The functional unit of the Golgi apparatus is (a)Thylakoids (b)Oxysomes (c)Cristae (d)Cisternae
Hint: This helps in modifying, sorting, and packaging of proteins for secretion and also helps in the transportation of lipids and the formation of lysosomes.
Complete answer: The folds of the Golgi body are called cisternae which are called the functional units of this organelle. Golgi apparatus is a cell organelle found in the eukaryotic cells. It was discovered by Camillo Golgi in 1897 by an Italian physicist. Golgi apparatus forms a complex of vesicles and folded membranes within the cytoplasm that is involved in secretion and helps in intracellular transport. The appearance of the cisternae is generally compared to a stack of deflated balloons. Vesicles that extend from the endoplasmic reticulum enter the stacks of the Golgi body. It plays an important role in the modification and transport of proteins generated in the Endoplasmic Reticulum within the cell. The main function of this apparatus is to direct the carbohydrates and proteins, needed by the body, to their proper destination. The functions of cisternae change as it undergoes different stages of maturation. Immature cisternae receive vesicles from the endoplasmic reticulum. The next stage begins when cisternae swap material via vesicles at carbohydrate synthesis. When the cargo proteins are sent to transport carriers the mature cisternae reach the final stage.
So, the correct answer is 'Cisternae’.
Note: -A cisterna (plural cisternae) may be a flattened membrane disk of the endoplasmic reticulum and Golgi body. -A Golgi stack may contain anywhere from three to twenty cisternae, but most contain about six cisternae. -Golgi cisternae are often separated into four classes; cis, medial, trans, and TGN (trans-Golgi network). -Each sort of cisterna contains different enzymes to stop any redundant enzymatic activity. -Almost all cisternae within the Golgi body exhibit multiple stacking. However, there are evolutionary lineages during which the stacked characteristic has been lost.