Membranous Organelles vs. Nonmembranous Organelles
Key Differences
Comparison Chart
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Function
In Prokaryotes
Fluid-Filled Organelles
Definite Boundary
Presence
Enclosed by a Membrane
Examples
Membranous Organelles vs. Nonmembranous Organelles
Membranous organelles are those organelles which normally bounded by a single or double plasma membrane to separate the organelles’ fluid-filled spaces; on the other hand, nonmembranous organelles are those organelles which do not consist of any bounded plasma membrane for separating the organelles from the cell cytoplasm. All prokaryotes do not consist of any membranous organelles, while all prokaryotic organelles are nonmembranous organelles.
The membranous organelles consist of fluid-filled cavities inside the organelle; on the other hand, all nonmembranous organelles do not consist of any fluid-filled cavities inside the organelles. A definite boundary is given to the organelles, which are membranous organelles; on the flip side, the nonmembranous organelles are incessant with the cytoplasm.
The membranous organelles are only present in eukaryotic cells; on the contrary, the nonmembranous organelles are present in both prokaryotic and eukaryotic cells. Various examples of membranous organelles are endoplasmic reticulum, mitochondria, nucleus, Golgi apparatus, Golgi complex, Golgi vesicles, secretory vesicles, plastids, peroxisomes, phagosomes, pinocytotic vesicles, and lysosomes; on the other hand, the nonmembranous organelles listed as nucleoid, ribosomes, proteasomes, cilia, flagella, centrioles, and some components of the cytoplasm such asmMicrofilaments, microtubules, and intermediate filaments.
What are Membranous Organelles?
The organelles which consist of a plasma membrane all around them are known as membranous organelles. Some organelles like endoplasmic reticulum, Golgi apparatus, nucleus, mitochondria, lysosomes, and plastids are considered as membranous organelles.
The membranous organelles are said to be fluid-filled and are generally separated from the contents of the cytoplasm through the defined membrane. The organelle ‘Endoplasmic Reticulum’ is referred to as a double membrane-bounded structure, which considered to be involved in the transferring of substances from one part of the organelle to the other part of the cell.
Endoplasmic Reticulum has two types, depending on the presence of the ribosomes: SER and RER. SER does not contain ribosomes on its surface, while RER contains ribosomes on its surface and involve in the production of proteins. ‘Golgi Apparatus’ is another known single membranous organelle that consists of a secretory function in the cell.
‘Lysosomes’ are also membranous organelles that formed from the Golgi apparatus. Lysosomes consist of digestive enzymes. ‘Mitochondria’ is known as the powerhouse of the cell, which is also a membrane-bounded organelle involved in cellular respiration. Mitochondria is present in different shapes such as spherical, rod-shaped, or oval.
‘Chloroplasts’ are the double membranous organelles that consist of both smooth membranes. It also consists of a matrix called stroma, the complex layers of disk-like structures, which are known as thylakoids. The green color of the leaves is because of the presence of the chloroplast, which consists of a green chlorophyll pigment inside the leaf.
What are Nonmembranous Organelles?
The organelles which do not consist of any definite boundary are known as nonmembranous organelles. Furthermore, these nonmembranous organelles do not consist of any fluid-filled cavities. The organelles which are present in prokaryotes are said to be nonmembranous.
Organelles like centrioles, nucleoid, ribosomes, flagella, cilia, and parts of the cytoplasm such as microfilaments, intermediate filaments, and microtubules are nonmembranous organelles. ‘Nucleoid’ is a nonmembranous organelle and is considered a region of cytoplasm where the genetic material of prokaryotes is present.
‘Ribosomes’ are also nonmembranous organelles and are responsible for the synthesis of proteins from mRNA (messenger RNA). Ribosomes are made of RNA with bound proteins. Two types of ribosomes are the 70S and 80S. Prokaryotes contain 70S ribosomes, and 80S is present in eukaryotes.
The ‘Cytoskeleton’ is also known as nonmembranous organelle and which functions in providing the support and shape to the cell. It has two types of nonmembranous components; Microfilaments and Microtubules. Microfilaments are known to be unbranched hard rod-like structures, which are protein fibers and made up of a tubulin protein, Microtubules, which are hollow and have a cylindrical structure. They are tubes of protein that made up of tubulin protein.
‘Centrioles’ are considered as nonmembranous organelles which are made up of triplets of microtubules, usually arranged around a cavity, but there is no central microtubule. Therefore, they show the microtubules in an arrangement of 9+0.
