Some of the ATP produced by mitochondria is generated directly during glycolysis and the Kreb’s Cycle, which is also called the Tri-Carboxylic Acid (TCA) Cycle. More ATP is generated from a chemical called NADPH. This is the starting point of the electron transfer chain (also called Hydrogen transfer). The final Hydrogen acceptor is Oxygen. NADPH is produced during the Kreb’s Cycle. One molecule of NADPH can be used to generate three molecules of ATP.
RNA is a nucleic acid like DNA, but with 4 differences:
* RNA has the sugar ribose instead of deoxyribose
* RNA has the base uracil instead of thymine
* RNA is usually single stranded
* RNA is usually shorter than DNA
Messenger RNA (mRNA)
mRNA carries the "message" that codes for a particular protein from
the nucleus (where the DNA master copy is) to the cytoplasm (where
proteins are synthesised).
Both photosynthesis and tissue respiration require a large number of enzymes. Therefore both chloroplasts and mitochondria contain DNA and ribosomes.
An intermediate in this process, called mRNA (messenger ribonucleic acid), is made from the DNA template and serves as a link to molecular machines called ribosomes.
Energy is also needed for growth and repair. When cells make protein from amino-acids, they require energy from ATP. It is also necessary to use ATP to link glucose molecules together to form starch or glycogen.
Then, on the inside of the cell, ATP (Adenosine TriPhosphate) binds toanother site on the carrier and phosphorylates (adds one of its phospategroups, or -PO, to) one of theamino acids that is part of the carrier molecule.
DNA is a term used for deoxyribonucleic acid and it is the genetic material of all organisms, it is the molecule of life and it determines all of our physical characteristics.
ATP is very much less stable than either glucose or glycogen, so it cannot be used to store energy or to transport energy. Cells make ATP when and where they need it. Muscle cells need a lot of ATP so they have lots of mitochondria. Muscle cells convert chemical energy (in ATP) into kinetic energy: striated muscles contain two important proteins, actin and myosin; these can combine to form actinomyosin. Strands of actinomyosin shorten when ATP is put on them. So every time a muscle contracts, chemical energy is converted into kinetic energy.
Cells need energy for other processes such as the synthesis of proteins from amino-acids and the replication of DNA. This energy usually comes from the breakdown of glucose; though fats and proteins can also be used a sources of energy. Glucose is a stable chemical: it does not just breakdown releasing energy. Since glucose can pass through cell membranes it is used to transport energy from one part of your body to another in your blood.
The conventional teaching in biology and medicine is that mitochondria function only as “energy factories” for the cell. This over-simplification is a mistake which has slowed our progress toward understanding the biology underlying mitochondrial disease. It takes about 3000 genes to make a mitochondrion. Mitochondrial DNA encodes just 37 of these genes; the remaining genes are encoded in the cell nucleus and the resultant proteins are transported to the mitochondria. Only about 3% of the genes necessary to make a mitochondrion (100 of the 3000) are allocated for making ATP. More than 95% (2900 of 3000) are involved with other functions tied to the specialized duties of the differentiated cell in which it resides. These duties change as we develop from embryo to adult, and our tissues grow, mature, and adapt to the postnatal environment. These other, non-ATP-related functions are intimately involved with most of the major metabolic pathways used by a cell to build, break down, and recycle its molecular building blocks. Cells cannot even make the RNA and DNA they need to grow and function without mitochondria. The building blocks of RNA and DNA are purines and pyrimidines. Mitochondria contain the rate-limiting enzymes for pyrimidine biosynthesis (dihydroorotate dehydrogenase) and heme synthesis (d-amino levulinic acid synthetase) required to make hemoglobin. In the liver, mitochondria are specialized to detoxify ammonia in the urea cycle. Mitochondria are also required for cholesterol metabolism, for estrogen and testosterone synthesis, for neurotransmitter metabolism, and for free radical production and detoxification. They do all this in addition to breaking down (oxidizing) the fat, protein, and carbohydrates we eat and drink.
Respiration is a series of reactions in which 6-carbon glucose is oxidised to form . The energy released due to the oxidation of is used to synthesize ATP from adenosine diphosphate or ADP and inorganic phosphate or Pi.
Because mitochondria perform so many different functions in different tissues, there are literally hundreds of different mitochondrial diseases. Each disorder produces a spectrum of abnormalities that can be confusing to both patients and physicians in early stages of diagnosis. Because of the complex interplay between the hundreds of genes and cells that must cooperate to keep our metabolic machinery running smoothly, it is a hallmark of mitochondrial diseases that identical mtDNA mutations may not produce identical diseases. Genocopies are diseases that are caused by the same mutation but which may not look the same clinically.