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About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium. All 11 are necessary for life. The remaining elements are trace elements, of which more than a dozen are ...
Most biomolecules are organic compounds, and just four elements — oxygen, carbon, hydrogen, and nitrogen —make up 96% of the human body 's mass. But many other elements, such as the various biometals, are also present in small amounts. The uniformity of both specific types of molecules (the biomolecules) and of certain metabolic pathways ...
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body. MRI does not involve X-rays or the use of ionizing ...
Cellular respiration. Typical eukaryotic cell. Cellular respiration is the process by which biological fuels are oxidized in the presence of an inorganic electron acceptor, such as oxygen, to drive the bulk production of adenosine triphosphate (ATP), which contains energy. Cellular respiration may be described as a set of metabolic reactions ...
Biohydrogen is H 2 that is produced biologically. [1] Interest is high in this technology because H 2 is a clean fuel and can be readily produced from certain kinds of biomass, [2] including biological waste. [3] Furthermore some photosynthetic microorganisms are capable to produce H 2 directly from water splitting using light as energy source ...
Biological roles of the elements. A large fraction of the chemical elements that occur naturally on the Earth's surface are essential to the structure and metabolism of living things. Four of these elements (hydrogen, carbon, nitrogen, and oxygen) are essential to every living thing and collectively make up 99% of the mass of protoplasm. [ 1 ]
For acidosis referring to acidity of the urine, see Renal tubular acidosis. Acidosis is a biological process producing hydrogen ions and increasing their concentration in blood or body fluids. pH is the negative log of hydrogen ion concentration and so it is decreased by a process of acidosis.
A hydrogenase is an enzyme that catalyses the reversible oxidation of molecular hydrogen (H 2), as shown below: H 2 + A ox → 2H + + A red. (1) 2H + + D red → H 2 + D ox. (2) Hydrogen uptake (1) is coupled to the reduction of electron acceptors such as oxygen, nitrate, sulfate, carbon dioxide (CO 2), and fumarate.