Higher Biology - Unit 1.4

​Unit 1.4

Cellular Differentiation

​Differentiation

• When a cell expresses genes that character​ise a certain type of cell, the cell has become differentiated

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• ​Once a cell has become differentiated it only expresses the genes that produce the proteins characteristic for this type of cell

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• Cells which are differentiated are specialised to carry out a specific function, making them important in a multicellular organism​

Specialised Cells

• Specialisation comes with a cost, that being that specialised cells become unable to make copies of themselv​es

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• Due to this problem, multicellular organisms must mantain unspecialised cells which can replenish these cells when needed​.

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• These cells are called stem cells​

Meristems

• Meristems are the region of unspecialised cells in plants

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• Meristems makes unspecialised cells which can become any specialised cel​l

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• Only found at the tip of the roots and shoots and in between the xylem and phloem

Stem Cells

• The region of unspecialised cells in animals

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• There are 2 types; Embryonic and Tissue (adult)

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• Used theraputically to repair damaged, or diseased organs

Embryonic Stem Cells

• Found in an early embryo, and are able to divide continuously

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• All genes in an embryonic stem cell can be​ expressed, therefore they can give rise to all types of cell

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• They are essential for growth​

Tissue Stem Cells

• Found in mature organisms

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• Their function is to replenish differentiated cells that need to be replaced

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• T​hey are called multipotent, meaning they can only give rise to the limited range of cells of their particular tissue type

Fill in the Blanks

Which 13 letter word best describes a stem cell?

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Name the region of unspecialised cells in plants

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Name the region of unspecialised cells in animals

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Which type of stem cells are found in mature organisms (animals)?

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Which type of stem cells are found in an early embryo

Multiple Choice

Which of the following cells are multipotent?

• Embryonic stem cells

• Tissue stem cells

​List of Terms

Cellular differentiation - The process of specialisation when an undifferentiated cell expresses certain genes fitting of its characteristics

Embryonic stem cell - Stem cell from an embryo that can divide and become any type of cell

Tissue stem cell - Stem cell from tissue that can divide and differentiation to become cells of that tissue

Meristem - The region of unspecialised cells in plants where photosynthesis occurs

Stem cells - The region of unspecialised cells in animals

Multipotent - Refers to Tissue stem cells which can only give rise to a limited range of cells of their particular tissue type

Pluripotent - Refers to Embryonic stem cells which can differentiate into all the cell types​

Fill in the Blanks

The process of specialisation when a undifferentiated cell expresses certain genes fitting of its character

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Stem cell from an embryo that can divide and become any type of cell

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Stem cell from tissue that can divide and differentiation to become cells of that tissue

​END OF KEY AREA