UNIUYO BCH 200 Level Biochemistry Past Questions & Answers
UNIUYO BCH 200 Level Biochemistry Past Questions & Answers for First Semester Exams. Comprehensive guide covering carbohydrates, amino acids, proteins, and more for BCH 221 students.
UNIUYO BCH 200 Level Biochemistry Past Questions and Answers
1. Carbohydrates are polyhydroxy aldehydes or ketones and their derivatives or substances that yield such compound on hydrolysis.
Read also:UNIUYO FST 200 Level Compiled Exam Questions & First Semester
2. Importance of carbohydrates include:
The oxidation of carbohydrates is a central energy-building pathway in most non-photosynthetic cells.
They lubricate skeletal muscles thus bringing about recognition and adhesion between cells.
Carbohydrate polymers in proteins or lipids act as signals that determine intracellular location or metabolic fate (glycoconjugates).
Insoluble carbohydrate polymers serve as structural protective elements of bacterial and plant cell walls as well as connective tissues in animals.
3. Carbohydrates can be classified into Monosaccharides, Oligosaccharides, and Polysaccharides.
4. Saccharide is derived from the Greek word Sakcharon meaning “sugar.”
5. Monosaccharides can be sub-divided depending on the number of carbon atoms.
6. The most abundant carbohydrate in nature is Glucose, sometimes referred to as Dextrose.
7. Monosaccharides of more than four carbons tend to have cyclic structures — True.
8. Complete the table:
Trioses (C3H6O3): Glyceraldehyde – Dihydroxyacetone
Tetroses (C4H8O4): Erythrose – Erythrulose
Pentoses: Ribose, Xylose – Ribulose, Xylulose
Hexoses (C6H12O6): Glucose – Fructose, Psicose
Heptoses (C7H14O7): Glucoheptose – Sedoheptulose
9. D-Glucose has 5 hydroxyl groups.
10. Monosaccharides are soluble in water but insoluble in non-polar solvents.
11. In drawing a keto group, the first and last carbon will carry different functional groups — False.
12. Erythrose is found in synthesis of aromatic amino acid via the Shikinase pathway.
13. Aldopentoses & 2-deoxyribose are components of nucleotides and nucleic acids.
14. Oligosaccharides are short chains of monosaccharide units (2–10 molecules) linked by a glycosidic bond.
15. The most abundant oligosaccharides are Disaccharides.
16. D-Glucose + D-Glucose → Maltose.
17. Molecular composition of Raffinose: α-Galactose(1-6), α-Glucose(1-2), β-Fructose.
18. Molecular composition of Stachyose: α-Galactose(1-6), α-Galactose(1-6), α-Glucose(1-2), β-Fructose.
19. Examples of homopolysaccharides: Chitin, Inulin, Pectin, Starch, Cellulose, Glycogen.
20. Examples of heteropolysaccharides: Hyaluronic acid, Chondroitin, Pneumococcus type III polysaccharides.
21. Unit of chitin: N-acetylglucosamine.
22. Monosaccharide that does not exhibit optical activity: Dihydroxyacetone.
23. When hydroxyl group is on the right → D-isomer, on the left → L-isomer.
24. According to Le-Bell-Vant Hoff rule, number of optical isomers = 2ⁿ.
25. Preferred structures for monosaccharides in aqueous solution: Pyranose & Furanose.
26. Monosaccharides that differ only around the anomeric carbon are Anomers.
27. Mutarotation leads to formation of linear aldehyde or ketone — True.
28. α-D-Glucose rotation = 112.2°, β-D-Glucose rotation = 18.7°.
29. Two sugars differing around one carbon are Epimers.
30. Epimer at C2 of D-Glucose → Mannose, Epimer at C4 → Galactose.
31. During hemiacetal or hemiketal formation, water is released.
32. Monosaccharides oxidized by Ferric (Fe³⁺) and Cupric (Cu²⁺) ions.
33. Carbonyl carbon in D-Glucose oxidized gives D-Gluconic acid.
34. Qualitative test for reducing sugars: Fehling’s solution.
35. Enzyme catalyzing D-Glucose + O₂ → D-Gluconic-δ-lactone + H₂O: Glucose oxidase.
36. Oxidation at C1 and C6 yields D-Gluconic acid & D-Glucuronic acid.
37. Oxidation at both C1 and C6 yields Aldaric acid (e.g. D-Glucaric acid).
38. Aldoses and ketoses react with liquid ammonia to form Glucosylamine or at C2 Glucosamine.
39. Furfurals are produced by dehydrating monosaccharides with strong mineral acids.
40. Furfural condensation with phenols & amines yields coloured compounds.
41. α-D-Glucose dehydrates to form Hydroxymethyl furfural.
