Mitochondria vs Chloroplast
Both mitochondria and chloroplast are two large organelles found in eukaryotic cells. They are known as the cellular generators of eukaryotic cells. These two organelles and symbiotic bacterial cells share some structural features such as the ability of self-replicating, and the presence of circular DNA and similar ribosomes. Because of such similarities, it is believed that the mitochondria and chloroplast have evolved from small symbiotic bacteria. This phenomenon is further described in the theory called ‘endosymbiosis’. Additionally both organelles are involved in energy metabolisms in cells, and hence they share functional similarities, as well. However, the physiologies of mitochondria and chloroplasts have some significant differences.
What are Mitochondria?
Mitochondria are large, membrane bounded, tube-shaped organelles found in all types of eukaryotic cells. The size of mitochondria is similar to that of bacterial cell. Mitochondria have two membranes; a smooth outer membrane, and an inner folded membrane. Inner membrane has numerous layers called cristae, which separate the mitochondrion into two sections; a matrix, and an intermembrane space. The matrix is the section that lies inside the inner membrane, and it contains mitochondrial DNA and enzymes, whereas the intermembrane space is the section that lies between the inner and outer membrane. The proteins responsible for carrying out oxidative metabolism are found on or embedded within the inner membrane.
Mitochondrial DNA contains certain genes that produce essential proteins, which are used in oxidative metabolism. Thus, mitochondria have the ability to produce proteins for their unique function unlike most of the other organelles in the cells. However, mitochondria cannot replicate by themselves without nuclear participation. This is because, some nuclear genes are essential in order to produce components needed to complete mitochondrial replication. Thus, it is impossible to grow mitochondria in a cell-free culture. The main function of mitochondria is to metabolize sugar to generate ATP.
What is a Chloroplast?
Chloroplasts are membrane bounded large organelles found only in eukaryotic cells that carry out photosynthesis, such as plant cells and green algae. As the name implies, chloroplast contains photosynthetic pigment called chlorophyll. Because of the presence of this pigment, chloroplasts can utilize light to synthesize ATP and sugars. Thus, the organisms with chloroplasts can produce their own food.
Chloroplasts have two membranes, similar to mitochondria. In addition to these membranes, they have closed compartments called grana. Grana are found inside the inner membrane, and each granum is made up of few to several dish shaped structures called thylakoids. The chlorophyll is found on these thylakoids. Stroma is the fluid matrix that surrounds the thylakoids and contains enzymes used in photosynthesis.
What is the difference between Mitochondria and Chloroplast?
• Chloroplast is larger and more complex than mitochondrion.
• Chloroplasts use light to produce ATP and sugars, whereas mitochondria use sugars to produce ATP.
• Chloroplasts found only in photosynthetic eukaryotic organisms, such as plants and green algae, whereas mitochondria found in every eukaryotic organism.
• Mitochondria have matrix, and chloroplasts have stroma.
• Unlike the mitochondria, chloroplasts contain a pigment called chlorophyll and thylakoid disks.
• Unlike the inner membrane of the chloroplasts, the inner membrane of the mitochondria is folded to form cristae.