LUMS LCAT Chemistry Macromolecules — Set 3

Macromolecules MCQs set 3 for LUMS LCAT Chemistry — 20 solved questions.

LUMS LCAT Chemistry Macromolecules — Set 3

  1. Question 1

    Q1. Which of the following is a characteristic of a polysaccharide?

    • A) Soluble in water
    • B) High molecular weight
    • C) Repeating units of monosaccharides
    • D) All of the above

    Answer: All of the above

    Explanation: Polysaccharides are complex carbohydrates composed of repeating units of monosaccharides, often exhibiting high molecular weight and varying solubility in water.

  2. Question 2

    Q2. Which of the following statements is true about the structure of DNA?

    • A) It is a single-stranded molecule
    • B) It is a double-stranded molecule with sugar-phosphate backbone
    • C) It contains the base uracil
    • D) It is found in the cytoplasm

    Answer: It is a double-stranded molecule with sugar-phosphate backbone

    Explanation: DNA is a double-stranded molecule with a sugar-phosphate backbone, where the sugar is deoxyribose and the bases are A, C, G, and T.

  3. Question 3

    Q3. Which enzyme is responsible for unwinding DNA during replication?

    • A) Helicase
    • B) Topoisomerase
    • C) Primase
    • D) DNA polymerase

    Answer: Helicase

    Explanation: Helicase unwinds the double helix, creating a replication fork where DNA synthesis occurs.

  4. Question 4

    Q4. What is the role of topoisomerase in DNA replication?

    • A) To unwind DNA
    • B) To synthesize new DNA strands
    • C) To relieve torsional stress
    • D) To proofread DNA

    Answer: To relieve torsional stress

    Explanation: Topoisomerase relieves torsional stress in DNA by cutting and rejoining the DNA strands, allowing replication to proceed.

  5. Question 5

    Q5. Which of the following is a type of RNA involved in the regulation of gene expression?

    • A) mRNA
    • B) tRNA
    • C) rRNA
    • D) miRNA

    Answer: miRNA

    Explanation: miRNA (microRNA) is a type of small RNA that regulates gene expression by binding to complementary mRNA, preventing its translation.

  6. Question 6

    Q6. What is the term for the process by which a cell becomes specialized?

    • A) Differentiation
    • B) Proliferation
    • C) Apoptosis
    • D) Mutation

    Answer: Differentiation

    Explanation: Differentiation is the process by which a cell becomes specialized in structure and function to perform a specific role.

  7. Question 7

    Q7. Which of the following statements is true about glycoproteins?

    • A) They contain only carbohydrate
    • B) They contain only protein
    • C) They contain both carbohydrate and protein
    • D) They are not found in cell membranes

    Answer: They contain both carbohydrate and protein

    Explanation: Glycoproteins are molecules that contain both carbohydrate and protein components, often playing roles in cell signaling and recognition.

  8. Question 8

    Q8. What is the function of the carbohydrate component in glycoproteins?

    • A) To provide structural support
    • B) To facilitate cell signaling
    • C) To store energy
    • D) To catalyze reactions

    Answer: To facilitate cell signaling

    Explanation: The carbohydrate component in glycoproteins often plays a role in cell signaling, recognition, and adhesion.

  9. Question 9

    Q9. Which of the following is an example of a glycolipid?

    • A) Cholesterol
    • B) Phospholipid
    • C) Glycosphingolipid
    • D) Triacylglycerol

    Answer: Glycosphingolipid

    Explanation: Glycosphingolipids are a type of glycolipid that contains a carbohydrate component attached to a lipid molecule, often playing roles in cell signaling.

  10. Question 10

    Q10. Which type of bond is responsible for the formation of a polysaccharide?

    • A) Peptide bond
    • B) Glycosidic bond
    • C) Hydrogen bond
    • D) Ionic bond

    Answer: Glycosidic bond

    Explanation: Glycosidic bonds link monosaccharides together to form polysaccharides, involving the loss of a water molecule.

  11. Question 11

    Q11. Which macromolecule is composed of nucleotides?

    • A) Protein
    • B) Carbohydrate
    • C) Nucleic acid
    • D) Lipid

    Answer: Nucleic acid

    Explanation: Nucleic acids, such as DNA and RNA, are composed of nucleotides, which consist of a sugar, phosphate, and nitrogenous base.

  12. Question 12

    Q12. What is the role of the sugar molecule in a nucleotide?

    • A) To provide energy
    • B) To form the backbone of nucleic acids
    • C) To carry genetic information
    • D) To catalyze reactions

    Answer: To form the backbone of nucleic acids

    Explanation: The sugar molecule, either ribose or deoxyribose, forms part of the backbone of nucleic acids, linking to phosphate groups.

  13. Question 13

    Q13. Which polysaccharide serves as energy storage in animals?

    • A) Cellulose
    • B) Starch
    • C) Glycogen
    • D) Chitin

    Answer: Glycogen

    Explanation: Glycogen is a complex carbohydrate stored in animal livers and muscles, serving as a readily mobilizable energy reserve.

  14. Question 14

    Q14. What type of bond links amino acids together?

    • A) Glycosidic bond
    • B) Peptide bond
    • C) Hydrogen bond
    • D) Disulfide bond

    Answer: Peptide bond

    Explanation: Peptide bonds are formed between the carboxyl group of one amino acid and the amino group of another, linking them together.

  15. Question 15

    Q15. What is the term for the 3D structure of a protein?

    • A) Primary structure
    • B) Secondary structure
    • C) Tertiary structure
    • D) Quaternary structure

    Answer: Tertiary structure

    Explanation: Tertiary structure refers to the overall 3D conformation of a protein, resulting from interactions between amino acids and secondary structures.

  16. Question 16

    Q16. Which of the following is NOT a function of proteins?

    • A) Catalyzing metabolic reactions
    • B) Replicating DNA
    • C) Providing structural support
    • D) Storing genetic information

    Answer: Storing genetic information

    Explanation: Proteins perform a wide range of functions, but storing genetic information is the role of nucleic acids, not proteins.

  17. Question 17

    Q17. What is the name of the process by which cells take in macromolecules?

    • A) Endocytosis
    • B) Exocytosis
    • C) Phagocytosis
    • D) Pinocytosis

    Answer: Endocytosis

    Explanation: Endocytosis is the process by which cells internalize macromolecules and particles from outside the cell, often through vesicle formation.

  18. Question 18

    Q18. Which type of RNA carries amino acids to the ribosome?

    • A) mRNA
    • B) tRNA
    • C) rRNA
    • D) snRNA

    Answer: tRNA

    Explanation: tRNA molecules carry specific amino acids to the ribosome, where they are linked into a growing protein chain during translation.

  19. Question 19

    Q19. Which level of protein structure involves multiple polypeptide chains?

    • A) Primary
    • B) Secondary
    • C) Tertiary
    • D) Quaternary

    Answer: Quaternary

    Explanation: Quaternary structure refers to the arrangement of multiple polypeptide chains in a protein, describing how they interact and assemble.

  20. Question 20

    Q20. Which macromolecule is a major component of cell membranes?

    • A) Protein
    • B) Carbohydrate
    • C) Nucleic acid
    • D) Lipid

    Answer: Lipid

    Explanation: Lipids, particularly phospholipids, are key components of cell membranes, forming the bilayer structure that encapsulates cells.