Question

Gastric cells secreting zymogens have well developed
A. SER
B. RER
C. Mitochondria
D. Plastids

Answer 1

Zymogen cells or chief cells in the stomach are cells that release pepsinogen and gastric lipase. These cells release chymosin in the stomach of ruminants. These cells are located deep in the mucosal layer lining the stomach.

Complete answer:
-ER
Endoplasmic reticulum is a well-developed electron microscopic network of interconnected cisternae, tubules and vesicles present throughout the cytoplasm, especially in the endoplasm. It is of two types:
-RER
Rough endoplasmic reticulum- It is formed from SER by the loss of ribosomes. It is involved in the protein synthesis and also forms the transition vesicles that carry materials to the cisternae of Golgi apparatus.
-SER
Smooth endoplasmic reticulum-It helps in glycogenolysis in the liver cell. It also helps in the detoxification of the harmful drugs like phenobarbital, carcinogens etc.
-Mitochondria
It is also called the energy producing cell organelle in the cell. It is a rod-shaped organelle with a diameter of about 0.5-1 micron meter and a variable length that may range up to 7 micron meter.
It contains several ribosomes, soluble proteins, enzymes of Krebs’ cycle and nucleic acids. Within the cell the site of respiration or oxidative phosphorylation is mitochondria. The end product of the glycolysis is pyruvic acid which enters mitochondria and takes part in Krebs’ cycle in the mitochondrial matrix.
-Plastids
It is double walled, DNA containing the largest organelle in plant cells. It was discovered by Haeckel in 1865.
On the basis of their specific functions and pigments present in them, they are classified into two types- leucoplasts and chromoplasts.
The correct answer is B. RER.

Note: The zymogenic cells secretes enzymes like pepsin and rennin that help in protein digestion. Pepsin is an endopeptidase which breaks peptide bonds into peptones, proteases and polypeptides.