Question 1

Enzymes involved in the digestion of dietary protein in the small intestine include all of the following EXCEPT

Accepted Answer

A)  trypsin 
B)  elastase 
C)  chymotrypsin 
D)  carboxypeptidase A 
E)  pepsin 
A)  trypsin 
B)  elastase 
C)  chymotrypsin 
D)  carboxypeptidase A 
E)  pepsin

Question 2

Cellulose is not digested by humans because it

Accepted Answer

A)  is a relatively insoluble protein-carbohydrate complex inaccessible to digestive enzymes. 
B)  is a mucopolysaccharide, which is not a substrate for digestive enzymes. 
C)  is highly sulfated, making it inaccessible to the action of most glycosidases. 
D)  is a polymer of glucose molecules in beta 1-4 linkage for which we have no digestive enzymes. 
E)  resists enzyme action due to its highly branched structure. 
A)  is a relatively insoluble protein-carbohydrate complex inaccessible to digestive enzymes. 
B)  is a mucopolysaccharide, which is not a substrate for digestive enzymes. 
C)  is highly sulfated, making it inaccessible to the action of most glycosidases. 
D)  is a polymer of glucose molecules in beta 1-4 linkage for which we have no digestive enzymes. 
E)  resists enzyme action due to its highly branched structure.

Question 3

Chylomicrons are

Accepted Answer

A)  produced in the gut, and contain triglycerides, cholesterol, cholesteryl esters, protein, phospholipids. 
B)  produced in the liver and contain triglycerides, cholesterol, cholesteryl esters, protein, phospholipids. 
C)  produced in the intestine and the liver and contain largely cholesterol and phospholipids. 
D)  produced in the intestine and contain bile salts in addition to triglycerides, cholesterol and phospholipids. 
E)  the smallest of the serum lipoprotein particles. 
A)  produced in the gut, and contain triglycerides, cholesterol, cholesteryl esters, protein, phospholipids. 
B)  produced in the liver and contain triglycerides, cholesterol, cholesteryl esters, protein, phospholipids. 
C)  produced in the intestine and the liver and contain largely cholesterol and phospholipids. 
D)  produced in the intestine and contain bile salts in addition to triglycerides, cholesterol and phospholipids. 
E)  the smallest of the serum lipoprotein particles.

Question 4

All of the following statements about iron metabolism are correct EXCEPT

Accepted Answer

A)  iron is absorbed by the intestinal mucosa in the free Fe3+ form 
B)  overloading of iron in the body can occur as a result of repeated transfusions 
C)  transferrin is a glycoprotein that binds iron in the plasma 
D)  specific receptors for transferrin are probably required for delivery of iron to liver and erythropoietic tissue 
E)  ferritin stores iron in an oxidized form within a central cavity formed by its 24 subunits 
A)  iron is absorbed by the intestinal mucosa in the free Fe3+ form 
B)  overloading of iron in the body can occur as a result of repeated transfusions 
C)  transferrin is a glycoprotein that binds iron in the plasma 
D)  specific receptors for transferrin are probably required for delivery of iron to liver and erythropoietic tissue 
E)  ferritin stores iron in an oxidized form within a central cavity formed by its 24 subunits

Question 5

The complete digestion by humans of starch or glycogen to glucose requires

Accepted Answer

A)  only amylase. 
B)  only phosphorylase. 
C)  amylase, an oligo-alpha-1,6-glycosidase, and a maltase. 
D)  amylase and sucrase. 
E)  a poly-alpha-1,4-glucosidase. 
A)  only amylase. 
B)  only phosphorylase. 
C)  amylase, an oligo-alpha-1,6-glycosidase, and a maltase. 
D)  amylase and sucrase. 
E)  a poly-alpha-1,4-glucosidase.

Question 6

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 7

Human bile contains all of the following EXCEPT

Accepted Answer

A)  glycocholic acid. 
B)  mucin. 
C)  phosphoglycerides. 
D)  triacylglycerol. 
E)  taurocholic acid. 
A)  glycocholic acid. 
B)  mucin. 
C)  phosphoglycerides. 
D)  triacylglycerol. 
E)  taurocholic acid.

Question 8

The incorporation of iron is required in the biosynthesis of each of the following molecules EXCEPT

Accepted Answer

A)  hemoglobin 
B)  immunoglobulin G (IgG) 
C)  cytochrome c 
D)  myoglobin 
E)  catalase 
A)  hemoglobin 
B)  immunoglobulin G (IgG) 
C)  cytochrome c 
D)  myoglobin 
E)  catalase

Question 9

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 10

Dietary triacylglycerols are mainly hydrolyzed in the intestinal tract by

Accepted Answer

A)  hepatic lipase to glycerol and fatty acids. 
B)  hormone-sensitive lipase to glycerol and fatty acids. 
C)  hormone-sensitive lipase to monoacylglycerol and fatty acids. 
D)  pancreatic lipase to diacylglycerol and fatty acids. 
E)  pancreatic lipase to monoacylglycerol and fatty acids. 
A)  hepatic lipase to glycerol and fatty acids. 
B)  hormone-sensitive lipase to glycerol and fatty acids. 
C)  hormone-sensitive lipase to monoacylglycerol and fatty acids. 
D)  pancreatic lipase to diacylglycerol and fatty acids. 
E)  pancreatic lipase to monoacylglycerol and fatty acids.

Question 11

All of the following proteins bind iron EXCEPT

Accepted Answer

A)  ferritin. 
B)  ceruloplasmin. 
C)  haptoglobin. 
D)  transferrin. 
E)  calmodulin. 
A)  ferritin. 
B)  ceruloplasmin. 
C)  haptoglobin. 
D)  transferrin. 
E)  calmodulin.

