Podcast
Questions and Answers
Amino acids are primarily involved in the synthesis of carbohydrates and fats.
Amino acids are primarily involved in the synthesis of carbohydrates and fats.
False (B)
What is the average protein turnover rate in a 70 kg man?
What is the average protein turnover rate in a 70 kg man?
400 g per day
Which of the following amino acids are obtained from the diet?
Which of the following amino acids are obtained from the diet?
Protein synthesis can occur even if the body is deficient in essential amino acids.
Protein synthesis can occur even if the body is deficient in essential amino acids.
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How is nitrogen balance maintained in the body?
How is nitrogen balance maintained in the body?
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What type of molecules are dietary proteins?
What type of molecules are dietary proteins?
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Dietary proteins are easily absorbed directly from the intestine.
Dietary proteins are easily absorbed directly from the intestine.
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What happens to dietary proteins during cooking?
What happens to dietary proteins during cooking?
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What class of enzymes are proteolytic enzymes?
What class of enzymes are proteolytic enzymes?
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Proteolytic enzymes are secreted in their active form.
Proteolytic enzymes are secreted in their active form.
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Which of the following is NOT an example of an endopeptidase?
Which of the following is NOT an example of an endopeptidase?
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Exopeptidases work by breaking peptide bonds at the ends of the polypeptide chain.
Exopeptidases work by breaking peptide bonds at the ends of the polypeptide chain.
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What is the name of the enzyme that acts on the peptide bond at the carboxyl terminal end of the polypeptide chain?
What is the name of the enzyme that acts on the peptide bond at the carboxyl terminal end of the polypeptide chain?
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Which cells in the stomach secrete hydrochloric acid?
Which cells in the stomach secrete hydrochloric acid?
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Hydrochloric acid denatures proteins by lowering the pH.
Hydrochloric acid denatures proteins by lowering the pH.
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What is the inactive form of pepsin called?
What is the inactive form of pepsin called?
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The conversion of pepsinogen to pepsin is triggered by the removal of ______ amino acids from the N-terminal end.
The conversion of pepsinogen to pepsin is triggered by the removal of ______ amino acids from the N-terminal end.
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What is the optimal pH for pepsin activity?
What is the optimal pH for pepsin activity?
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Pepsin is a type of exopeptidase.
Pepsin is a type of exopeptidase.
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Which amino acids are involved in peptide bond hydrolysis by Pepsin?
Which amino acids are involved in peptide bond hydrolysis by Pepsin?
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What are the two end products of protein breakdown by Pepsin?
What are the two end products of protein breakdown by Pepsin?
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Rennin is active in both infants and adults.
Rennin is active in both infants and adults.
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What is the name of the milk protein that is converted to paracasein by rennin?
What is the name of the milk protein that is converted to paracasein by rennin?
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Pancreatic enzymes work optimally in an acidic environment.
Pancreatic enzymes work optimally in an acidic environment.
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What hormone stimulates the secretion of pancreatic juice?
What hormone stimulates the secretion of pancreatic juice?
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Which of the following is NOT an endopeptidase secreted by the pancreas?
Which of the following is NOT an endopeptidase secreted by the pancreas?
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Pancreatic enzymes are secreted in their active form.
Pancreatic enzymes are secreted in their active form.
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What activates trypsinogen to trypsin?
What activates trypsinogen to trypsin?
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Trypsin can activate other pancreatic enzymes.
Trypsin can activate other pancreatic enzymes.
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What is the function of chymotrypsin in protein digestion?
What is the function of chymotrypsin in protein digestion?
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Chymotrypsin is secreted in its active form.
Chymotrypsin is secreted in its active form.
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What is the optimal pH for the activity of chymotrypsin?
What is the optimal pH for the activity of chymotrypsin?
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What happens if trypsinogen is activated prematurely inside the pancreas?
What happens if trypsinogen is activated prematurely inside the pancreas?
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Elastase is a type of exopeptidase.
Elastase is a type of exopeptidase.
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What is the inactive form of elastase called?
What is the inactive form of elastase called?
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Elastase primarily digests ______ and ______.
Elastase primarily digests ______ and ______.
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Study Notes
Amino Acid Metabolism
- Amino acids are crucial for building structural and functional proteins.
- Humans don't store proteins, so synthesis and breakdown rates are balanced.
- Essential amino acids must come from diet.
- Non-essential amino acids can be made by the body or ingested.
Digestion and Absorption of Proteins
- Dietary proteins are too large to be absorbed directly.
- Digestion breaks them into smaller amino acids.
- Hydrolases (class 3 enzymes) break down proteins in the digestive process.
- Proteolytic enzymes are secreted in inactive forms (zymogens) and activated in the intestine.
Endopeptidases
- These enzymes break peptide bonds within protein molecules.
- Examples include pepsin, trypsin, chymotrypsin, and elastase.
Exopeptidases
- They break peptide bonds at the ends of polypeptide chains.
- Carboxypeptidase cleaves peptide bonds at the carboxyl end.
- Aminopeptidase cleaves peptide bonds at the amino end.
Gastric Digestion
- Hydrochloric acid is secreted to create optimal pH for pepsin.
- Hydrochloric acid also denatures proteins.
- Pepsin, an endopeptidase, breaks down proteins into proteoses and peptones.
Rennin (Chymosin)
- Important in infants for curdling milk.
- Rennin converts casein to paracasein.
- This denatured protein is digestible by pepsin.
Pancreatic Digestion
- Pancreatic enzymes function best at a pH of 8 (alkaline).
- Pancreatic juice contains endopeptidases like trypsin, chymotrypsin, and elastase.
- These work alongside carboxypeptidase.
- Trypsinogen is activated to trypsin by enterokinase.
Trypsin
- Trypsin activates other digestive enzymes.
- It hydrolyzes peptide bonds involving basic amino acids.
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Description
This quiz explores key concepts related to amino acid metabolism and the digestion and absorption of proteins. It covers essential and non-essential amino acids, as well as the roles of various enzymes in protein breakdown. Test your understanding of how proteins are processed in the human body and the importance of amino acids in nutrition.
