Biochemistry Past Questions for 200 Level Students | Exam Prep

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Biochemistry Past Questions for 200 Level Students | Exam200-level Prep

NOTE: Some of the answers might not be 100% accurate. It is advisable you research on some of the answers and questions. This is UNIUYO biochemistry past questions. Prepare well and study it in line with your current  syllabus and handbook. Smash your A and thank us later. We have complete questions contact for more..

1. Carbohydrates are ______ polyhydroxy aldehydes or ketones and their derivatives or substances that yield such compound on hydrolysis.
2. _________, _________, _________ & _______ are importance of carbohydrates.

• 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 the intracellular location or metabolic fate of these hybrid molecules known as GLYOCONJUGATES.

• Insoluble carbohydrate polymers serve as structural protective elements of bacterial and plant cell wall as well as connect tissues in animals.

3. Carbohydrates can be classified into ________, ________&_______. Monosaccharides, Oligosaccharides & polysaccharides.

4. Saccharide is derived from the Greek word _________. Sakcharon meaning “sugar”.

5. Monosaccharides can be sub-divided into trioses, tetroses, etc depending upon ______________. The number of carbon atoms.

6. The most abundant carbohydrate in nature is _________, sometimes referred to as ___________. •Glucose •Dextrose

7. Monosaccharides of more than four carbons tend to have cyclic structures True or False. (True)

8. How many OH groups has D- Glucose? ______ 5

9. Monosaccharides are soluble in ______ but insoluble in ________. Water & Non-polar solvents.

10. In drawing a keto group, the first and last carbon will carry different functional groups. True or False. (False)

11. Erythrose is found in synthesis of aromatic amino acid via ______________. Shikinase pathway

12, The aldo pentoses & 2- deoxyribose are components of __________&__________. Nucleotides & Nuclei acids

13.  Oligosaccharides are carbohydrates consisting of __________________. Oligosaccharides are short chains of polypeptide units (2-10 molecules) linked by a glycosidic bond. **A glycosidic bond is a covalent bond that links the hemiacetal group of a saccharide molecule and the hydroxyl (OH) group of an organic compound.

14. The most abundant Oligosaccharides are _____________ Disaccharides

15. D- Glucose + D- Glucose → __________ Maltose

16. Molecular composition of Raffinose is __________. Alpha-Galactose(1- 6), Alpha- Glucose (1-2), B- Fructose

17.  Molecular composition of Stachyose is __________. Alpha-Galactose (1-6), Alpha- Galactose (1-6), Alpha- Glucose(1-2), B- Fructose

18. Examples of homopolysaccharides are _____________________. Chitin, Inulin, Pectin, Starch, Cellulose, Glycogen.

19. Examples of heteropolysaccharides are ________________. Specific soluble sugars of pneumococcus type III, Hyaluronic acid, Chondrotin

