Q21. Which organelle is responsible for regulating what enters and exits the cell in both plant and animal cells?
a) Nucleus
b) Endoplasmic reticulum
c) Golgi apparatus
d) Cell membrane
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Correct Answer: d) Cell membrane
Explanation: The cell membrane, also known as the plasma membrane, regulates the passage of molecules into and out of the cell. It is selectively permeable, allowing some substances to pass while blocking others, and is essential for maintaining cellular homeostasis.
Q22. Which structure is responsible for the synthesis of ribosomal RNA (rRNA) and assembly of ribosomal subunits in both plant and animal cells?
a) Nucleus
b) Nucleolus
c) Golgi apparatus
d) Mitochondrion
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Correct Answer: b) Nucleolus
Explanation: The nucleolus is a substructure within the nucleus where ribosomal RNA (rRNA) is synthesized and ribosomal subunits are assembled. These subunits combine with proteins to form functional ribosomes involved in protein synthesis.
Q23. Which organelle is responsible for breaking down cellular waste and foreign materials in both plant and animal cells?
a) Lysosome
b) Peroxisome
c) Mitochondrion
d) Golgi apparatus
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Correct Answer: a) Lysosome
Explanation: Lysosomes are membrane-bound organelles containing digestive enzymes that break down cellular waste materials, old organelles, and foreign particles. They play a crucial role in cellular recycling and waste management.
Q24. What is the function of the endoplasmic reticulum (ER) in both plant and animal cells?
a) Protein synthesis
b) Lipid synthesis
c) Cellular respiration
d) Photosynthesis
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Correct Answer: a) Protein synthesis
Explanation: The endoplasmic reticulum (ER) is involved in protein synthesis and modification. Rough ER, studded with ribosomes, synthesizes proteins that are destined for secretion or insertion into membranes, while smooth ER is involved in lipid synthesis and detoxification.
Q25. Which structure is responsible for maintaining turgor pressure and storing water, nutrients, and pigments in plant cells?
a) Central vacuole
b) Nucleus
c) Chloroplast
d) Mitochondrion
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Correct Answer: a) Central vacuole
Explanation: The central vacuole is a large, membrane-bound organelle found in plant cells that stores water, nutrients, ions, pigments, and waste products. It helps maintain turgor pressure, which is essential for cell rigidity and plant growth.
Q26. Which organelle is responsible for producing ATP through cellular respiration in both plant and animal cells?
a) Chloroplast
b) Golgi apparatus
c) Mitochondrion
d) Endoplasmic reticulum
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Correct Answer: c) Mitochondrion
Explanation: Mitochondria are membrane-bound organelles responsible for generating energy in the form of ATP through cellular respiration. They are often referred to as the “powerhouses” of the cell and are present in both plant and animal cells.
Q27. Which structure is involved in packaging and transporting proteins for secretion in both plant and animal cells?
a) Nucleus
b) Endoplasmic reticulum
c) Golgi apparatus
d) Lysosome
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Correct Answer: c) Golgi apparatus
Explanation: The Golgi apparatus, or Golgi complex, is involved in the modification, sorting, and packaging of proteins and lipids for secretion or delivery to other organelles. It receives proteins from the endoplasmic reticulum and modifies them before distributing them to their final destinations.
Q28. What is the function of the cell wall in plant cells?
a) Regulation of cellular processes
b) Protection against mechanical stress
c) Synthesis of proteins
d) Energy production
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Correct Answer: b) Protection against mechanical stress
Explanation: The cell wall is a rigid structure found outside the plasma membrane of plant cells. It provides structural support, protection against mechanical stress, and helps maintain cell shape. It also prevents excessive water uptake.
Q29. Which organelle is responsible for photosynthesis in plant cells?
a) Nucleus
b) Golgi apparatus
c) Chloroplast
d) Lysosome
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Correct Answer: c) Chloroplast
Explanation: Chloroplasts are organelles found in plant cells responsible for photosynthesis. They contain chlorophyll, a pigment that captures light energy from the sun and converts it into chemical energy in the form of glucose.
Q30. Which structure contains the genetic material (DNA) and controls cellular activities in both plant and animal cells?
a) Nucleus
b) Ribosome
c) Endoplasmic reticulum
d) Golgi apparatus
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Correct Answer: a) Nucleus
Explanation: The nucleus is a membrane-bound organelle that contains the cell’s genetic material (DNA) and controls cellular activities such as growth, metabolism, and reproduction. It is present in both plant and animal cells.