42. Osazones are formed by reaction of monosaccharides with excess phenylhydrazine.
43. Glucose, Mannose, and Fructose give same osazone — Glucosazone.
44. In sugar alcohol formation, carbonyl group undergoes reduction.
45. D-Glucose reacts with H₂ to form D-Glucitol & L-Sorbitol.
46. Sugar alcohol in lipids: Glycerol (propan-1,2,3-triol).
47. Importance of osazone:
To detect sugars in plants.
To differentiate reducing and non-reducing sugars.
To detect reducing sugars.
48. Human body contains 20% proteins.
49. Amino acids are the building blocks of proteins.
50. Amino acids linked by peptide bonds.
51. Amino acid definition: contains both amino group and carboxylic group.
52. Simplest amino acid: Glycine.
53. Side chains denoted by R.
54. Alanine’s side chain: CH₃.
55. Functional groups in amino acid: Carboxylic and Amino groups.
56. Alpha amino acids have carboxylic and amino groups attached to alpha carbon.
57. All amino acids exhibit chirality except Glycine.
58. Role of nonpolar amino acids: Maintain 3D protein structure.
59. Nonpolar amino acids subdivided into Alkyl (aliphatic) and Aromatic.
60. Derivative of Methionine: S-adenosyl methionine (SAM) – methyl donor in biochemical reactions.
61. Amino acids with polar OH group: Serine, Threonine, Tyrosine.
62. Two cysteines oxidize to form Cystine.
63. Histidine is a weak base because it is partially ionized at pH 7.
64. Essential vs nonessential amino acids:
Essential: needed in diet.
Nonessential: synthesized in body.
65. Zwitterion (Dipolar ion) forms when amino group protonated and carboxyl group deprotonated.
66. Acid-base properties of amino acids:
High melting point (~200°C)
Soluble in water
Amphoteric
Large dipole moments
67. Amino acids separated by electrophoresis viewed using Ninhydrin.
68. Product of Ninhydrin reaction: Ruhemann’s purple.
69. Side chain lost as an aldehyde.
70. Primary protein structure: sequence of amino acids in a chain.
71. Secondary structures: local folded structures due to atomic interactions.
72. Types of secondary structure: α-helix and β-pleated sheet.
73. Overall 3D structure: Tertiary structure.
74. Amino acids are protein building blocks — True.
75. Carbon atom in α-amino acid: Alpha carbon.
76. Alpha carbon bonds to COOH, NH₂, H, and R group.
77. Chirality centre: Asymmetric carbon atom.
78. Hydrophobic amino acids maintain 3D structure because they interact poorly with water.
79. Polar amino acids subdivided into Neutral, Acidic, and Basic.
80. Polar amino acids interact with water due to hydrogen bonding groups.
81. Polar hydroxyl groups not important — False.
82. Functions of hydroxyl groups:
Form phosphate ester of tyrosine.
Attach carbohydrates to serine/threonine.
83. Hydrogen bonding in asparagine/glutamine affects protein stability — True.
84. Sulfhydryl (-SH) of cysteine binds Iron and Copper.
85. Aspartic and Glutamic acids at physiological pH: Aspartate and Glutamate.
86. Basic amino acids form ionic bonds with acidic amino acids — True.
87. Table of amino acid derivatives:
GABA → Glutamate → Neurotransmitter
Serotonin, Melatonin → Tryptophan → Neurotransmitters
Thyroxine → Tyrosine → Hormone
Indole acetic acid → Tyrosine (plants) → Hormone
88. Histidine, Lysine, Arginine isoelectric points: 7.6, 9.7, 10.8.
89. Secondary structures held by hydrogen bonds.
90. Multiple subunits forming protein = Quaternary structure.
91. Example: Haemoglobin (4 subunits).
92. Class of acidic compounds with both carboxylic and aldehydic groups: Uronic acid.
93. Monosaccharides oxidized enzymatically at C6 yield Uronic acid (e.g. D-glucuronic acid).
94. D-Ribose reduces to form D-Ribitol.
95. Common sugar alcohols: Erythritol, Glycerol, Isomalt, Lactitol, Maltitol, Sorbitol.
96. Reagent distinguishing mono- and disaccharides: Barfoed’s reagent.
97. Reducing sugars include Maltose, Lactose, Glucose.
98. Oxidation of D-glucose at both ends yields Aldaric acids.
99. The main oxidizing agents of carbohydrates: Fehling’s and Benedict’s solutions.
100. α-D-Glucose + β-D-Glucose condensation forms Maltose.
101. Raffinose and Stachyose are examples of Oligosaccharides.
102. Hyaluronic acid is a Heteropolysaccharide.
103. Chitin is a Homopolysaccharide.
104. Hydrolysis of polysaccharides yields monosaccharides.
105. Monosaccharides exist in both open-chain and cyclic forms.
106. The glycosidic bond forms between anomeric carbon and hydroxyl group.
107. Reducing sugars have free aldehyde or ketone groups.
108. Amino acids act as buffers due to amphoteric nature.
109. Proteins may be simple or conjugated.
110. Structural organization of proteins includes primary, secondary, tertiary, and quaternary.
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