Most prokaryotes carry a small amount of genetic material in the form of a single molecule, or chromosome, of circular DNA. The DNA in prokaryotes is contained in a central area of the cell called the nucleoid, which is not surrounded by a nuclear membrane.

The nuclear envelope keeps the contents of the nucleus, called the nucleoplasm, separate from the cytoplasm of the cell. The all-important genetic material, mainly the DNA is kept separate and relatively safe from the chemical reactions taking place in the cytoplasm.

Without the nuclear membrane the cell would collapse and die. Without the cell membrane, any chemical would be allowed to enter. Membranes are very important because they help protect the cell. Materials move across the membrane by diffusion.

The nuclear envelope is perforated with tiny holes known as nuclear pores, which were first discovered in the mid-twentieth century. These pores regulate the passage of molecules between the nucleus and cytoplasm, permitting some to pass through the membrane, but not others.

If there were no lysosomes in the cell, it will not be able to digest food and there would be accumulation of wastes like worn out parts inside the cell. Thus, cell will not be able to survive. Lysosome (also called suicide sacs) have proteins that break down waste.

• The Red blood cells do not contain lysosomes, mitochondria, nucleus etc.
• The absence of cellular organelles help them to accommodate maximum space for haemoglobin and helps in carrying more oxygen.
• It also gives a distinctive bi-concave shape to these cells and also helps in diffusion.

Lysosomes are found in all animal cells, but are most numerous in disease-fighting cells, such as white blood cells. This is because white blood cells must digest more material than most other types of cells in their quest to battle bacteria, viruses, and other foreign intruders.

Lysosomes are membrane-bound vesicles that contain digestive enzymes, such as glycosidases, proteases and sulfatases. Lysosomal enzymes are synthesized in the endoplasmic reticulum (ER), are transported to the Golgi apparatus, and are tagged for lysosomes by the addition of mannose-6-phosphate label.

Lysosomes are involved with various cell processes. They break down excess or worn-out cell parts. They may be used to destroy invading viruses and bacteria. If the cell is damaged beyond repair, lysosomes can help it to self-destruct in a process called programmed cell death, or apoptosis.

Lysosomes are formed from the fusion of vesicles from the Golgi complex with endosomes. Endosomes are vesicles that are formed by endocytosis as a section of the plasma membrane pinches off and is internalized by the cell. In this process, extracellular material is taken up by the cell.

Although the signs and symptoms vary from disease to disease in this group, symptoms occur in each case because of an enzyme deficiency that inhibits the ability of the lysosomes present in each of the body’s cells to perform their normal function. The lysosomes function as the primary digestive units within cells.

The defective degradation of glycogen in the lysosomes is caused by the lack of a single enzyme, lysosomal acid alpha-glucosidase resulting in glycogen storage disease type II (Pompe disease).

Types of Lysosomal Storage Diseases?

• Gaucher disease.
• Niemann-Pick disease.
• Fabry disease.
• Tay-Sachs disease.
• Mucopolysaccharidoses (MPS) diseases.
• Pompe disease.

Lysosomal storage disorders

• AB variant.
• Activator deficiency.
• Sandhoff disease. Infantile. Juvenile. Adult onset.
• Tay–Sachs. Juvenile hexosaminidase A deficiency. Chronic hexosaminidase A deficiency.

Gaucher disease is a rare, inherited metabolic disorder in which deficiency of the enzyme glucocerebrosidase results in the accumulation of harmful quantities of certain fats (lipids), specifically the glycolipid glucocerebroside, throughout the body especially within the bone marrow, spleen and liver.

Fabry disease is an inherited disorder that results from the buildup of a particular type of fat, called globotriaosylceramide, in the body’s cells. Beginning in childhood, this buildup causes signs and symptoms that affect many parts of the body.

Some of the most common lysosomal storage disorders include:

• Gaucher disease: Gaucher disease often causes spleen and liver enlargement, blood problems and bone issues.
• Fabry disease: This disorder often causes severe burning pains in hands and feet and, in some cases, a distinctive skin rash on the legs.