Non-membrane bound cell organelles

Non-membrane bound cell organelles are those organelles that are not surrounded by a membrane and are found in both prokaryotic and eukaryotic cells. These organelles perform various functions in the cell.

Examples of non-membrane bound cell organelles

Some of the examples of non-membrane bound cell organelles are:

- Ribosomes
- Centrioles
- Nucleolus

Explanation

Ribosomes

Ribosomes are non-membrane bound cell organelles that are responsible for protein synthesis. They are made up of RNA and protein molecules. Ribosomes are found in both prokaryotic and eukaryotic cells. In eukaryotic cells, they are found free in the cytoplasm or attached to the endoplasmic reticulum.

Centrioles

Centrioles are also non-membrane bound cell organelles that are found in animal cells. They are involved in cell division and help in the formation of spindle fibers during cell division. Centrioles are made up of microtubules and are found in pairs.

Nucleolus

The nucleolus is a non-membrane bound cell organelle found in the nucleus of eukaryotic cells. It is involved in the synthesis of ribosomal RNA (rRNA) and the assembly of ribosomes. The nucleolus is made up of proteins, DNA, and RNA molecules.

All of these

All the given options, i.e., ribosomes, centrioles, and nucleolus, are non-membrane bound cell organelles. Therefore, the correct answer is option D, i.e., all of these.