Lysosomes

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Hydrolytic

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Programmed Cell Death

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Invasive Organisms

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Cabohydrate, Lipids & Cytoplasm

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Thay-Sach's Disease

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Lysosomes

lysosomeLysosomes are spherical vesicles found in most eukaryotic cells. They are made of a fatty bilayer membrane. Inside, lysosomes contain over 50 different enzymes that carry out digestion on a variety of substances and pathogens. It is a special vesicle formed by the Golgi apparatus that, once developed, acts as an organelle with important roles in cell metabolism, cell membrane repair, and the cell’s waste disposal system.  The largest lysosomes are 10 times bigger than the smallest ones, and they are scattered throughout the cell.  Lysosomal enzymes are first synthesized in the rough endoplasmic reticulum, and then make their way in vesicles over to the Golgi complex. From there, the lysosomes form.

The enzymes of the lysosome give it the unique ability to act as a floating garbage collector. It swallows dead organelles, debris, and even pathogens that may make their way into the cell, and even some that may be hovering just outside the cell.  In so doing, lysosomes also acquire new enzymes. Using these, coupled with the enzymes that were originally synthesized by the endoplasmic reticulum, lysosomes break down important food for the cell like peptides, nucleic acids, carbohydrates, and lipids.

Because lysosomes are derived from the Golgi apparatus, their structure resembles it and the endoplasmic reticulum.  The two-layer membrane of lysosomes protects the cell’s functioning lysosomesorganelles from being damaged by its powerful enzymes. Even if there is leakage into the cytosol, the acidic lysosomal enzymes and the basic cytosol typically combine to form water, which of course does not harm the cell. After serving their functions, developed and mature lysosomes can be recycled back into the Golgi complex along with the nutrients, enzymes, and proteins they contain. If the lysosomes hold substances the cell means to secrete, they can be absorbed by the cell’s membrane. The membrane then forms a vesicle on the outside and secrets the substances. The membranes of absorbed lysosomes replenish the cell membrane after secretions occur. Without this replenishment, the cell membrane would slowly dissipate.

Summary

Lysosomes are one of the special vesicles that bud off from the Golgi apparatus containing over 50 powerful enzymes and proteins that were first synthesized in the endoplasmic reticulum. While their lipid-based bilayer membranes protect the cell’s functional organelles, lysosomes’ powerful enzymes break down the cell’s food for its use and also act as the cell’s garbage collector by swallowing/absorbing its dead organelles, debris, and pathogens. Upon maturation and after being a functional organelle for some time, the lysosome can be recycled back into the Golgi complex, bringing its nutrients with it, or it can be absorbed by the cell membrane so that a cell membrane-organelle membrane homeostasis can be maintained.

 

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