What is the function of the mitochondria in a plant? Several things have been studied regarding the role of the mitochondria in a plant, including regulation of their biogenesis by microRNAs.
Chloroplasts
Chloroplasts are plant organelles that capture energy from sunlight and convert it into sugars. They play several crucial roles in plant cell life, including cellular respiration and photosynthesis. The chloroplasts are most commonly found in the leaves of plants. However, some plants are not known to have chloroplasts. One such example is rafflesia. It does not have visible leaves or roots, but it is still dependent on a host for sugar.
Although the mitochondria of animals and plants are similar, the chloroplast is more complex. A large number of genes are encoded in the chloroplast genome, which is circular. These genes are used to encode proteins for ATP synthesis, gene expression, and photosynthesis. Most of the proteins in the chloroplast membrane are directed by free ribosomes in the cytoplasm. Unlike the mitochondria, however, the chloroplast uses a double membrane, which divides it into compartments. Each compartment has its own separate environment for certain reactions.
Chloroplasts are also made up of a semi-fluid material called stroma, which contains chloroplast DNA, enzymes, and starch granules. These enzymes and granules are responsible for the conversion of carbon dioxide to carbohydrates during photosynthesis. There are also dissolved enzymes and special ribosomes in the stroma.
In addition to the stroma, the chloroplast has an outer membrane, which is impermeable to ions and metabolites. This membrane is a type of delimiting membrane, which is similar to the membranes in eukaryotic cells. Within the stroma, there are three types of thylakoid sacks, which are connected by stromal lamellae.
Chloroplasts have a large number of tRNAs, which are the protein molecules that translate codons in the universal genetic code. Almost all of the chloroplast proteins are synthesised using cytosolic ribosomes. Moreover, they are imported into the chloroplast as polypeptide chains. Once inside the chloroplast, the proteins must be sorted for proper location. This process is referred to as protein sorting.
Another difference between the mitochondria and the chloroplast is that the stroma is filled with copies of the chloroplast genome. Since the chloroplast genome is copied, there are many copies of the same gene. Therefore, it is very important for the stroma to have a chromosomal duplicate of the chloroplast genome.
Another striking feature of the mitochondria is its inner membrane. Similar to the double membrane of the chloroplast, this membrane consists of an outer layer and an inner layer. However, the outer layer is more permeable than the inner layer. Both layers contain stroma, which fills the intermembrane space. Also, the inner membrane is made of porins, which help to separate the different components of the stroma.
Mitochondria and the chloroplast are important for the generation of ATP, but they have other functions in plant cells. Among them are breaking down fuel molecules, capturing energy from the cytoplasm, and regulating ATP synthesis. Without these organelles, the plant would not be able to survive.
Regulation of mitochondrial biogenesis by microRNAs
Mitochondrial biogenesis is a critical aspect of normal physiological function of the heart. The heart requires a large quantity of high-quality mitochondria in cardiomyocytes to meet the demand for cellular energy. Defects in mitochondrial biogenesis can lead to severe energy deficiency, increased reactive oxygen species and neuronal death. However, it remains unclear how miRNAs regulate these processes. Understanding crosstalk between miRNAs and mitochondria is essential for the prevention and treatment of cardiac diseases.
MiRNAs target multiple morphological, signaling and metabolic pathways that are important for normal mitochondrial function. Although a number of genes have been identified that are associated with mitochondrial biogenesis, there are still a lot of questions about the regulation of mitochondrial function by miRNAs. One miRNA that plays a major role in this process is Hsa-miR-155-5p. TFAM is a key regulator of mitochondrial biogenesis, and hsa-miR-155-5p directly interacts with it in trisomic cells. In order to study this effect, we used a transgenic mouse model of TFAM overexpression.
The expression of TFAM was reduced in DS fibroblasts and non-DS fibroblasts, which were treated with hsa-miR-155-5p. These results suggest that hsa-miR-155-5p negatively regulates the expression of TFAM and inhibits mitochondrial biogenesis. A more comprehensive study needs to be carried out to understand the mechanism of TFAM regulation by miRNAs.
