Question

Secondary lysosomes are-
A. Digestive vacuoles
B. Autophagic vacuoles
C. Residual vacuoles
D. All of the above

Answer 1

Hint: Lysosomes are found in animal cells and some plants cell, and the key function of the lysosome is breaking down different types of biological material including nucleic acids, lipids, and proteins among others with the help of enzymes contained in it.

Complete answer:
A lysosome is a cell organelle found in both the animal cells and some plant cells. This organelle is known as the digestive unit of a cell. Lysosomes are single membrane-bounded small vesicles that contain hydrolytic enzymes which are capable of hydrolysing any kind of biomolecules. They are indulged in various cell processes such as plasma membrane repair, apoptosis, cell signalling, removal of waste products and energy metabolism.
There are two main types of lysosomes that are found which are primary and secondary lysosomes. Primary lysosomes are developed from Golgi bodies. The primary lysosomes are surrounded by a single phospholipid layer and contain acid hydrolases.
When the primary lysosome fuses with a phagosome, it gives rise to secondary lysosomes. This fusion is also occurring due to the previously inactivation of enzymes in order to become active. Secondary lysosomes are larger in size than the primary lysosomes. This lysosome has the ability to release enzymes outside the cell to degrade the foreign particle i.e. nucleic material.
Secondary lysosomes are also called heterophagosome or digestive vacuoles as it helps in digestion of food particles. Food particles are degraded into the vacuole by the help of lytic enzymes present in the secondary lysosome. In secondary lysosomes digest materials absorbed from outside of the cell by the process phagocytosis and it becomes phagosomes. They may absorb outworn organelles and that is the reason that secondary lysosomes are also known as autophagic vacuoles.
In the lysosomal digestion process, the residual bodies are a type of vesicles that contain indigestible materials. Residual bodies are secreted by the cell via the exocytosis process.

Therefore, the correct and appropriate option is option D.

Note:
Secondary lysosomes are a type of lysosomes, which generates from the fusion of primary lysosomes with the phagosome. Secondary lysosomes mainly operate the digestion of nucleic material or foreign particles. As secondary lysosomes absorb the outworn material from the outside of the cells so it is called autophagic. During lysosomal digestion, residual bodies are also secreted.