What are Mitochondria?
Mitochondria are part of the structure of a cell responsible for providing the energy for cellular respiration to occur, synthesizing adenosine triphosphate (ATP) molecules to obtain the chemical fuel that each cell needs to function properly. Mitochondria are organelles that act as a powerhouse, taking up amino acids, glucose, and fatty acids to obtain large amounts of ATP, in eukaryotic cells with aerobic metabolism.
Its discovery occurred in 1880 when Kölliker observed granules in muscle cells, however it was in 1889 that the scientist Benda assigned the term mitochondria to refer to these organelles.
Among the characteristics of the mitochondria is its size, which is quite large, it can even exceed the cell nucleus in proportion. Its shape is generally elongated, although it can be varied. The number of mitochondria present in the same cell depends on the type and function that the cell fulfills in the organism.
Its structure is covered by two membranes, the outer membrane that contains proteins, which gives it the quality of being porous, thus allowing the entry of large molecules; and the inner membrane that has a greater amount of proteins, although with little porosity, making it more selective, it also contains enzymes and systems that favor the transport of substances between the membranes. Inside it are the mitochondrial cristae , which are folds that function as catalysts and transport materials into the interior of the organelle; the intermembrane space , rich in protons and where the enzyme complex for cellular respiration originates and the matrix, or also known as mitosol, which is where the oxidation of metabolites occurs and the obtaining of ATP. In addition, the mitochondrial matrix is responsible for carrying out processes that are essential for life, such as the Krebs cycle, beta oxidation of fatty acids, oxidation of amino acids, synthesis of urea and heme groups.
What are Chloroplasts?
They are organelles typical of algae and plants, which fulfill an essential function in the eukaryotic cells of these organisms, such as photosynthesis. This metabolic process manages to synthesize organic substances using sunlight as an energy source.
Likewise, the chloroplast is related to the production of metabolic energy (ATP), as well as the synthesis of amino acids, fatty acids, vitamins, lipids and nitrite reduction. On the other hand, they comply with the production of substances that allow the cells of the organism of the plant kingdom to defend themselves against pathogens.
Chloroplasts have among their main characteristics that they have their own genome, that is, they contain their genetic material inside. Its shape is oval surrounded by membranes, with a dynamic structure and containing its own genetic material. These organelles are usually located in plant leaves, and each cell contains 10 to 100 chloroplasts.
The structure of chloroplasts has two membranes: the outer membrane is responsible for generating ATP and its surface is porous to allow the passage of molecules into the organelle; the internal membrane , for its part, does not allow the free transit of substances except through carriers anchored to it. Within the chloroplast are the thylakoids , which are shaped like flat discs or sacs with membranous bodies that are grouped together to transport electrons and photosynthetic pigments. There is also the stroma, which is a gelatinous liquid inside the chloroplast and that surrounds the thylakoids with a large number of proteins, enzymes and chloroplast ribosomes, which facilitates the synthesis of its own proteins.
Among the functions of the chloroplast is photosynthesis, which in its light phase synthesizes ATP in the stroma thanks to the transfer of electrons that provides the necessary energy to the pigment that forms in the thylakoid membranes, called chlorophyll. But in its dark phase, the stroma reacts by fixing carbon dioxide, in what is known as the Calvin cycle. On the other hand, there are the metabolic processes of plants in which various chemical reactions occur from this organelle.
Differences between Mitochondria and Chloroplasts
- Mitochondria are found in the cells of animal organisms and some plants, while chloroplasts are only present in plants and algae.
- Chloroplasts are responsible for the photosynthesis process of the plant organism, while mitochondria function as the cell’s energy source.
- The mitochondria in its structure has crests to transport substances into the interior of the organelle; Chloroplasts, on the other hand, have a smooth inner membrane.
- Within the chloroplast, the Calvin cycle occurs, which describes the process of photosynthesis. Inside the mitochondria, the Krebs cycle originates, which explains cellular respiration.
- The shape of the mitochondria is elongated and that of the chloroplast is oval and larger than the mitochondria.