Question

Choose the correct statements regarding cell organelles and their inclusions.
A. The endomembrane system includes Golgi complex, endoplasmic reticulum and mitochondria.
B. Rough endoplasmic reticulum bears ribosomes on its surface.
C. Both mitochondria and plastids have circular DNA.
D. A network of microtubules, microfilaments and intermediate filaments present in the cytoplasm is called cytoskeleton.
E. Mitochondrion is a single membrane-bound structure.
Choose the correct answer from the options given below :

• A. A, B and C only
• B. A and B only
• C. C, D and E only
• D. B, C and D only

Hint:

Logic Tip: The Endomembrane system acronym: \textbf{GERL-V} (Golgi, ER, Lysosome, Vacuole). Mitochondria are independent powerhouses, not part of this coordinated factory line. Knowing A is false eliminates options 1 and 2.

Answer 1

The Correct Option is D

Step 1 : Understanding the Question:
This question requires us to verify several statements regarding the structure and classification of eukaryotic cell organelles, specifically the endomembrane system, the endoplasmic reticulum, the genetic material of semiautonomous organelles, and the cytoskeleton.
Step 2 : Key Formulas and Approach:
The approach involves cross-referencing each statement with established cell biology principles:
1. Endomembrane system: Includes coordinated organelles like ER, Golgi, Lysosomes, and Vacuoles.
2. RER: Characterized by the attachment of ribosomes.
3. Organelle DNA: Semiautonomous organelles (Mitochondria and Plastids).
4. Cytoskeleton: Composed of various proteinaceous filaments.
5. Membrane structure: Differentiating between single and double-membrane organelles.
Step 3 : Detailed Explanation:

Statement A: The endomembrane system refers to a group of organelles whose functions are physically and chemically coordinated. This includes the ER, Golgi complex, Lysosomes, and Vacuoles. Mitochondria are not part of this system because their functions are independent and not coordinated with these other organelles. Thus, this statement is incorrect.

Statement B: The part of the endoplasmic reticulum that has ribosomes attached to its outer (cytoplasmic) surface is known as the Rough Endoplasmic Reticulum (RER). These ribosomes are responsible for the "rough" appearance and the synthesis of proteins. This statement is correct.

Statement C: Based on the endosymbiotic theory, both mitochondria and plastids (like chloroplasts) were once independent prokaryotic organisms. Consequently, they both contain their own genetic material, which is organized as a single circular DNA molecule. This statement is correct.

Statement D: The cytoplasm contains an elaborate network of filamentous proteinaceous structures made of microtubules, microfilaments, and intermediate filaments. This total framework is referred to as the cytoskeleton. This statement is correct.

Statement E: Mitochondria are specialized organelles that are bound by two membranes (double-membrane bound)—an outer membrane and a highly folded inner membrane (cristae). They are not single-membrane bound. Thus, this statement is incorrect.

Step 4 : Final Answer:
Upon evaluation, statements B, C, and D are factually correct, while A and E are inaccurate. Therefore, the correct option is (D).