The key difference between mitochondria and kinetoplast is that mitochondria are eukaryotic cell organelles that produce energy (ATP). Meanwhile, kinetoplast is a network of circular DNA present inside a large mitochondrion, specifically in protozoa of the class Kinetoplastea.
Eukaryotic cells have different types of cell organelles. These different organelles carry out different functions within the living cell. Of these, mitochondria are one of the membrane-bound organelles seen in a eukaryotic cell. They are the organelles that are responsible for energy (in the form of ATP) production in cells. Hence, they are considered as powerhouses of the cell. Mitochondria have their own genome, which is circular DNA inherited maternally. Kinetoplast is the network of circular DNA seen in the large mitochondrion of the organisms belonging to class Kinetoplastida. Therefore, kinetoplasts are seen only in this eukaryotic subdomain.
CONTENTS
1. Overview and Key Difference
2. What are Mitochondria
3. What is Kinetoplast
4. Similarities Between Mitochondria and Kinetoplast
5. Side by Side Comparison – Mitochondria vs Kinetoplast in Tabular Form
6. Summary
What are Mitochondria?
Mitochondria are double membrane-bound eukaryotic cell organelles. They are the powerhouses of eukaryotic cells. Cellular respiration takes place in the mitochondria. It is the process which produces the energy needed for all cellular processes. Among the three main processes of cellular respiration, two processes occur inside the mitochondria. Mitochondria are present in the cell cytoplasm. Moreover, they are rod-shaped organelles. Mitochondria have their own genomes inherited maternally. There are two phospholipid bilayers called outer membrane and inner membrane in mitochondria. The inner membrane is compartmentalized into cristae in order to increase the surface area for oxidative phosphorylation. Mitochondrial matrix is the space enclosed by the inner membrane.
Figure 01: Mitochondrion
The number of mitochondria found in a cell varies based on the organism, tissue and the cell types. Some cells, especially red blood cells, lack mitochondria while some cells like liver cells have more than 2000 mitochondria per cell. In addition to the production of ATP (cellular energy), mitochondria involve in other functions including cell signalling, cellular differentiation, cell growth, cell death, and generating heat.
What is Kinetoplast?
Kinetoplast is a network of circular DNA found in large mitochondria of the class Kinetoplastida of Excavata. Therefore, kinetoplast contains many copies of the mitochondrial genome. It is mainly a disk-shaped structure. Kinetoplast circular DNA exists in two forms: maxicircles and minicircles. Maxicircles are 20 and 40kb in size while minicircles are 0.5 and 1kb in size. Generally, there are several thousand minicircles while there are a few dozen maxicircles in a mitochondrion. Kinetoplast DNA is present in the mitochondrial matrix perpendicular to the axis of the flagellum.
Figure 02: Kinetoplast
There is a variation in kinetoplast between kinetoplastids based on the arrangement and location of their kDNA. And, this variation is helpful when determining the evolutionary relationship between the species of kinetoplastids.
What are the Similarities Between Mitochondria and Kinetoplast?
- Mitochondria and kinetoplasts are found only in eukaryotes.
- Kinetoplasts are circular DNA found in large mitochondria of Kinetoplastida unicellular organisms.
What is the Difference Between Mitochondria and Kinetoplast?
Mitochondria are eukaryotic, membrane-bound organelles present in the cytoplasm, while kinetoplast is a circular DNA found in mitochondria of Kinetoplastida organisms. So, this is the key difference between mitochondria and kinetoplast. Furthermore, while mitochondria are cell organelles, kinetoplast is DNA.
Moreover, another difference between mitochondria and kinetoplast is that mitochondria are rod-shaped, whereas kinetoplast is disk-shaped. Besides, mitochondria produce ATP for cellular processes via cellular respiration, whereas kinetoplast exists as mitochondria DNA in unicellular kinetoplastids.
Summary – Mitochondria vs Kinetoplast
Mitochondria are the powerhouses of eukaryotic cells. They are membrane-bound cell organelles present in the cytoplasm. Cellular respiration takes place in mitochondria. Moreover, there is a mitochondrial genome in each mitochondrion. Kinetoplast is the network of circular DNA present in the large mitochondrion of a special group called Kinetoplastida. Kinetoplast structure is mainly disk-shaped. So, this is the summary of the difference between mitochondria and kinetoplast.
Reference:
1. Rogers, Kara. “Mitochondrion.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 12 Sept. 2019, Available here.
2. “Kinetoplast.” Kinetoplast – an Overview | ScienceDirect Topics, Available here.
Image Courtesy:
1. “Animal mitochondrion diagram en (edit)” By Mariana Ruiz Villarreal LadyofHats (Public Domain) via Commons Wikimedia
2. “Kinetoplast Replication” By Aiox82 (CC BY-SA 3.0) via Commons Wikimedia