Question 1

The digestion and absorption of starch involves hydrolysis to glucose

Accepted Answer

A)  followed by an antiport mechanism of absorption. 
B)  followed by phosphorylation and absorption of the glucose phosphate. 
C)  followed by absorption after conjugation with glutathione. 
D)  followed by absorption via a symport mechanism. 
E)  after endocytosis of starch by intestinal epithelial cells. 
A)  followed by an antiport mechanism of absorption. 
B)  followed by phosphorylation and absorption of the glucose phosphate. 
C)  followed by absorption after conjugation with glutathione. 
D)  followed by absorption via a symport mechanism. 
E)  after endocytosis of starch by intestinal epithelial cells.

Question 2

Medium-chain triacylglycerols

Accepted Answer

A)  are absorbed intact in the small intestine and are transported in the thoracic duct to blood as chylomicrons. 
B)  are not utilized in man because of a lack of pancreatic lipase specific for medium-chain triacylglycerols. 
C)  are readily absorbed in the small intestine and are transported in the portal vein. 
D)  contain mostly fatty acids having a chain length of 14-16 carbons. 
E)  none of the above. 
A)  are absorbed intact in the small intestine and are transported in the thoracic duct to blood as chylomicrons. 
B)  are not utilized in man because of a lack of pancreatic lipase specific for medium-chain triacylglycerols. 
C)  are readily absorbed in the small intestine and are transported in the portal vein. 
D)  contain mostly fatty acids having a chain length of 14-16 carbons. 
E)  none of the above.

Question 3

Which enzyme is responsible for the conversion of pepsinogen to pepsin?

Accepted Answer

A)  enteropeptidase 
B)  gastrin 
C)  pepsin 
D)  trypsin 
E)  Both B and C are correct. 
A)  enteropeptidase 
B)  gastrin 
C)  pepsin 
D)  trypsin 
E)  Both B and C are correct.

Question 4

Which enzyme of intestinal origin activates trypsinogen?

Accepted Answer

A)  pepsin 
B)  carboxypeptidase 
C)  chymotrypsin 
D)  enterokinase 
E)  cholecystokinin 
A)  pepsin 
B)  carboxypeptidase 
C)  chymotrypsin 
D)  enterokinase 
E)  cholecystokinin

Question 5

A typical property of a detergent is the formation of a micelle in solution. Under which of the following conditions is a detergent least likely to form micelles?

Accepted Answer

A)  at high detergent concentrations 
B)  in the presence of other amphipathic molecules 
C)  in the presence of low amounts of lysolecithin 
D)  at low detergent concentrations 
E)  None of the above; detergents always form micelles. 
A)  at high detergent concentrations 
B)  in the presence of other amphipathic molecules 
C)  in the presence of low amounts of lysolecithin 
D)  at low detergent concentrations 
E)  None of the above; detergents always form micelles.

Question 6

Sucrose is composed of

Accepted Answer

A)  two residues of D-glucose. 
B)  one residue each of D-glucose and D-fructose. 
C)  one residue each of D-glucose and D-galactose. 
D)  one residue each of D-galactose and D-fructose. 
E)  two residues of D-fructose. 
A)  two residues of D-glucose. 
B)  one residue each of D-glucose and D-fructose. 
C)  one residue each of D-glucose and D-galactose. 
D)  one residue each of D-galactose and D-fructose. 
E)  two residues of D-fructose.

Question 7

Which type of reaction BEST characterizes the process of digestion?

Accepted Answer

A)  hydrolysis 
B)  dehydration 
C)  dehydrogenation 
D)  phosphorolysis 
E)  hydrogenation 
A)  hydrolysis 
B)  dehydration 
C)  dehydrogenation 
D)  phosphorolysis 
E)  hydrogenation

Question 8

All of the following are true of mixed micelles formed in the intestine EXCEPT which one?

Accepted Answer

A)  They provide a vehicle for the absorption of fat soluble vitamins. 
B)  They are absorbed directly into the lymphatic system via the lacteals. 
C)  Cholesterol is often a component of micelles. 
D)  Micelles contain mainly free fatty acids and monoacylglycerols. 
E)  The non-polar ends of lipids are oriented toward the center of the micelles. 
A)  They provide a vehicle for the absorption of fat soluble vitamins. 
B)  They are absorbed directly into the lymphatic system via the lacteals. 
C)  Cholesterol is often a component of micelles. 
D)  Micelles contain mainly free fatty acids and monoacylglycerols. 
E)  The non-polar ends of lipids are oriented toward the center of the micelles.

Question 9

Which protein is synthesized in the intestine?

