Find the correct set of structures `//` organelles not s urrounded by membrane

Options

A. Ribosomes , centrosome , lysosome
B. Peroxisome, nucelous , centriole
C. Ribosome , nucleolus , centriole
D. Nucleolus , spherosome , ribsosome

Answer

To find the correct set of structures or organelles that are not surrounded by a membrane, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: We need to identify organelles that do not have a surrounding membrane. Membrane-bound organelles include structures like lysosomes, peroxisomes, and others that are enclosed by lipid bilayers.

2. **Identify Non-Membrane Bound Organelles**:
- **Ribosomes**: These are the sites of protein synthesis and are not surrounded by any membrane. They exist as free ribosomes in the cytoplasm or bound to the endoplasmic reticulum.
- **Cytoskeletal Structures**: These include microtubules, microfilaments, and intermediate filaments, which provide structural support and are not membrane-bound.
- **Centrioles**: These are cylindrical structures involved in cell division and are also not surrounded by a membrane.
- **Basal Bodies**: These are similar to centrioles and are involved in the formation of cilia and flagella, and they lack a surrounding membrane.
- **Cilia and Flagella**: These are hair-like structures that protrude from the cell surface and assist in movement. They are not membrane-bound.

3. **Evaluate the Options**: If given a set of options, we should check each one to see if they are membrane-bound or not. For instance:
- **Nucleolus**: This structure is found within the nucleus, which is double-membraned. However, the nucleolus itself is not membrane-bound.
- **Peroxisomes and Lysosomes**: Both of these organelles are membrane-bound, so they would not be included in the correct set.

4. **Conclusion**: The correct set of organelles that are not surrounded by a membrane includes ribosomes, cytoskeletal structures, centrioles, basal bodies, cilia, and flagella. The nucleolus can also be included as it is not membrane-bound despite being located within the nucleus.

### Final Answer:
The correct set of organelles not surrounded by a membrane includes:
- Ribosomes
- Cytoskeletal structures
- Centrioles
- Basal bodies
- Cilia and flagella
- Nucleolus