Pretend you are a teacher preparing a quiz for the text I will provide. 
            Each quiz question should follow the format below. 
            Ensure that you carefully recheck the questions and answers for accuracy. 
            The output should be a ready-to-use list of dictionaries for the Python eval function:

            [

                    "question": "WRITE THE QUESTION HERE",
                    "options": ["A) OPTION_1", "B) OPTION_2", "C) OPTION_3", "D) OPTION_4"],
                    "answer": INDEX_OF_CORRECT_ANSWER_IN_OPTIONS_LIST,
                    "explanation": "EXPLAIN WHY THE ANSWER IS CORRECT"

            ]

            Text:
            de bonds.
❖Enzymes secreted by stomach:
▪Rennin:
➢It is also called chymosin.
➢It is active in infants and is absent in adults. It is important for coagulation of milk.
➢It acts on casein of milk to form paracasein which is immediately precipitated by Ca²⁺.
➢Its optimum pH is 4.0 and specificity of action is very similar to pepsin (hydrolyses peptide bonds connected
with L-aromatic amino acids).
Rennin
Renin
Site of synthesis
In the stomach
In the kidney
Class
Hydrolase (proteolytic enzyme)
Hydrolase (proteolytic enzyme)
Function
Coagulation of milk protein
activation of angiotensinogen to
angiotensin
Digestion of Dietary Proteins
▪Pepsin:
➢It is secreted as inactive zymogen form, pepsinogen.
✓Pepsinogen is activated (hydrolysed) in the stomach with the help of HCl then by pepsin itself 
(autocatalytically) to form the active pepsin.
➢It is synthesized in “chief cells” of stomach.
➢Pepsin  is an endopeptidase, hydrolyses the peptide bond formed by aromatic amino acids.
➢Its optimum pH = 2.
➢Pepsin hydrolyses proteins into proteoses and peptones.
▪Gelatinase:
➢Gelatinase is a proteolytic enzyme that allows a living organism to hydrolyse gelatin into its sub-
compounds that can cross the cell membrane and can be used by the organism. 
➢Gelatin is hydrolysed by this enzyme. It acts in an acidic medium
Digestion of Dietary Proteins
• Pepsin V Pepsinogen:
Digestion of proteins by pancreatic enzymes:
❖The optimum pH for pancreatic enzymes is pH= 8.
❖This pH is provided by the alkaline bile and pancreatic juice.
❖The secretion of pancreatic juice is stimulated by the peptide hormones, 
cholecystokinin and pancreozymin.
❖The pancreas secrets a group of proteases enzymes (trypsin, chymotrypsin, 
elastase and carboxypeptidase A, B).
▪Trypsin
➢In the small intestine, trypsinogen is activated by enterokinase (enteropeptidase).
➢Once activated, the trypsin activates other enzyme molecules.
➢Trypsin is endopeptidase enzyme catalysing hydrolysis of the peptide bonds formed by carboxyl groups of
basic amino acids Arg and Lys.
Digestion of proteins by pancreatic enzymes:
• Trypsinogen: 
➢Acute pancreatitis: Premature activation of trypsinogen inside the pancreas itself will result in the 
autodigestion of pancreatic cells. The result is acute pancreatitis. It is a life- threatening condition.
Digestion of proteins by pancreatic enzymes:
▪Chymotrypsin:
➢Is endopeptidase enzyme hydrolysing only when the carbonyl group of the peptide bond is
contributed by aromatic amino acids (Phe, Tyr, Trp) and (Met & Leu).
▪Elastase:
➢Is endopeptidase enzyme hydrolysing only when the carbonyl group of the peptide bond is 
contributed by small amino acids (Gly, Ala, Ser).
▪Carboxypeptidase A:
➢Is exopeptidase enzyme hydrolysing the peptide bond adjacent to free carboxyl group (C-
terminus) releasing single amino acid (Ala, Val, Leu or Ile).
▪Carboxypeptidase B:
➢Is exopeptidase enzyme hydrolysing the peptide bond adjacent to free carboxyl group (C-
terminus) releasing single amino

            Quiz: