In
Journey into the Cell, we looked at the structure of the two major types of cells: prokaryotic and eukaryotic cells. Now we turn our attention to the "digester" of a eukaryotic cell, the
lysosome.
What are lysosomes?
Lysosomes are membranous sacs of enzymes. These enzymes are typically
hydrolytic and can digest cellular macromolecules.
They are made by the
endoplasmic reticulum and
Golgi complex. Lysosomes are more than likely formed by budding from the "shipping" department of a Golgi complex.
What are some distinguishing characteristics?
Lysosomes contain various hydrolytic enzymes that are capable of digesting
nucleic acids,
polysaccharides,
fats, and
proteins.
The inside of a lysosome is acidic. Since the enzymes work best in an acidic environment, if a lysosome's integrity is compromised, the enzymes would not be very harmful in the neutral cytosol.
Lysosome Function
Lysosomes have various roles. They are active in recycling the cell's organic material and in the intracellular digestion of
macromolecules.
In addition, in many organisms, lysosomes are involved in
programmed cell death.
Lysosome Defects
In humans, a variety of inherited conditions can affect lysosomes. These defects are called storage diseases and include
Pompe's disease and
Tay-Sachs disease. People with these disorders are missing one or more of the lysosomal hydrolytic enzymes.
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