Q.1 Which organelle is known as the powerhouse of the cell?
Nucleus
Mitochondria
Ribosome
Endoplasmic Reticulum
Explanation - Mitochondria generate ATP through cellular respiration, providing energy for the cell.
Correct answer is: Mitochondria
Q.2 Which of the following is a function of ribosomes?
Protein synthesis
Lipid synthesis
Energy production
Detoxification
Explanation - Ribosomes are responsible for translating mRNA into polypeptide chains, forming proteins.
Correct answer is: Protein synthesis
Q.3 The plasma membrane is primarily composed of:
Proteins only
Lipids only
Carbohydrates only
Lipids and proteins
Explanation - The plasma membrane consists of a lipid bilayer embedded with proteins that regulate transport and signaling.
Correct answer is: Lipids and proteins
Q.4 Which cell organelle contains hydrolytic enzymes and is involved in intracellular digestion?
Golgi apparatus
Lysosome
Nucleus
Peroxisome
Explanation - Lysosomes contain digestive enzymes that break down macromolecules, old organelles, and pathogens.
Correct answer is: Lysosome
Q.5 Which structure is responsible for modifying, sorting, and packaging proteins and lipids?
Endoplasmic Reticulum
Golgi apparatus
Ribosome
Vacuole
Explanation - The Golgi apparatus receives proteins from the ER, modifies them, and sends them to their destination.
Correct answer is: Golgi apparatus
Q.6 Which component of the cytoskeleton helps in cell division and intracellular transport?
Microtubules
Microfilaments
Intermediate filaments
Centrosomes
Explanation - Microtubules form the mitotic spindle during cell division and provide tracks for organelle movement.
Correct answer is: Microtubules
Q.7 Which organelle is absent in mature red blood cells?
Nucleus
Mitochondria
Ribosome
All of the above
Explanation - Mature RBCs lose their nucleus, mitochondria, and ribosomes to maximize space for hemoglobin.
Correct answer is: All of the above
Q.8 Which cell type has a cell wall made of chitin?
Plant cells
Animal cells
Fungal cells
Bacterial cells
Explanation - Fungi have cell walls composed of chitin, whereas plants have cellulose and bacteria have peptidoglycan.
Correct answer is: Fungal cells
Q.9 Peroxisomes are primarily involved in:
Detoxification of harmful substances
Protein synthesis
Energy production
DNA replication
Explanation - Peroxisomes contain enzymes like catalase to break down hydrogen peroxide and other toxins.
Correct answer is: Detoxification of harmful substances
Q.10 Which structure acts as a selective barrier, controlling the entry and exit of substances in a cell?
Cytoplasm
Plasma membrane
Cell wall
Nucleus
Explanation - The plasma membrane is selectively permeable, regulating transport of ions, nutrients, and waste.
Correct answer is: Plasma membrane
Q.11 Which organelle is the site of lipid synthesis?
Rough ER
Smooth ER
Golgi apparatus
Mitochondria
Explanation - Smooth ER synthesizes lipids and steroids, and also detoxifies drugs in liver cells.
Correct answer is: Smooth ER
Q.12 Which part of the nucleus is responsible for ribosome synthesis?
Nuclear envelope
Nucleolus
Chromatin
Nuclear pore
Explanation - The nucleolus assembles ribosomal RNA and combines it with proteins to form ribosomal subunits.
Correct answer is: Nucleolus
Q.13 The fluid mosaic model describes the structure of:
Nuclear membrane
Cell wall
Plasma membrane
Ribosome
Explanation - The fluid mosaic model depicts the plasma membrane as a fluid lipid bilayer with embedded proteins that move laterally.
Correct answer is: Plasma membrane
Q.14 Which organelle is responsible for photosynthesis in plant cells?
Mitochondria
Chloroplast
Peroxisome
Golgi apparatus
Explanation - Chloroplasts contain chlorophyll which captures light energy to convert CO₂ and H₂O into glucose and oxygen.
Correct answer is: Chloroplast
Q.15 Which of the following is NOT part of the endomembrane system?
Golgi apparatus
Lysosome
Mitochondria
Endoplasmic reticulum
Explanation - The endomembrane system includes ER, Golgi, lysosomes, and vesicles, but mitochondria are independent organelles.
Correct answer is: Mitochondria
Q.16 Which organelle stores water, salts, and waste in plant cells?
Vacuole
Lysosome
Golgi apparatus
Ribosome
Explanation - Plant cells have a large central vacuole that stores water, ions, and metabolic waste.
Correct answer is: Vacuole
Q.17 Which of the following structures is unique to prokaryotic cells?
Nucleus
Plasmid
Mitochondria
Endoplasmic reticulum
Explanation - Plasmids are small, circular DNA molecules found in prokaryotes, separate from chromosomal DNA.
Correct answer is: Plasmid
Q.18 Which organelle helps in detoxification of alcohol in liver cells?
Smooth ER
Rough ER
Mitochondria
Golgi apparatus
Explanation - Smooth ER contains enzymes for detoxifying chemicals, including alcohol and drugs, in liver cells.
Correct answer is: Smooth ER
Q.19 Which cellular organelle is involved in apoptosis or programmed cell death?
Lysosome
Mitochondria
Golgi apparatus
Ribosome
Explanation - Mitochondria release cytochrome c to trigger the apoptotic pathway when the cell is damaged.
Correct answer is: Mitochondria
Q.20 Which type of RNA carries the genetic code from DNA to the ribosome?
rRNA
tRNA
mRNA
snRNA
Explanation - mRNA is transcribed from DNA and carries the genetic information to ribosomes for protein synthesis.
Correct answer is: mRNA
Q.21 Which of the following is NOT found in a typical animal cell?
Cell wall
Plasma membrane
Mitochondria
Nucleus
Explanation - Animal cells lack a rigid cell wall; they only have a flexible plasma membrane.
Correct answer is: Cell wall
Q.22 Which structure anchors the nucleus and organizes microtubules during cell division?
Centrosome
Golgi apparatus
Endoplasmic reticulum
Peroxisome
Explanation - The centrosome contains centrioles that organize microtubules and help in spindle formation during mitosis.
Correct answer is: Centrosome
Q.23 Which organelle produces ATP by oxidative phosphorylation?
Ribosome
Mitochondria
Chloroplast
Nucleus
Explanation - Mitochondria use the electron transport chain and oxidative phosphorylation to produce ATP.
Correct answer is: Mitochondria
Q.24 Which organelle is responsible for folding and quality control of proteins?
Rough ER
Smooth ER
Golgi apparatus
Ribosome
Explanation - Rough ER, studded with ribosomes, assists in protein folding, modification, and quality control.
Correct answer is: Rough ER
Q.25 Which organelle contains its own DNA and is semi-autonomous?
Ribosome
Mitochondria
Lysosome
Golgi apparatus
Explanation - Mitochondria have their own circular DNA and ribosomes, enabling them to produce some of their proteins independently.
Correct answer is: Mitochondria