1. Which enzyme specifically adds N-acetylgalactosamine to the O antigen in the ABO blood group system?

A. Type B transferase B. Maltase C. Type A transferase D. Sucrase

2. How do glycosyltransferases differ from the enzymes responsible for polypeptide and oligonucleotide assembly?

A. They use a template for synthesis B. A single enzyme catalyzes all bond formations C. They catalyze glycosidic bond formation without a single central enzyme or template D. They assemble linear chains only

3. Which enzyme hydrolyzes lactose in humans?

A. β-galactosidase B. Lactase C. Maltase D. Sucrase

4. Which blood group antigen differs from the O antigen by the addition of N-acetylgalactosamine?

A. A antigen B. B antigen C. AB antigen D. None of the above

5. How are amylopectin and glycogen structurally similar?

A. Both are unbranched polymers B. Both have α-1,4 linkages with α-1,6 branch points C. Both have β-1,4 glycosidic bonds only D. Both contain N-acetylglucosamine units

6. What sugar units does lactose yield upon hydrolysis?

A. Glucose and fructose B. Glucose and galactose C. Two glucose molecules D. Two galactose molecules

7. Which polysaccharide serves primarily a structural role in plants?

A. Amylose B. Amylopectin C. Glycogen D. Cellulose

8. How do glycosyltransferases contribute to the ABO blood group antigens?

A. By degrading blood group antigens B. By adding specific monosaccharides to the O antigen C. By changing the protein backbone of red blood cells D. By removing carbohydrates from the cell surface

9. Which of the following monosaccharide residues is linked through an α-1,3 glycosidic bond in the A and B blood group antigens?

A. Glucose B. N-acetylgalactosamine or galactose C. Fructose D. Lactose

10. How often do α-1,6 glycosidic bonds appear in glycogen to create branch points?

A. Every 5 glucose units B. Every 10 glucose units C. Every 20 glucose units D. Every 30 glucose units

11. What occurs during glycosyltransferase-catalyzed reactions regarding stereochemistry?

A. Reactions always invert configuration at the anomeric carbon B. Reactions can proceed with either retention or inversion of configuration at the glycosidic carbon C. Configuration is lost during the reaction D. Configuration changes randomly

12. What is the major storage form of glucose in animals?

A. Amylose B. Glycogen C. Cellulose D. Amylopectin

13. Why can mutations in glycosyltransferase genes lead to blood type O phenotype?

A. They enhance enzyme activity B. They cause premature termination of translation resulting in no active enzyme C. They add extra monosaccharides to antigens D. They change antigen backbone

14. What is unique about the glycosyltransferase enzyme in individuals with the O blood type?

A. It adds an extra glucose B. It transfers N-acetylgalactosamine C. It is nonfunctional due to a mutation D. It only adds fructose

15. What distinguishes cellulose from starch in terms of glycosidic linkages?

A. Cellulose has α-1,4 linkages, starch has β-1,4 B. Cellulose has β-1,4 linkages, starch has α-1,4 C. Cellulose has α-1,6 linkages, starch has β-1,6 D. Both have the same linkages

16. What characteristic allows cellulose to form very long straight chains?

A. α-1,4 glycosidic linkages B. β-1,4 glycosidic linkages C. α-1,6 glycosidic linkages D. β-1,6 glycosidic linkages

17. What is the main function of glycosyltransferases in carbohydrate assembly?

A. Hydrolyze glycosidic bonds B. Catalyze formation of glycosidic bonds C. Oxidize sugars D. Transport sugars across membranes

18. What causes postmortem glycogenolysis to stop at pH 5.5?

A. Activation of enzymes B. Formation of lactic acid lowering pH C. Increase in oxygen concentration D. Depletion of substrates

19. What is the hydrolysis product of sucrose?

A. Two glucose molecules B. Glucose and fructose C. Glucose and galactose D. Two fructose molecules

20. What is the main reason for the presence of different blood types in the human population?

A. Random genetic mutations only B. Dietary influences on blood composition C. Selective pressure to prevent parasitic mimicry of blood-group antigens D. Climate variations affecting blood chemistry

21. What is the primary physiological role of glycogen in animals?

A. Structural support B. Energy storage C. Transport of oxygen D. Cell signaling

22. What is the difference in the enzymatic action between α-amylase and β-amylase during starch degradation?

A. α-Amylase acts at the non-reducing end, β-amylase acts randomly B. α-Amylase randomly cleaves internal α-1,4 bonds, β-amylase cleaves from the non-reducing end C. Both enzymes perform random cleavage D. Both enzymes cleave from the reducing end

23. What is the difference between amylose and amylopectin in starch?

A. Amylose is branched; amylopectin is unbranched B. Amylose contains β-linkages; amylopectin contains α-linkages C. Amylose is unbranched; amylopectin is branched with α-1,6 linkages D. Both have the same structure but differ in solubility