Accepted Answer

A)  trypsinogen 
B)  chymotrypsinogen 
C)  procarboxypeptidase 
D)  enterokinase 
E)  pepsin 
A)  trypsinogen 
B)  chymotrypsinogen 
C)  procarboxypeptidase 
D)  enterokinase 
E)  pepsin

Question 10

Concerning the bile acids, which of the following statements is/are CORRECT

Accepted Answer

A)  glycocholic and taurocholic acids are the major conjugated bile acids. 
B)  some of the conjugated bile acids are returned to the liver from the intestine via the enterohepatic circulation. 
C)  the major lipid components of bile, besides the conjugated bile acids, are phosphatidyl choline and cholesterol. 
D)  all of the above. 
E)  none of the above. 
A)  glycocholic and taurocholic acids are the major conjugated bile acids. 
B)  some of the conjugated bile acids are returned to the liver from the intestine via the enterohepatic circulation. 
C)  the major lipid components of bile, besides the conjugated bile acids, are phosphatidyl choline and cholesterol. 
D)  all of the above. 
E)  none of the above.

Question 11

All of the following statements about alpha-amylase are correct EXCEPT which one?

Accepted Answer

A)  Small branched dextrins are poor substrates for the enzyme. 
B)  Amylopectin and glycogen are normal substrates. 
C)  The major product of its action on amylose is glucose. 
D)  The enzyme catalyzes the hydrolysis of alpha-1,4-glucosidic linkages. 
E)  For humans, the most important occurrence of the enzyme is in the secretion of the pancreas. 
A)  Small branched dextrins are poor substrates for the enzyme. 
B)  Amylopectin and glycogen are normal substrates. 
C)  The major product of its action on amylose is glucose. 
D)  The enzyme catalyzes the hydrolysis of alpha-1,4-glucosidic linkages. 
E)  For humans, the most important occurrence of the enzyme is in the secretion of the pancreas.

Question 12

In the transport of glucose from the intestinal lumen through the epithelial cells, which of the following is NOT true?

Accepted Answer

A)  A metabolic poison (cyanide) or absence of oxygen would have no effect. 
B)  It requires sodium, potassium ATPase. 
C)  It is unidirectional. 
D)  It is stereospecific. 
E)  Cotransport with sodium occurs. 
A)  A metabolic poison (cyanide) or absence of oxygen would have no effect. 
B)  It requires sodium, potassium ATPase. 
C)  It is unidirectional. 
D)  It is stereospecific. 
E)  Cotransport with sodium occurs.

Question 13

Which of the following statements about bile acids is CORRECT?

Accepted Answer

A)  bile acids are required for the absorption of vitamins A and K 
B)  Taurodeoxycholic acid is a primary conjugated bile acid. 
C)  Glycochenodeoxycholic acid is a secondary conjugated bile acid. 
D)  The presence of high concentrations of bile acids stimulates the synthesis of additional bile acids. 
E)  The rate-limiting step in their synthesis is decarboxylation. 
A)  bile acids are required for the absorption of vitamins A and K 
B)  Taurodeoxycholic acid is a primary conjugated bile acid. 
C)  Glycochenodeoxycholic acid is a secondary conjugated bile acid. 
D)  The presence of high concentrations of bile acids stimulates the synthesis of additional bile acids. 
E)  The rate-limiting step in their synthesis is decarboxylation.

Question 14

Lactose intolerance is caused by deficient activity of

Accepted Answer

A)  galactose 1-phosphate uridylyltransferase. 
B)  amylase. 
C)  lactose dehydrogenase. 
D)  lactase. 
E)  galactokinase. 
A)  galactose 1-phosphate uridylyltransferase. 
B)  amylase. 
C)  lactose dehydrogenase. 
D)  lactase. 
E)  galactokinase.

Question 15

What is the principal physiological function of bile salts?

Accepted Answer

A)  To permit cholesterol catabolism. 
B)  To catalyze lipid digestion. 
C)  To permit gastrointestinal absorption of dietary lipid. 
D)  To control enterohepatic circulation. 
E)  To regulate blood cholesterol levels. 
A)  To permit cholesterol catabolism. 
B)  To catalyze lipid digestion. 
C)  To permit gastrointestinal absorption of dietary lipid. 
D)  To control enterohepatic circulation. 
E)  To regulate blood cholesterol levels.

Question 16

The formation of chylomicrons takes place in the

Accepted Answer

A)  adipose tissue where stored triacylglycerols are mobilized. 
B)  small intestine where dietary triacylglycerols are digested and absorbed. 
C)  liver where cholesterol and apolipoproteins are synthesized. 
D)  blood where circulating lipoproteins are degraded by lipases. 
A)  adipose tissue where stored triacylglycerols are mobilized. 
B)  small intestine where dietary triacylglycerols are digested and absorbed. 
C)  liver where cholesterol and apolipoproteins are synthesized. 
D)  blood where circulating lipoproteins are degraded by lipases.

