Question

Non membrane bound cell organelles present in animal cells I. Ribosomes II. Vacuole III. Centriole IV. Lysosome

• A. I and II only
• B. II and III only
• C. III and IV only
• D. I and III only

Hint:

Ribosomes and centrioles are non-membranous organelles, whereas lysosomes, vacuoles, mitochondria and ER are membrane-bound.

Answer 1

The Correct Option is D

Concept: Cell organelles may be membrane-bound or non-membrane-bound depending upon whether they are surrounded by a lipid membrane. Understanding this distinction is important in cell biology.

Step 1: Examine Ribosomes. Ribosomes are composed of rRNA and proteins. They are not enclosed by any membrane. Therefore ribosomes are non-membrane-bound organelles.

Step 2: Examine Vacuoles. Vacuoles are enclosed by a membrane called tonoplast. Hence they are membrane-bound structures.

Step 3: Examine Centrioles. Centrioles are cylindrical microtubular structures. They are not surrounded by membranes. Therefore they are non-membrane-bound organelles.

Step 4: Examine Lysosomes. Lysosomes possess a single membrane enclosing hydrolytic enzymes. Hence they are membrane-bound organelles.

Step 5: Final conclusion. The non-membrane-bound organelles are: \[ I \text{ and } III \] Therefore option (D) is correct.