Question 12

Most iron in the body is found as

Accepted Answer

A)  myoglobin. 
B)  hemoglobin. 
C)  complexed with transferrin. 
D)  uncomplexed in solution. 
E)  Fe(OH)3 precipitate (storage form). 
A)  myoglobin. 
B)  hemoglobin. 
C)  complexed with transferrin. 
D)  uncomplexed in solution. 
E)  Fe(OH)3 precipitate (storage form).

Question 13

The cell responds to an influx of toxic iron by:

Accepted Answer

A)  transcription of the ferritin gene to make new ferritin mRNA 
B)  splicing of stored ferritin pre-mRNA to produce new ferritin mRNA. 
C)  stabilizing the ferritin protein against proteolytic degradation. 
D)  derepressing the translation of ferritin mRNA. 
E)  converting an inactive form of ferritin to an active, iron-binding form. 
A)  transcription of the ferritin gene to make new ferritin mRNA 
B)  splicing of stored ferritin pre-mRNA to produce new ferritin mRNA. 
C)  stabilizing the ferritin protein against proteolytic degradation. 
D)  derepressing the translation of ferritin mRNA. 
E)  converting an inactive form of ferritin to an active, iron-binding form.

Question 14

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 15

Which molecule is synthesized in the stomach as a precursor of a proteolytic enzyme?

Accepted Answer

A)  pepsinogen 
B)  trypsinogen 
C)  chymotrypsin 
D)  enterokinase 
E)  progastrin 
A)  pepsinogen 
B)  trypsinogen 
C)  chymotrypsin 
D)  enterokinase 
E)  progastrin

Question 16

Which transport mechanism is unique to parietal cells for the transport of HCl?

Accepted Answer

A)  Cl-/HCO3- exchanger 
B)  Cl-/Na+ antiporter 
C)  Electrogenic Cl- flux 
D)  K+/H+ -exchanging ATPase 
E)  Na+/H+ transporter 
A)  Cl-/HCO3- exchanger 
B)  Cl-/Na+ antiporter 
C)  Electrogenic Cl- flux 
D)  K+/H+ -exchanging ATPase 
E)  Na+/H+ transporter

Question 17

The measurement of the iron binding capacity of serum is an indirect measurement of

Accepted Answer

A)  ceruloplasmin level 
B)  transferrin level 
C)  albumin level 
D)  total body stores of iron 
E)  hemoglobin concentration in red blood cells 
A)  ceruloplasmin level 
B)  transferrin level 
C)  albumin level 
D)  total body stores of iron 
E)  hemoglobin concentration in red blood cells

Question 18

The intestinal cell is probably unique in that it can

Accepted Answer

A)  Synthesize lipoprotein. 
B)  Acylate monoglyceride to form triglyceride. 
C)  Synthesize phosphatidic acid. 
D)  Absorb free fatty acids. 
E)  Utilize glucose to form glycerol phosphate. 
A)  Synthesize lipoprotein. 
B)  Acylate monoglyceride to form triglyceride. 
C)  Synthesize phosphatidic acid. 
D)  Absorb free fatty acids. 
E)  Utilize glucose to form glycerol phosphate.

Question 19

The action of pancreatic amylase followed by maltase on starch would yield

Accepted Answer

A)  fructose, isomaltose and glucose. 
B)  maltose, alpha-dextrins and lactose. 
C)  amylose and alpha-dextrins. 
D)  maltotriose, glucose and alpha-dextrins. 
E)  maltose, maltotriose and amylose. 
A)  fructose, isomaltose and glucose. 
B)  maltose, alpha-dextrins and lactose. 
C)  amylose and alpha-dextrins. 
D)  maltotriose, glucose and alpha-dextrins. 
E)  maltose, maltotriose and amylose.

Question 20

In order for cells to acquire iron all of the following are required except:

Accepted Answer

A)  transferrin receptors to be expressed on the surface of cells. 
B)  binding of transferrin to transferrin receptors. 
C)  alkalization of the endosome containing the transferrin_transferrin receptor complex. 
D)  endocytosis of the transferrin-transferrin receptor complex. 
A)  transferrin receptors to be expressed on the surface of cells. 
B)  binding of transferrin to transferrin receptors. 
C)  alkalization of the endosome containing the transferrin_transferrin receptor complex. 
D)  endocytosis of the transferrin-transferrin receptor complex.

Exam 26: Digestion and Absorption of Basic Nutritional Constituents

Enzymes involved in the digestion of dietary protein in the small intestine include all of the following EXCEPT

Cellulose is not digested by humans because it

Chylomicrons are

All of the following statements about iron metabolism are correct EXCEPT

The complete digestion by humans of starch or glycogen to glucose requires

Medium-chain triacylglycerols

Human bile contains all of the following EXCEPT

The incorporation of iron is required in the biosynthesis of each of the following molecules EXCEPT

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?

Dietary triacylglycerols are mainly hydrolyzed in the intestinal tract by

All of the following proteins bind iron EXCEPT

Most iron in the body is found as

The cell responds to an influx of toxic iron by:

Which of the following statements about bile acids is CORRECT?

Which molecule is synthesized in the stomach as a precursor of a proteolytic enzyme?

Which transport mechanism is unique to parietal cells for the transport of HCl?

The measurement of the iron binding capacity of serum is an indirect measurement of

The intestinal cell is probably unique in that it can

The action of pancreatic amylase followed by maltase on starch would yield

In order for cells to acquire iron all of the following are required except:

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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