✦✦✦✦ LYSOSOMES ✦✦✦✦

DEFINITION; 

➤LYSOSOMES ARE CYTOPLASMIC ORGANELLES AND ARE DIFFERENT FROM

OTHER DUE TO THEIR MORPHOLOGY.

DISCOVERED BY;

➤THESE WERE ISOLATED AS A SEPARATE COMPONENT FOR THE FIRST TIME

 BY DE DUVE (1949).

lysosomes



MEANINGS;

➤LYSOSOMES (LYSO=SPLITTING; SOMA=BODY) ARE FOUND IN MOST

EUKARYOTIC CELLS.

lysosome function
 

FUNCTION;

➤ANY FOREIGN OBJECT THAT GAINS ENTRY INTO THE CELL IS IMMEDIATELY

ENGULFED BY THE LYSOSOMES AND IS COMPLETELY BROKEN INTO

SIMPLE DIGESTIBLE PIECES. 

THE PROCESS IS KNOWN AS PHAGOCYTOSIS ( EATING PROCESS OF A CELL). 

MOSTLY FOUND;

➤THEY ARE MOST ABUNDANT IN THOSE ANIMAL CELLS WHICH EXHIBIT

PHAGOCYTIC ACTIVITY.

what are lysosomes

 

BOUNDED BY;

➤THEY ARE BOUNDED BY A SINGLE MEMBRANE AND ARE SIMPLE SACS

RICH IN ACID PHOSPHATASE AND SEVERAL OTHER HYDROLYTIC

 ENZYMES. THESE ENZYMES ARE SYNTHESIZED ON RER AND ARE

 FURTHER PROCESSED IN THE GOLGI APPARATUS. 

AUTOPHAGOSOME; (AUTOPHAGY)

THE LYSOSOMES WHICH EAT PARTS OF THEIR OWN CELL ARE KNOWN AS 

AUTOPHAGOSOME.

★ DURING THIS PROCESS SOME OLD, WORN OUT PARTS OF CELL, SUCH AS

OLD MITOCHONDRIA ARE DIGESTED.

RELEASE OF ENZYMES;

LYSOSOMES ALSO RELEASE ENZYMES FOR EXTRA CELLULAR DIGESTION.

CAUSE OF DISEASES;

SEVERAL CONGENITAL DISEASES HAVE BEEN FOUND TO BE DUE TO 

ACCUMULATION WITHIN THE CELL OF SUBSTANCES SUCH AS GLYCOGEN 

OR VARIOUS GLYCOLIPIDS. 

★THEY ARE ALSO CALLED STORAGE DISEASES AND ARE PRODUCED BY 

MUTATION THAT AFFECT ONE OF THE LYSOSOMAL ENZYMES INVOLVED 

IN THE CATABOLISM OF A CERTAIN SUBSTANCE.

FOR EXAMPLE;

IN GLYCOGENESIS TYPE II DISEASE, 

          ➡THE LIVER AND MUSCLE APPEAR FILLED WITH GLYCOGEN WITHIN 

              MEMBRANE BOUND ORGANELLES. IN THIS DISEASE, AN ENZYME 

               THAT DEGRADES GLYCOGEN TO GLUCOSE, IS ABSENT.  

TAY-SACH'S DISEASE;

        ➡IT IS BECAUSE OF ABSENCE OF AN ENZYME THAT IS INVOLVED IN THE

           CATABOLISM OF LIPIDS. ACCUMULATION OF LIPIDS IN BRAIN CELLS 

            LEAD TO MENTAL RETARDATION AND EVEN DEATH.

 

lysosomes