produces the required proteins for that type of specialised cell.
What are the two types of stem cell?
Embryonic stem cells
Tissue stem cells
Describe embryonic stem cells
Embryonic stem cells can differentiate into every cell type used to make up the organism as they are pluripotent.
They don’t self renew naturally but can do so under conditions in a lab.
Describe tissue stem cells
Tissue stem cells are used in adults for growth and repair.
They can differentiate into a limited number of cell types as they are multi potent.
What are unspecialised cells and what are they called in plants and animals?
Unspecialised cells are capable of becoming any kind of cell
Animals: stem cells
Plants: meristematic cells
What are meristems
Plant growth is restricted to to regions of the plant called meristems
This gives plants the ability to regenerate damaged or eaten parts
What are the two types of meristem?
Apical meristems
Lateral meristems
What are apical meristems?
They are found at the tip of the root and shoot adding length to the plant (primary growth)
What are lateral meristems?
They allow the stems to thicken (secondary growth)
What are the zones of the plant stem from top to bottom
Zone of cell division
Zone of elongation
Zone of differentiation
Permanent tissues
Reminder
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