24. Which enzyme is present in human saliva and pancreatic juice to hydrolyze starch?

A. β-amylase B. α-amylase C. Sucrase D. Lactase

25. Which disaccharide is formed by glucose and fructose linked through α-1,β-2 glycosidic bond?

A. Lactose B. Maltose C. Sucrose D. Cellobiose

26. Which enzyme in bacteria hydrolyzes lactose?

A. Maltase B. Sucrase C. β-galactosidase D. α-amylase

27. What is the main characteristic of lactose that differentiates it from sucrose?

A. It is non-reducing B. It contains galactose C. It is composed of glucose and fructose D. It lacks mutarotation

28. How does parasitic mimicry contribute to blood group diversity?

A. Parasites only infect people with rare blood types B. Mimicry causes universal susceptibility to infection C. Parasites expressing antigens similar to a specific blood group avoid detection, leading to selective pressure for antigen variation D. Parasites destroy all blood antigens indiscriminately

29. What monosaccharide is attached to the O antigen to form the B antigen?

A. Glucose B. N-acetylgalactosamine C. Galactose D. Mannose

30. What type of bond links the two monosaccharides in a disaccharide?

A. Peptide bond B. O-glycosidic bond C. Phosphodiester bond D. Hydrogen bond

31. Which enzyme catalyzes the hydrolysis of maltose in the human intestine?

A. Sucrase B. Maltase C. Lactase D. β-galactosidase

32. Why is sucrose considered a non-reducing sugar?

A. It contains glucose only B. It has both anomeric carbons involved in the glycosidic linkage C. It undergoes mutarotation rapidly D. It has free aldehyde groups

33. What role do sugar nucleotides play in glycosyltransferase reactions?

A. They are structural components of polysaccharides B. They act as activated sugar donors for glycosidic bond formation C. They inhibit glycosyltransferase activity D. They serve as templates for sugar assembly

34. Why is maltose considered a reducing sugar?

A. Because both glucose units are linked at their anomeric carbons B. Because one glucose has a free anomeric carbon C. Because it contains fructose D. Because it is non-hydrolyzable

35. Which disaccharide consists of two glucose units linked by α-1,4 glycosidic bonds?

A. Maltose B. Lactose C. Sucrose D. Cellobiose

36. What evolutionary advantage does blood type diversity confer?

A. It enhances nutritional absorption B. It prevents any single parasite from surviving in all individuals C. It increases red blood cell count D. It promotes faster wound healing

37. Which enzyme hydrolyzes lactose in the human small intestine?

A. Maltase B. Lactase C. Sucrase D. Amylase

38. Which enzyme found in saliva and pancreatic juice hydrolyzes starch?

A. β-amylase B. Sucrase C. α-Amylase D. Lactase

39. What characterizes the O blood group phenotype at the molecular level?

A. Addition of galactose to the O antigen B. Presence of both type A and B glycosyltransferases C. No active glycosyltransferase due to premature termination mutation D. Extra N-acetylgalactosamine attached to glycans

40. What sugar residues does α-amylase act upon, and where?

A. β-1,4 linkages, at non-reducing ends B. α-1,4 linkages, randomly within starch molecule C. α-1,6 linkages only D. β-1,6 linkages at branch points

41. Which enzyme class is responsible for catalyzing the formation of glycosidic bonds during oligosaccharide assembly?

A. Hydrolases B. Glycosyltransferases C. Kinases D. Ligases

42. Why does sucrose not exhibit reducing properties?

A. Because it lacks glucose B. Because both anomeric carbons are involved in the glycosidic bond C. Because it is composed of two fructose units D. Because it is insoluble in water

43. What is the primary function of glycogen in animals?

A. Structural support in cell walls B. Energy storage in liver and muscle C. Transport of oxygen D. Signal transduction

44. Which glycosidic linkage is present in lactose?

A. α-1,4 B. β-1,4 C. α-1,6 D. β-1,6

45. How frequently do branch points occur in glycogen molecules?

A. Every 2 glucose units B. Every 5 glucose units C. Approximately every 10 glucose units D. No branch points exist

46. Why do different blood types exist in human populations?

A. To improve oxygen transport efficiency B. As a result of parasitic mimicry leading to selective pressure for antigen diversity C. Because of geographic isolation D. Due to dietary differences

47. What type of carbohydrate polymer is starch classified as?

A. Heteropolysaccharide B. Homopolysaccharide C. Glycoprotein D. Glycolipid

48. In the assembly of oligosaccharides, what is the form of the sugar donor substrate?

A. Free monosaccharide B. Sugar nucleotide C. Sugar phosphate D. Sugar phosphate ester

49. What sugar does the type A glycosyltransferase add to the O antigen in the ABO blood group system?

A. Galactose B. N-acetylgalactosamine C. Glucose D. Fructose

50. What happens during glycosyltransferase-catalyzed synthesis in terms of stereochemistry?

A. Configuration at the glycosidic carbon is always inverted B. Configuration at the glycosidic carbon can be either retained or inverted depending on the enzyme C. Stereochemistry is not affected during the reaction D. It involves formation of peptide bonds