Question 17

All of the following are part of the process of protein digestion EXCEPT

Accepted Answer

A)  denaturation of many proteins at the pH of gastric juice. 
B)  the action of enteropeptidase (enterokinase) on pro-aminopeptidase. 
C)  conversion of pepsinogen to pepsin by the action of pepsinogen. 
D)  catalysis of protein hydrolysis by both endo- and exopeptidases. 
E)  the action of specific dipeptidases. 
A)  denaturation of many proteins at the pH of gastric juice. 
B)  the action of enteropeptidase (enterokinase) on pro-aminopeptidase. 
C)  conversion of pepsinogen to pepsin by the action of pepsinogen. 
D)  catalysis of protein hydrolysis by both endo- and exopeptidases. 
E)  the action of specific dipeptidases.

Question 18

The major site of carbohydrate digestion is the

Accepted Answer

A)  mouth. 
B)  stomach. 
C)  small intestine. 
D)  large intestine. 
E)  pancreas. 
A)  mouth. 
B)  stomach. 
C)  small intestine. 
D)  large intestine. 
E)  pancreas.

Question 19

Glucose absorption:

Accepted Answer

A)  occurs without the need for a transport protein in muscle cells. 
B)  needs an active Na+ pump in liver cells. 
C)  requires insulin in the brain. 
D)  is stimulated by glucagon in the liver. 
E)  occurs against a concentration gradient in the intestinal mucosa. 
A)  occurs without the need for a transport protein in muscle cells. 
B)  needs an active Na+ pump in liver cells. 
C)  requires insulin in the brain. 
D)  is stimulated by glucagon in the liver. 
E)  occurs against a concentration gradient in the intestinal mucosa.

Question 20

Which of the following is involved in the conversion of a zymogen into an active enzyme in the intestine?

Accepted Answer

A)  carboxypeptidase 
B)  cholecystokinin 
C)  pepsin 
D)  enterokinase 
E)  all of the above 
A)  carboxypeptidase 
B)  cholecystokinin 
C)  pepsin 
D)  enterokinase 
E)  all of the above

Exam 25: Digestion and Absorption of Basic Nutritional Constituents

The digestion and absorption of starch involves hydrolysis to glucose

Medium-chain triacylglycerols

Which enzyme is responsible for the conversion of pepsinogen to pepsin?

Which enzyme of intestinal origin activates trypsinogen?

A typical property of a detergent is the formation of a micelle in solution. Under which of the following conditions is a detergent least likely to form micelles?

Sucrose is composed of

Which type of reaction BEST characterizes the process of digestion?

All of the following are true of mixed micelles formed in the intestine EXCEPT which one?

Which protein is synthesized in the intestine?

Concerning the bile acids, which of the following statements is/are CORRECT

All of the following statements about alpha-amylase are correct EXCEPT which one?

In the transport of glucose from the intestinal lumen through the epithelial cells, which of the following is NOT true?

Which of the following statements about bile acids is CORRECT?

Lactose intolerance is caused by deficient activity of

What is the principal physiological function of bile salts?

The formation of chylomicrons takes place in the

All of the following are part of the process of protein digestion EXCEPT

The major site of carbohydrate digestion is the

Glucose absorption:

Which of the following is involved in the conversion of a zymogen into an active enzyme in the intestine?

Eukaryotic Cell Structure

DNA and RNA: Composition and Structure

Protein I: Composition and Structure

DNA Replication, Recombination, and Repair

RNA: Transcription and Rna Processing

Protein Synthesis: Translation and Posttranslational Modifications

Recombinant Dna and Biotechnology

Regulation of Gene Expression

Protein II: Structure-Function Relationships in Protein Families

Enzymes: Classification, Kinetics, and Control

The Cytochromes P450 and Nitric Oxide Synthases

Biological Membranes: Structure and Membrane Transport

Fundamentals of Signal Transduction

Bioenergetics and Oxidative Metabolism

Carbohydrate Metabolism I: Major Metabolic Pathways and Their Control

Carbohydrate Metabolism II: Special Pathways and Glycoconjugates

Lipid Metabolism I: Synthesis, Storage, and Utilization of Fatty Acids and Triacylglycerols

Lipid Metabolism II: Pathways of Metabolism of Special Lipids

Amino Acid Metabolism

Purine and Pyrimidine Nucleotide Metabolism

Metabolic Interrelationships

Biochemistry of Hormones

Molecular Cell Biology

Cell Cycle, Programmed Cell Death, and Cancer

Digestion and Absorption of Basic Nutritional Constituents

Principles of Nutrition I and II

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