Several aspects of regulation of mitochondrial metabolism have been discovered in the past few years. In particular, attention has been focused on pathways related to mitochondrial fusion and fission. Other novel aspects include cellular effects on mitochondrial biogenesis and dynamics. Our understanding of these processes is essential for the development of effective therapeutics for cardiac disease.
MicroRNAs are a class of single-stranded, 22-nt long noncoding RNAs that target a variety of gene functions, including mitochondrial biogenesis. They also interact with other transcription factors involved in regulating mitochondrial functions. Currently, several important mitochondrial-encoded miRNAs are known, including hsa-miR-155-5p, hsa-miR-494-3p, hsa-miR-200a, hsa-miR-181a, hsa-miR-181b and hsa-miR-389. Several studies have indicated that microRNAs regulate the expression of key mitochondrial proteins, including mitophagy, apoptosis, mitochondrial calcium, mtDNA copy number, mitochondrial fission, mtROS, ATP enzymatic activity and mitochondrial DNA. Nevertheless, little research has been done on direct targeting of the mitochondrial functional proteins.
Studies on the role of miRNAs in cardiac hypertrophy have been limited. However, they have been implicated in a number of other cardiovascular diseases. Therefore, the study of the role of miRNAs in this disease may help in the identification of potential biomarkers for this disorder.
Cardiovascular diseases are the most common causes of morbidity and mortality worldwide. Heart failure, myocarditis and diabetic cardiomyopathy are some of the most common forms of CVD. This article reviews the potential role of miRNAs in these diseases, as well as their theoretical basis. We conclude that further studies on the mechanisms of miRNAs in these diseases are needed to expand our knowledge of the biological role of miRNAs in cardiac diseases.
Function of mitochondria in a plant cell
Plant mitochondria function in many important cellular processes that help sustain photosynthesis. They also perform other functions for the cell. These include synthesis of vitamins, nucleotides, lipids, and amino acids. In addition to this, mitochondria are a major source of energy for the cell. The function of plant mitochondria is rapidly being investigated. However, more detailed insights into the mitochondrial structure, assembly, and signalling are needed to maximize respiration and minimise respiratory losses.
Plant mitochondria are membrane-bound organelles that produce energy for the cell through aerobic respiration. This process generates heat and CO2 for the plant. During the aerobic phase, the mitochondrial electron transport chain (ETC) couples oxidation of NAD(P)H and FADH2 to reduction of O2 and synthesis of ATP. It also plays a key role in maintaining the mitochondrial redox environment and in response to cellular stresses.
Plant mitochondria are complex and flexible. They have an inner membrane that is compartmentalized and a permeable outer membrane. A variety of folds in the inner membrane increase the surface area of the mitochondrial matrix, increasing the amount of ATP that can be produced. There are special channels that allow large molecules to diffuse through the outer membrane. Other channels facilitate the release of respiratory products to the rest of the cell. Various types of protein transporters and carrier proteins are involved in the transportation of proteins from the cytosol into the mitochondrion.
Plant mitochondria carry out several cellular processes, including synthesis of ATP, amino acids, lipids, nucleotides, and ribosomal proteins. Most of these proteins are synthesized from the nuclear genome. Some mitochondria can produce hundreds of different proteins. As with other cells, the composition of the plant mitochondrial proteome is variable and may vary from species to species and from one tissue type to another.
Detailed information on mitochondrial function is essential for understanding plant development and growth. Understanding the role of mitochondria in response to stress and abiotic conditions is also crucial. Studies of mitochondria have revealed that abiotic stress, such as oxidative stress, can induce a series of changes in the plant mitochondrial proteome. Oxidative stress can occur due to the accumulation of ROS, the production of HNE, and lipid peroxidation. Stress-induced alterations in the plant mitochondrial proteome can lead to developmental defects, cell death, and disease. Hence, it is vital to understand the plant mitochondrial proteome to optimize the protection of plants in harsh environments.
Mitochondria are thought to have originated as bacteria that were absorbed by a more complex organism. Some scientists believe that the mitochondria were first incorporated into a larger cell that was able to produce a sufficient quantity of chemical energy. Others propose that mitochondria may have evolved as part of a bacterial genome that was later absorbed by a more complex cell. Regardless of the origin of the organelles, their functions are regulated by genetic control.