MCQs on Biomolecules & Enzymes for ICAR (SRF or JRF) /ASRB /CSIR NET/BET Exams #1

1. Which of the following is a carbohydrate but not a polymer?
   (A) Glucose
   (B) Starch
   (C) Cellulose
   (D) Chitin

2. Based on molecular formula, which of the following is a monosaccharide?
   (A) C18H36O18
   (B) C18H32O16
   (C) C6H10O5
   (D) C3H6O3

3. If two molecules of glucose were joined together, the disaccharide is called:
   (A) Maltose
   (B) Fructose
   (C) Glucose
   (D) Galactose

4. All of the following are polysaccharides except:
   (A) Maltose
   (B) Glycogen
   (C) Chitin
   (D) Cellulose

5. Which of the following is true of both starch and cellulose?
   (A) They are both polymers of glucose
   (B) Their glucoses all have the same orientation
   (C) They can both be digested by humans
   (D) They are both used for energy storage in plants

6. Which of the following statements is true for all lipids?
   (A) They are hydrophobic
   (B) They are made from glycerol, fatty acids, and phosphate
   (C) They contain less energy than proteins and carbohydrates
   (D) They are made by dehydration reactions

7. Which statement concerning saturated fatty acids is not true?
   (A) They are more common in animals than in plants
   (B) They have double bonds in the carbon chain of the fatty acid
   (C) At room temperature, they are more viscous (solid) than unsaturated fatty acids
   (D) They contain more hydrogen than unsaturated fats with the same number of carbon atoms

8. Which of the following statements are true? (More than one correct answer)
   (A) It is an unsaturated fatty acid
   (B) A diet rich in this molecule may contribute to atherosclerosis
   (C) Molecules of this type are usually liquid at room temperature
   (D) It is an unsaturated fatty acid and a diet rich in this molecule may contribute to atherosclerosis

9. Which of the following is a lipid that does not contain glycerol and fatty acid monomers?
   (A) Steroids
   (B) Saturated fats
   (C) Unsaturated fats
   (D) Triglycerides

10. Human sex hormones (e.g., estrogen and testosterone) are this type of lipid:
    (A) Steroids
    (B) Saturated fats
    (C) Unsaturated fats
    (D) Triglycerides

11. All of the following are proteins except:
    (A) Enzymes
    (B) Receptors
    (C) Channel proteins
    (D) Cellulose

12. The bonding of two amino acid molecules to form a larger molecule requires:
    (A) The release of a water molecule
    (B) The release of a carbon dioxide molecule
    (C) The addition of a nitrogen atom
    (D) The addition of a water molecule

13. There are 20 different amino acids. What makes one amino acid different from another?
    (A) Different side chains (R groups) attached to a carboxylic acid carbon
    (B) Different side chains (R groups) attached to the amino group
    (C) Different side chains (R groups) attached to the central carbon
    (D) Different arrangement of the amine and the carboxylic acid functional groups

14. A polypeptide containing 100 amino acids has how many peptide bonds?
    (A) 101
    (B) 100
    (C) 99
    (D) 98

15. Which aspects of protein structure are stabilized or assisted by hydrogen bonds?
    (A) Primary structure
    (B) Secondary structure
    (C) Tertiary structure
    (D) Secondary, tertiary, and quaternary structures, but not primary structure

16. What type of covalent bond between amino acid side chains functions in maintaining a polypeptide's 3D shape?
    (A) Ionic bond
    (B) Hydrophobic interaction
    (C) Van der Waals interaction
    (D) Disulfide bond

17. The difference between the sugar in DNA and RNA is that DNA sugar:
    (A) Is a six-carbon sugar and RNA sugar is a five-carbon sugar
    (B) Can form a double-stranded molecule
    (C) Is an aldehyde sugar and RNA sugar is a keto sugar
    (D) Contains one less oxygen atom

18. Which description best fits nucleotides?
    (A) A nitrogenous base and a phosphate group
    (B) A nitrogenous base and a ribose sugar
    (C) A nitrogenous base, a phosphate group, and a ribose sugar
    (D) A phosphate group and an adenine or uracil

19. Which are nitrogenous bases of the pyrimidine type?
    (A) Guanine and adenine
    (B) Cytosine and uracil
    (C) Thymine and guanine
    (D) Ribose and deoxyribose

20. If a DNA sample has 10% thymine, what is the percentage of guanine?
    (A) 10%
    (B) 20%
    (C) 40%
    (D) 80%

21. If cytosine makes up 42% of nucleotides in DNA, the approximate percentage of thymine is:
    (A) 8%
    (B) 16%
    (C) 31%
    (D) 42%

22. Which of the following is most similar in structure to ATP?
    (A) A ribose sugar
    (B) A DNA nucleotide
    (C) An RNA nucleotide
    (D) An amino acid with three phosphate groups attached

23. Why is ATP important in metabolism?
    (A) It removes toxins by binding to them
    (B) It provides energy for cellular reactions
    (C) It is very stable and stabilizes other molecules
    (D) It is one of the four building blocks for RNA synthesis

24. What is the difference between ATP and an RNA A nucleotide?
    (A) The sugar molecule is different
    (B) The nitrogen-containing base is different
    (C) The number of phosphates is three instead of one
    (D) The number of phosphates is three instead of two

25. If cells are grown in a medium with radioactive phosphate, which molecules become radioactive?
    (A) Phospholipids
    (B) Nucleic acids
    (C) Proteins
    (D) Both phospholipids and nucleic acids