Selected MCQ

Current Question
Which organelle in animal cells contains its own circular DNA and is involved in ATP production?
  • A. Mitochondrion
  • B. Golgi apparatus
  • C. Peroxisome
  • D. Endoplasmic reticulum
Correct Answer: A
Explanation:
Mitochondria have a circular genome and produce ATP through oxidative phosphorylation.
Related Question 1
Which organelle contains hydrolytic enzymes and is involved in the degradation of cellular components during autophagy?
  • A. Lysosome
  • B. Proteasome
  • C. Golgi apparatus
  • D. Smooth endoplasmic reticulum
Correct Answer: A
Explanation:
Lysosomes contain acid hydrolases that fuse with autophagosomes to degrade cellular organelles and proteins.
Related Question 2
Which of the following organelles is present in plant cells but absent in animal cells?
  • A. Peroxisome
  • B. Centrosome
  • C. Chloroplast
  • D. Golgi apparatus
Correct Answer: C
Explanation:
Chloroplasts (sites of photosynthesis) are found in plant and algal cells but not in animal cells.
Related Question 3
Which organelle is primarily involved in the detoxification of hydrogen peroxide (H₂O₂) in eukaryotic cells?
  • A. Lysosome
  • B. Mitochondrion
  • C. Peroxisome
  • D. Golgi apparatus
Correct Answer: C
Explanation:
Peroxisomes contain the enzyme catalase, which converts H₂O₂ to water and oxygen. They specialize in detoxifying reactive oxygen species.
Related Question 4
Gap junction channels between animal cells are formed by which protein?
  • A. Connexin
  • B. Cadherin
  • C. Integrin
  • D. Actin
Correct Answer: A
Explanation:
Connexins assemble into connexons that align between adjacent cells to form gap junction channels for direct cytoplasmic communication.
Related Question 5
Which organelle is primarily responsible for lipid synthesis and detoxification of drugs in liver cells?
  • A. Rough endoplasmic reticulum
  • B. Smooth endoplasmic reticulum
  • C. Golgi apparatus
  • D. Mitochondrion
Correct Answer: B
Explanation:
Smooth ER contains enzymes involved in lipid metabolism and drug detoxification (e.g., cytochrome P450s), especially in hepatocytes.