Cell surface membrane is made of two layers of phospholipids
It is embedded with proteins, such as recptors on the outer surface
FUNCTION
Separates the contents of the cell from its external environment
Regulates the movement of substances in to and out of the cell
Most organelles inside the cell are surrounded by their own membrane which enable separate compartments to be formed where specialist reactions take place
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Nucleus
STRUCTURE
The nucleus is a large, round organelle
It is surrounded by a double membrane called the nuclear envelope
The nuclear envelope contains nuclear pores to allow exchange of materials between nucleus and cytoplasm
DNA is found in the nucleus
It contains a dark staining region called nucleolus which produces ribosomes
FUNCTION
Contains the cells DNA
Controls activities of the cell
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Mitrochondrion
STRUCTURE
They are an oval shape
They have a double membrane
Inner membrane is highly folded in to cristae - increase surface ares
Matrix is a viscous liquid that contains enzymes
FUNCTION
Some reactions of aerobic respiration occur
They are the "power houses" of the cell - producing energy in the form of ATP
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Ribosomes
STRUCTURE
Consist of two subunits; one large and one small
Subunits made up of protein and ribosomal RNA
Can be found floating free or attached to endoplasmic reticulum
FUNCTION
The site of protein synthesis
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Endoplasmic Reticulum (ER)
STRUCTURE
Large network of membranes
There are two types
Rough endoplasmic reticulum (RER) - covered with ribosomes
Smooth endoplasmic reticulum (SER) - does not have ribosomes
FUNCTION
Rough endoplasmic reticulum - transports the proteins synthesised at the ribosomes
Smooth enodplasmic reticulum - produces and transports lipids
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Golgi Apparatus (also known as Golgi body)
STRUCTURE
Stack of flattened, membrane bound sacks
Smaller vesicles around it
FUNCTION
Transports and chemically modifes the substances in it
Produces lysosomes
Cells involved with secretion contain large amounts of Golgi apparatus e.g. cells of the pancreas which secrete digestive enzymes
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Lysosome
STRUCTURE
Sac consisting of a single membrane which contains digestive membranes
Enzymes have to be kept apart from rest of cell or they would destroy it
Contents are acidic and enzymes have a low optimum pH
FUNCTION
Breaks down unwanted molecules and structures inside the cell
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