Question

Which of the following enzymes is not present in succus entericus?
A.Lipase
B.Maltase
C.Nucleases
D.Nucleosidases

Answer 1

Hint: Succus entericus is also commonly called the intestinal juice. It has a pH of 7.6 and contains the secretion of enzymes and bicarbonates secretes inside the small intestine.

Complete step by step answer:
Digestion begins from the mouth by chewing the food particles. The salivary amylase enzyme present in the saliva breaks complex carbohydrates into comparatively simpler forms. The chewed food particle then runs down the esophagus from the buccal cavity. The epiglottis present allows the food to pass through the esophagus and prevent it from entering the wind-pipe. The food particles pass through the esophagus due to the downward peristalsis movement.
The food particles enter the stomach through a sphincter from the esophagus. In stomach parietal cells, goblet cells and chief cells produce HCl, pepsinogen, which gets activated in pepsin in the presence of acid, and mucus to protect the epithelial lining. Hormones like gastrin and are also produced in the stomach. The food is now called the chyme and passes to the small intestine, where the bile duct secretes enzyme cholecystokinin that helps in the emulsification of lipid particles in the chyme.
The pancreas secretes pancreatic amylase, lipases, peptidases, nucleosidases, and elastases to the small intestine and allows the digestion of lipids to fatty acids, complex carbohydrates to monosaccharides, proteins to amino acids and small peptides, and nucleotides into nucleoside units. The pancreatic enzymes are initially in the zymogen form but activation by enterokinase secrete the active form of enzymes along with bicarbonate.
Nucleases like exonuclease or endonuclease degrade the nucleic acid moiety and are not present in the intestinal juice.

Hence, the correct answer is an option (C).

Note:
Succus entericus is secreted mainly in the duodenal wall of the small intestine. It consists of water, bicarbonate, and enzymes to neutralize the chyme.