Choose the incorrect statement w.r.t ribosome.

Options

A. It is composed of rRNA and proteins
B. It is not surrounded by any membrane
C. It is the smallest cell organelle
D. It helps in lipid synthesis

Answer

To determine the incorrect statement regarding ribosomes, we will analyze each option provided.

### Step-by-Step Solution:

1. **Understanding Ribosome Composition**:
- Ribosomes are indeed composed of ribosomal RNA (rRNA) and proteins. They are classified into two types based on their sedimentation rates: 70S (found in prokaryotes) and 80S (found in eukaryotes).
- **Hint**: Remember that ribosomes consist of rRNA and proteins, and they come in two main types based on their size.

2. **Membrane Structure**:
- Ribosomes are not surrounded by any membrane; they are considered membrane-less organelles. This statement is correct.
- **Hint**: Think about the structural characteristics of ribosomes and how they differ from other organelles.

3. **Size Comparison**:
- Ribosomes are often referred to as the smallest cell organelles. This statement is also accurate.
- **Hint**: Recall the relative sizes of various organelles to confirm which is the smallest.

4. **Function of Ribosomes**:
- The primary function of ribosomes is protein synthesis. They do not play a role in lipid synthesis; that function is performed by the smooth endoplasmic reticulum (SER).
- **Hint**: Focus on the main functions of ribosomes and compare them to other organelles like the smooth endoplasmic reticulum.

### Conclusion:
Based on the analysis:
- The incorrect statement is: "It helps in lipid synthesis." Ribosomes are involved in protein synthesis, not lipid synthesis. Therefore, the correct answer is option 4.

### Final Answer:
The incorrect statement with respect to ribosomes is that they help in lipid synthesis.