20. Unit of chitin is ______________. N-acetylglucosamin

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PART 2

1. Which monosaccharide does not exhibit optical activity?
   • Dihydroxyacetone
2. When the hydroxyl group on a reference carbon atom is on the right in the projection formula, the sugar is a ____ isomer. When on the left, it is an _____ isomer.
   • D & L respectively
3. According to ___________ rule, the total number of optical isomers of a compound will be equal to 2ⁿ.
   • Le-Bell-Van’t Hoff rule
4. The preferred structures for monosaccharides in aqueous solution are __________ & __________.
   • Pyranose & Furanose
5. Monosaccharides that differ only in the configuration about the carbon atom and are designated as alpha or beta are known as ________.
   • Anomers
6. Mutarotation brings about the formation of a linear aldehyde or ketone. True or False?
   • TRUE
7. Alpha D-Glucose has a specific optical rotation of ____ while beta D-Glucose ______.
   • 112.2° & 18.7° respectively
8. _______ are two sugars that differ only in the configuration around one carbon atom.
   • Epimers
9. Epimer at C2 of D-Glucose is _______ while epimer at C4 is __________.
   • Mannose & Galactose respectively
10. ______________ is released during the formation of hemiacetals & hemiketals.
    • Water
11. Monosaccharides can be oxidized by _________________.
    • Ferric (Fe²⁺) & Cupric (Cu²⁺)
12. The carbonyl carbon in D-Glucose is oxidized to give ____________.
    • D-Gluconic acid
13. Qualitative test for reducing sugars can be determined using ________________.
    • Fehling’s solution
14. Which enzyme catalyzes the reaction: D-Glucose + O₂ → D-Gluconic-∆-lactone + H₂O?
    • Glucose Oxidase
15. Oxidation of D-Glucose at C1 & C6 yields ___________ & ___________ respectively.
    • D-Gluconic acid and D-Glucuronic acid
16. Oxidation of D-Glucose at both C1 & C6 yields ___________.
    • Aldaric acid (e.g., D-Glucaric acid)
17. The anomeric carbon of aldoses & ketoses also reacts with liquid ammonia to form __________________, but when the reaction is at C2 _______________ is formed.
    • Glucosylamine, Glucosamine
18. How are furfurals produced?
    • Furfurals are produced by dehydrating monosaccharides using strong mineral acids.
19. The condensation of furfurals with phenols & amines yields ______________.
    • Coloured compounds
20. Alpha D-Glucose dehydrates to form __________________.
    • Hydroxymethyl furfural
21. How are osazones formed?
    • By reacting monosaccharides with excess phenylhydrazine in slightly acidic solution at a high temperature.
22. Glucose, Mannose & Fructose give the same osazone known as ___________________.
    • Glucosazone
23. In the formation of sugar alcohols, the carbonyl group of monosaccharides undergoes ______________ reaction.
    • Reduction
24. When D-Glucose reacts with H₂ from H₂SO₄, _______ & ________ are formed.
    • D-Glucitol & L-Sorbitol
25. The sugar alcohol present in lipid is called ____________.
    • Glycerol (propan-1,2,3-triol)
26. List the importance of osazone:
    • To detect sugars in plants.
    • To differentiate between reducing and non-reducing sugars.
    • To detect reducing sugars.
27. How many percent of the human body is made up of proteins?
    • 20%
28. __________ are the building block of proteins.
    • Amino acids
29. Amino acids are linked to one another by ___________.
    • Peptide bonds
30. Define an amino acid.
    • An amino acid is a molecule containing both an amino group and an acid group.
31. __________ is the simplest amino acid.
    • Glycine
32. Side chains are denoted by the letter _____.
    • R
33. What side chain does Alanine have?
    • CH₃
34. An amino acid contains two functional groups which are ______ & _____________.
    • Carboxylic group & amino group
35. Alpha amino acids are _____________.
    • Acids that have the carboxylic & amino group attached to an alpha carbon.
36. All amino acids exhibit chirality except _________.
    • Glycine
37. An important role of non-polar amino acids is _______________.
    • To maintain the three-dimensional structure of proteins
38. Non-polar amino acids can be subdivided into ________&____.
    • Alkyl or aliphatic and aromatic non-polar amino acids
39. _____________ is a derivative of methionine. What is the importance of the named derivative?
    • S-Adenosyl methionine (SAM). It serves as a methyl donor in biochemical reactions.
40. _______, _______, & __________ amino acids contain a polar OH group that enables its participation in hydrogen bonding.
    • Serine, Threonine, and Tyrosine
41. Two cysteine molecules oxidize in the extracellular compartment to form a disulphide compound known as _______________.
    • Cystine
42. Why is Histidine classified as a weak base?
    • It is partially ionized at pH 7.
43. Differentiate between essential & non-essential amino acids.
    • Essential amino acids are needed in our diets because our bodies cannot make them, while non-essential amino acids can be synthesized by the body.
44. In an amino acid, if its carboxyl group loses a proton, thus giving a carboxylate ion, and its amino group is protonated to an ammonium ion, the new structure is known as _________________.
    • Dipolar ion or Zwitterion
45. List the acid-base properties of amino acids:
    • Have a high melting point of about 200°C.
    • Soluble in water, but insoluble in non-polar solvents such as ether and dichloromethane.

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