Mitochondria and chloroplasts (article) | Khan Academy
Mitochondria make ATP, the energy molecules of cells, from glucose. adopted most multicelled animals billions of years ago for the symbiotic relationship. Having said that, ribosomes are specialized for completely different function that is. Structure and function of mitochondria and chloroplasts. Why would these organelles need DNA and ribosomes, when there is DNA in the nucleus and scientists think host cells and bacteria formed endosymbiotic relationships long ago. A ribosome is a cell organelle that makes proteins from messenger RNA Mitochondria and chloroplasts have their own ribosomes, which.
Inner Membrane The inner membrane is more complex in structure than the outer membrane as it contains the complexes of the electron transport chain and the ATP synthase complex.
It is permeable only to oxygen, carbon dioxide and water. The inner membrane is made up of a large number of proteins that play an important role in producing ATP, and also helps in regulating transfer of metabolites across the membrane.
The inner membrane has infoldings called the cristae that increase the surface area for the complexes and proteins that aid in the production of ATP, the energy rich molecules. Besides these, it has oxygen, carbon dioxide and other recyclable intermediates. Although most of the genetic material of a cell is contained within the nucleus, the mitochondria have their own DNA. They have their own machinery for protein synthesis and reproduce by the process of fission like bacteria do.
Due to their independence from the nuclear DNA and similarities with bacteria, it is believed that mitochondria have originated from bacteria by endosymbiosis. Functions Functions of mitochondria vary according to the cell type in which they are present.The Cell-Ribosomes
The most important function of the mitochondria is to produce energy. The food that we eat is broken into simpler molecules like carbohydrates, fats, etc. These are sent to the mitochondria where they are further processed to produce charged molecules that combine with oxygen and produce ATP molecules. This entire process is known as oxidative phosphorylation. It is important to maintain proper concentration of calcium ions within the various compartments of the cell.
Structure and Function of the Mitochondrial Ribosome.
Mitochondria help the cells to achieve this goal by serving as storage tanks of calcium ions. They play an important role in the process of programmed cell death. Unwanted and excess cells are pruned away during the development of an organism. The process is known as apoptosis.
Abnormal cell death due to mitochondrial dysfunction can affect the function of the organ. Dysfunction Over 50 million people in the U. Dysfunction of mitochondria can affect the production of cell-specific products that are essential for proper cell functioning and energy production. This can eventually lead to cell death and failure of the organ system. It can even prove to be fatal in some cases.
Mitochondrial disease When the ability of the mitochondria to produce energy is reduced due to certain defects a genetic mutation in either the mitochondrial DNA or the nuclear DNAthe condition is described as 'mitochondrial disease'.
Reduced production of energy can lead to dysfunction of brain, vision problems, weak muscles, restricted movement of limbs, etc. The energy contained in these sugars is harvested through a process called cellular respiration, which happens in the mitochondria of both plant and animal cells.
Chloroplasts are disc-shaped organelles found in the cytosol of a cell. They have outer and inner membranes with an intermembrane space between them. Diagram of a chloroplast, showing the outer membrane, inner membrane, intermembrane space, stroma, and thylakoids arranged in stacks called grana. Thylakoid discs are hollow, and the space inside a disc is called the thylakoid space or lumen, while the fluid-filled space surrounding the thylakoids is called the stroma.
You can learn more about chloroplasts, chlorophyll, and photosynthesis in the photosynthesis topic section.
The Structure and Function of Ribosomes Explained
Mitochondria Mitochondria singular, mitochondrion are often called the powerhouses or energy factories of the cell. The process of making ATP using chemical energy from fuels such as sugars is called cellular respirationand many of its steps happen inside the mitochondria.
The mitochondria are suspended in the jelly-like cytosol of the cell. They are oval-shaped and have two membranes: Electron micrograph of a mitochondrion, showing matrix, cristae, outer membrane, and inner membrane. Modification of work by Matthew Britton; scale-bar data from Matt Russell.
The matrix contains mitochondrial DNA and ribosomes. We'll talk shortly about why mitochondria and chloroplasts have their own DNA and ribosomes. The multi-compartment structure of the mitochondrion may seem complicated to us. That's true, but it turns out to be very useful for cellular respirationallowing reactions to be kept separate and different concentrations of molecules to be maintained in different "rooms. Electrons from fuel molecules, such as the sugar glucose, are stripped off in reactions that take place in the cytosol and in the mitochondrial matrix.
These electrons are captured by special molecules called electron carriers and deposited into the electron transport chaina series of proteins embedded in the inner mitochondrial membrane. As protons flow back down their gradient and into the matrix, they pass through an enzyme called ATP synthase, which harnesses the flow of protons to generate ATP.
This process of generating ATP using the proton gradient generated by the electron transport chain is called oxidative phosphorylation.
The compartmentalization of the mitochondrion into matrix and intermembrane space is essential for oxidative phosphorylation, as it allows a proton gradient to be established. These electrons are captured by special molecules called electron carriers and deposited into the electron transport, a series of proteins embedded in the inner mitochondrial membrane. For instance, muscle cells typically have high energy needs and large numbers of mitochondria, while red blood cells, which are highly specialized for oxygen transport, have no mitochondria at all.
Both mitochondria and chloroplasts contain their own DNA and ribosomes. Strong evidence points to endosymbiosis as the answer to the puzzle. Symbiosis is a relationship in which organisms from two separate species live in a close, dependent relationship.
The first endosymbiotic event occurred: The ancestral eukaryote consumed aerobic bacteria that evolved into mitochondria. In a second endosymbiotic event, the early eukaryote consumed photosynthetic bacteria that evolved into chloroplasts. Bacteria also have DNA and ribosomes similar to those of mitochondria and chloroplasts. Through millions of years of evolution, the aerobic bacteria became mitochondria and the photosynthetic bacteria became chloroplasts.
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