Q.1 Which organelle is known as the powerhouse of the cell?
Nucleus
Mitochondria
Ribosome
Endoplasmic Reticulum
Explanation - Mitochondria generate ATP through oxidative phosphorylation, providing energy for cellular processes.
Correct answer is: Mitochondria
Q.2 What is the primary function of ribosomes?
Energy production
Protein synthesis
DNA replication
Lipid storage
Explanation - Ribosomes translate mRNA into polypeptide chains, essential for protein production.
Correct answer is: Protein synthesis
Q.3 The plasma membrane is primarily composed of:
Proteins and carbohydrates
Lipids and nucleic acids
Phospholipids and proteins
DNA and RNA
Explanation - The plasma membrane is a phospholipid bilayer embedded with proteins for transport and signaling.
Correct answer is: Phospholipids and proteins
Q.4 Which cellular structure regulates the entry and exit of substances?
Nucleus
Plasma membrane
Golgi apparatus
Cytoskeleton
Explanation - The plasma membrane is selectively permeable, controlling movement of substances in and out of the cell.
Correct answer is: Plasma membrane
Q.5 Which of the following is NOT a membranous organelle?
Mitochondria
Ribosome
Lysosome
Endoplasmic Reticulum
Explanation - Ribosomes lack a membrane and are composed of RNA and proteins.
Correct answer is: Ribosome
Q.6 The rough endoplasmic reticulum is studded with:
Ribosomes
Mitochondria
DNA
Centrioles
Explanation - Rough ER has ribosomes attached for protein synthesis, distinguishing it from smooth ER.
Correct answer is: Ribosomes
Q.7 Which process describes the movement of water across a semi-permeable membrane?
Diffusion
Osmosis
Active transport
Endocytosis
Explanation - Osmosis is the passive movement of water from low to high solute concentration across a membrane.
Correct answer is: Osmosis
Q.8 Which organelle is responsible for packaging and modifying proteins?
Lysosome
Golgi apparatus
Nucleus
Mitochondria
Explanation - The Golgi apparatus modifies, sorts, and packages proteins for secretion or intracellular use.
Correct answer is: Golgi apparatus
Q.9 Which structure contains the genetic material of the cell?
Mitochondria
Ribosome
Nucleus
Golgi apparatus
Explanation - The nucleus houses DNA, which directs cellular functions via gene expression.
Correct answer is: Nucleus
Q.10 What is the main function of lysosomes?
Energy production
Protein synthesis
Digestion of cellular waste
DNA replication
Explanation - Lysosomes contain hydrolytic enzymes that break down waste materials and cellular debris.
Correct answer is: Digestion of cellular waste
Q.11 Which cellular process requires energy in the form of ATP?
Diffusion
Osmosis
Active transport
Facilitated diffusion
Explanation - Active transport moves substances against their concentration gradient, requiring ATP.
Correct answer is: Active transport
Q.12 What type of RNA carries genetic code from DNA to ribosomes?
tRNA
mRNA
rRNA
siRNA
Explanation - Messenger RNA (mRNA) carries genetic information from the nucleus to ribosomes for translation.
Correct answer is: mRNA
Q.13 Which ion is most abundant inside a resting cell?
Sodium
Potassium
Calcium
Chloride
Explanation - Potassium concentration is high inside cells, while sodium is high outside, maintaining membrane potential.
Correct answer is: Potassium
Q.14 Endocytosis refers to:
Release of substances from the cell
Uptake of materials into the cell
Production of proteins
Osmotic balance maintenance
Explanation - Endocytosis is an active process where the cell engulfs extracellular materials into vesicles.
Correct answer is: Uptake of materials into the cell
Q.15 Which protein provides structural support to the plasma membrane?
Tubulin
Actin
Collagen
Keratin
Explanation - Actin filaments form part of the cytoskeleton, supporting membrane shape and movement.
Correct answer is: Actin
Q.16 Which organelle contains its own DNA and ribosomes?
Lysosome
Mitochondria
Golgi apparatus
Rough ER
Explanation - Mitochondria have their own DNA and ribosomes, enabling synthesis of some of their proteins.
Correct answer is: Mitochondria
Q.17 Which enzyme is responsible for ATP synthesis in mitochondria?
DNA polymerase
RNA polymerase
ATP synthase
Peptidase
Explanation - ATP synthase catalyzes the production of ATP during oxidative phosphorylation.
Correct answer is: ATP synthase
Q.18 Gap junctions in cells are important for:
Cell adhesion
Electrical communication
Protein synthesis
DNA replication
Explanation - Gap junctions allow ions and small molecules to pass directly between cells, facilitating communication.
Correct answer is: Electrical communication
Q.19 Which process involves engulfing solid particles into a cell?
Pinocytosis
Phagocytosis
Exocytosis
Facilitated diffusion
Explanation - Phagocytosis is a type of endocytosis where cells engulf large particles like bacteria.
Correct answer is: Phagocytosis
Q.20 The Na+/K+ pump transports:
3 Na+ in, 2 K+ out
3 Na+ out, 2 K+ in
2 Na+ in, 2 K+ out
2 Na+ out, 3 K+ in
Explanation - The Na+/K+ pump actively transports 3 sodium ions out and 2 potassium ions in, maintaining electrochemical gradients.
Correct answer is: 3 Na+ out, 2 K+ in
Q.21 The cytoskeleton does NOT include:
Microtubules
Intermediate filaments
Actin filaments
Ribosomes
Explanation - Ribosomes are not part of the cytoskeleton; they are protein-synthesizing structures.
Correct answer is: Ribosomes
Q.22 Which organelle plays a major role in detoxification in liver cells?
Mitochondria
Smooth ER
Rough ER
Lysosomes
Explanation - Smooth ER is involved in lipid metabolism and detoxification of drugs and poisons.
Correct answer is: Smooth ER
Q.23 Which cellular junction prevents leakage of substances between epithelial cells?
Gap junction
Tight junction
Desmosome
Hemidesmosome
Explanation - Tight junctions seal neighboring cells together, preventing passage of molecules between them.
Correct answer is: Tight junction
Q.24 Which molecule is the primary energy currency of the cell?
Glucose
ATP
NADH
GTP
Explanation - ATP (adenosine triphosphate) is the universal energy carrier in cellular metabolism.
Correct answer is: ATP
Q.25 Autophagy is the process of:
Cellular protein synthesis
Digestion of own organelles
DNA repair
Exocytosis
Explanation - Autophagy is a survival mechanism where cells degrade their own damaged organelles and proteins.
Correct answer is: Digestion of own organelles