Q11. What is the main component of the cytoskeleton?
a) Lipids
b) Nucleic acids
c) Proteins
d) Carbohydrates
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Correct Answer: c) Proteins
Explanation: The cytoskeleton is primarily made up of proteins. It provides structural support to the cell, aids in intracellular transport, and is involved in various cellular movements.
Q12. Which part of the cell cycle involves the replication of DNA?
a) G1 phase
b) S phase
c) G2 phase
d) M phase
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Correct Answer: b) S phase
Explanation: The S phase (Synthesis phase) of the cell cycle is dedicated to the replication of DNA. During this phase, each chromosome is replicated to produce two identical sister chromatids, ensuring that each new cell will receive a complete set of chromosomes.
Q13. In which cell organelle does cellular respiration occur?
a) Chloroplast
b) Ribosome
c) Mitochondria
d) Nucleus
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Correct Answer: c) Mitochondria
Explanation: Cellular respiration occurs in the mitochondria. This process converts biochemical energy from nutrients into adenosine triphosphate (ATP), and releases waste products.
Q14. What is the primary function of the Golgi apparatus?
a) Protein synthesis
b) DNA replication
c) Modifying, sorting, and packaging proteins
d) Lipid metabolism
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Correct Answer: c) Modifying, sorting, and packaging proteins
Explanation: The Golgi apparatus is primarily involved in modifying, sorting, and packaging proteins and lipids that have been synthesized in the endoplasmic reticulum. It plays a crucial role in the processing and dispatching of these substances to their correct destinations.
Q15. Which type of RNA carries amino acids to the ribosome?
a) Messenger RNA (mRNA)
b) Transfer RNA (tRNA)
c) Ribosomal RNA (rRNA)
d) MicroRNA (miRNA)
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Correct Answer: b) Transfer RNA (tRNA)
Explanation: Transfer RNA (tRNA) is responsible for carrying amino acids to the ribosome during protein synthesis. Each tRNA molecule matches an amino acid to its corresponding mRNA codon.
Q16. What is a lysosome?
a) A structure involved in protein synthesis
b) An organelle responsible for energy production
c) A membrane-bound organelle containing digestive enzymes
d) A component of the cell membrane
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Correct Answer: c) A membrane-bound organelle containing digestive enzymes
Explanation: Lysosomes are membrane-bound organelles that contain digestive enzymes. They are involved in breaking down various molecules, including worn-out cell parts, for recycling or waste disposal.
Q17. Which of the following structures is unique to animal cells?
a) Cell wall
b) Chloroplast
c) Centrioles
d) Large central vacuole
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Correct Answer: c) Centrioles
Explanation: Centrioles are unique to animal cells and are involved in cell division. They play a key role in the formation of the spindle fibers during mitosis and meiosis.
Q18. Osmosis primarily involves the movement of
a) Ions
b) Proteins
c) Water
d) Lipids
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Correct Answer: c) Water
Explanation: Osmosis is the movement of water molecules across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration. It is a crucial process in cells for maintaining fluid balance.
Q19. Which cell junctions provide channels for communication between cells?
a) Tight junctions
b) Desmosomes
c) Gap junctions
d) Plasmodesmata
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Correct Answer: c) Gap junctions
Explanation: Gap junctions provide channels that allow molecules, ions, and electrical impulses to pass directly from one cell to another, facilitating intercellular communication. They are essential for many cellular processes, including coordinated responses in tissues.
Q20. Which process involves the division of a cell’s nucleus and its genetic material?
a) Cytokinesis
b) Mitosis
c) Meiosis
d) Binary fission
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Correct Answer: b) Mitosis
Explanation: Mitosis is the process where a cell divides its nucleus and genetic material into two equal sets. It is a part of the cell cycle in eukaryotic cells that leads to the production of two daughter cells with identical genetic material.