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Mitochondrial disease is a group of disorders caused by mitochondrial dysfunction. Mitochondria are the organelles that generate energy for the cell and are found in every cell of the human body except red blood cells. They convert the energy of food molecules into the ATP that powers most cell functions.
For eukaryotes, oxidative reactions are a major source of DNA damage (see DNA damage (naturally occurring) and Sedelnikova et al. [23]). In humans, about 10,000 oxidative DNA damages occur per cell per day. [24] In the rat, which has a higher metabolic rate than humans, about 100,000 oxidative DNA damages occur per cell per day.
In humans, as in most eukaryotes, the 18S rRNA is a component of 40S ribosomal subunit, and the 60S large subunit contains three rRNA species (the 5S, 5.8S and 28S in mammals, 25S in plants). 60S rRNA acts as a ribozyme, catalyzing peptide bond formation, while 40S monitors the complementarity between tRNA anticodon and mRNA. [citation needed]
Anencephaly is one such disease, part of an emerging class of diseases called ciliopathies. The underlying cause may be a dysfunctional molecular mechanism in the primary cilia structures of the cell , organelles present in many cellular types throughout the human body.
At birth, all copies of mitochondrial DNA are thought to be identical in most humans. [2] Microheteroplasmy is mutations of up to about 2−5% of mitochondrial genomes, and is present in most adults. This refers to hundreds of independent mutations in one organism, with each mutation found in about 1–2% of all mitochondrial genomes. [ 3 ]
Overview of signal transduction pathways involved in apoptosis. Cell death is the event of a biological cell ceasing to carry out its functions. This may be the result of the natural process of old cells dying and being replaced by new ones, as in programmed cell death, or may result from factors such as diseases, localized injury, or the death of the organism of which the cells are part.
Peroxisomal disorders represent a class of medical conditions caused by defects in peroxisome functions. [1] This may be due to defects in single enzymes [2] important for peroxisome function or in peroxins, proteins encoded by PEX genes that are critical for normal peroxisome assembly and biogenesis.
Tay–Sachs disease was the first of these disorders to be described, in 1881, followed by Gaucher disease in 1882. In the late 1950s and early 1960s, de Duve and colleagues, using cell fractionation techniques, cytological studies, and biochemical analyses, identified and characterized the lysosome as a cellular organelle responsible for ...