Membrane cell organelles: species, structure, functions

Cells of animals, plants and fungi consist of three main parts: the plasma membrane, the nucleus and the cytoplasm. Bacteria differ from them in that they do not have a nucleus, but they also have a membrane and a cytoplasm.

How is the cytoplasm?

This is the inner part of the cell, in which it is possible to isolate the hyaloplasm (liquid medium), inclusions and organelles (organelles). Inclusions are unstable formations in the cell, which are mostly drops or crystals of reserve nutrients. Organoids are permanent structures. As in the body the main functional units are the organs, so in the cell all the basic functions are performed by the organelles.

Membrane and non-membrane organelle cells

The former are divided into single-membrane and double-membrane. Only the last two are mitochondria and chloroplasts. One-membrane ones include lysosomes, Golgi complex, endoplasmic reticulum (endoplasmic reticulum), vacuoles. We will talk in detail about non-membrane organoids in this article.

Cellular organoids of a non-membrane structure

These include the ribosomes, the cell center, as well as the cytoskeleton formed by microtubules and microfilaments. Also to this group can be considered the organoids of movement, which have unicellular organisms, as well as male sex cells of animals. Let's look at the order of non-membrane organoids of the cell, their structure and functions.

What are ribosomes?

These are non-membrane organelles of the cell, which consist of ribonucleoproteins. Their structure includes two parts (subunits). One of them is small, one is big. In a calm state they are separated. They are connected when the ribosome begins to function.

These non-membrane organoids of the cell respond for the synthesis of proteins. Namely, for the translation process - the combination of amino acids in the polypeptide chain in a certain order, information about which is copied from DNA and recorded on the mRNA.

The size of the ribosomes is twenty nanometers. The number of these organoids in a cell can reach up to several tens of thousands of pieces.

In eukaryotes, ribosomes are found both in the hyaloplasm and on the surface of the rough endoplasmic reticulum. They are also present inside the two-membrane organoids: mitochondria and chloroplasts.

Cellular Center

This organoid consists of a centrosome, which is surrounded by a centrosphere. The centrosome is represented by two centrioles - empty inside the cylinders, consisting of microtubules. The centrosphere consists of radially microtubules leaving the cell center. It also includes intermediate filaments and microfibrils.

The cell center performs such functions as the formation of the spindle of division. It is also the center of microtubule organization.

As for the chemical structure of this organoid, the main substance is the protein tubulin.

This organoid is in the geometric center of the cell, so it has this name.

Microfilaments and microtubules

The first are threads from the actin protein. Their diameter is 6 nanometers.

The diameter of microtubules is 24 nanometers. Their walls are constructed of tubulin protein.

These non-membrane organelles form a cytoskeleton that helps maintain a constant shape.

Another function of microtubules is transport, and organelles and substances in the cell can travel through them.

Organoids of movement

They are of two types: cilia and flagella.

The first to have such single-celled organisms, as infusoria-shoes.

Flagellum is found in chlamydomonads, as well as in spermatozoa of animals.

Organoids of movement consist of contractile proteins.

Conclusion

As an output, we give generalized information.

So we examined all the non-membrane organelles of plants, animals, fungi and bacteria, their structure and functions.