Lysosome

Jump to navigation Jump to search
Various organelles labeled. The lysosome is labeled in the upper left.
Schematic of typical animal cell, showing subcellular components. Organelles: (1) nucleolus (2) nucleus (3) ribosome (4) vesicle (5) rough endoplasmic reticulum (ER) (6) Golgi apparatus (7) Cytoskeleton (8) smooth Endoplasmic reticulum (9) mitochondria (10) vacuole (11) cytoplasm (12) lysosome (13) centrioles

WikiDoc Resources for Lysosome

Articles

Most recent articles on Lysosome

Most cited articles on Lysosome

Review articles on Lysosome

Articles on Lysosome in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Lysosome

Images of Lysosome

Photos of Lysosome

Podcasts & MP3s on Lysosome

Videos on Lysosome

Evidence Based Medicine

Cochrane Collaboration on Lysosome

Bandolier on Lysosome

TRIP on Lysosome

Clinical Trials

Ongoing Trials on Lysosome at Clinical Trials.gov

Trial results on Lysosome

Clinical Trials on Lysosome at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Lysosome

NICE Guidance on Lysosome

NHS PRODIGY Guidance

FDA on Lysosome

CDC on Lysosome

Books

Books on Lysosome

News

Lysosome in the news

Be alerted to news on Lysosome

News trends on Lysosome

Commentary

Blogs on Lysosome

Definitions

Definitions of Lysosome

Patient Resources / Community

Patient resources on Lysosome

Discussion groups on Lysosome

Patient Handouts on Lysosome

Directions to Hospitals Treating Lysosome

Risk calculators and risk factors for Lysosome

Healthcare Provider Resources

Symptoms of Lysosome

Causes & Risk Factors for Lysosome

Diagnostic studies for Lysosome

Treatment of Lysosome

Continuing Medical Education (CME)

CME Programs on Lysosome

International

Lysosome en Espanol

Lysosome en Francais

Business

Lysosome in the Marketplace

Patents on Lysosome

Experimental / Informatics

List of terms related to Lysosome

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]


Overview

Lysosomes are organelles that contain digestive enzymes (acid hydrolases). They digest excess or worn out organelles, food particles, and engulfed viruses or bacteria. The membrane surrounding a lysosome prevents the digestive enzymes inside from destroying the cell. Lysosomes fuse with vacuoles and dispense their enzymes into the vacuoles, digesting their contents. They are built in the Golgi apparatus. The name lysosome derives from the Greek words lysis, which means dissolution or destruction, and soma, which means body. They are frequently nicknamed "suicide-bags" or "suicide-sacs" by cell biologists due to their role in autolysis. Lysosomes were discovered by the Belgian cytologist Christian de Duve in 1949.

Acidic environment

At pH 4.8, the interior of the lysosomes is more acidic than the cytosol (pH 7.2). The lysosome single membrane stabilizes the low pH by pumping in protons (H+) from the cytosol via proton pumps and chloride ion channels. The membrane also protects the cytosol, and therefore the rest of the cell, from the degradative enzymes within the lysosome. For this reason, should a lysosome's acid hydrolases leak into the cytosol, their potential to damage the cell will be reduced, because they will not be at their optimum pH!

Enzymes

Some important enzymes in these are:

Lysosomal enzymes are synthesized in the cytosol and the endoplasmic reticulum, where they receive a mannose-6-phosphate tag that targets them for the lysosome. Aberrant lysosomal targeting causes inclusion-cell disease, whereby enzymes do not properly reach the lysosome, resulting in accumulation of waste within these organelles.

Functions

The lysosomes are used for the digestion of macromolecules from phagocytosis (ingestion of other dying cells or larger extracellular material), endocytosis (where receptor proteins are recycled from the cell surface), and autophagy (where old or unneeded organelles or proteins, or microbes which have invaded the cytoplasm are delivered to the lysosome). Autophagy may also lead to autophagic cell death, a form of programmed self-destruction, or autolysis, of the cell, which means that the cell is digesting itself.

Other functions include digesting foreign bacteria (or other forms of waste) that invade a cell and helping repair damage to the plasma membrane by serving as a membrane patch, sealing the wound. Lysosomes also do much of the cellular digestion required to digest tails of tadpoles and to remove the web from the fingers of a 3-6 month old fetus. This process of programmed cell death is called apoptosis.[1]

Clinical relevance

There are a number of illnesses that are caused by the malfunction of the lysosomes or one of their digestive proteins, e.g., Tay-Sachs disease, or Pompe's disease. These are caused by a defective or missing digestive protein, which leads to the accumulation of substrates within the cell, impairing metabolism.

Broadly, these can be classified as mucopolysaccharidoses, GM2 gangliosidoses, lipid storage disorders, glycoproteinoses, mucolipidoses, or leukodystrophies.

Structure

Small round structures that contain chemicals.

Additional images

References

  1. Mader, Sylvia. (2007). Biology 9th ed. McGraw Hill. New York. ISBN 978-0072464634

External links


Template:Organelles

ar:جسيمات حالة ca:Lisosoma cs:Lyzozom da:Lysosom de:Lysosom el:Λυσόσωμα eo:Lizosomo gl:Lisosoma ko:리소좀 hr:Lizosom it:Lisosoma he:ליזוזום lb:Lysosom lt:Lizosomos mk:Лизозом nl:Lysosoom no:Lysosom sk:Lyzozóm sl:Lizosom sr:Лизозом sh:Lizozom fi:Lysosomi sv:Lysosom uk:Лізосома


Template:WikiDoc Sources