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MtDNA
Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the DNA contained in a eukaryotic cell; most of the DNA is in the cell nucleus, and, in plants and algae, the DNA also is found in plastids, such as chloroplasts. Mitochondrial DNA is responsible for coding of 13 essential subunits of the complex oxidative phosphorylation (OXPHOS) system which has a role in cellular energy conversion. Human mitochondrial DNA was the first significant part of the human genome to be sequenced. This sequencing revealed that human mtDNA has 16,569 base pairs and encodes 13 proteins. As in other vertebrates, the human mitochondrial genetic code differs slightly from nuclear DNA. Since animal mtDNA evolves faster than nuclear genetic markers, it represents a mainstay of phylogenetics and evolutionary biology. It also permits tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Mitochondrial DNA
Human mitochondrial genetics is the study of the genetics of human mitochondrial DNA (the DNA contained in human mitochondria). The human mitochondrial genome is the entirety of hereditary information contained in human mitochondria. Mitochondria are small structures in cells that generate energy for the cell to use, and are hence referred to as the "powerhouses" of the cell. Mitochondrial DNA (mtDNA) is not transmitted through nuclear DNA (nDNA). In humans, as in most multicellular organisms, mitochondrial DNA is inherited only from the mother's ovum. There are theories, however, that paternal mtDNA transmission in humans can occur under certain circumstances. Mitochondrial inheritance is therefore non-Mendelian, as Mendelian inheritance presumes that half the genetic material of a fertilized egg (zygote) derives from each parent. This allowed the creation of mitochondrial DNA haplogroups to study population genetics. Eighty percent of mitochondrial DNA codes for mitoc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrial DNA Lg
A mitochondrion () is an organelle found in the cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'', meaning a thread-like granule, was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase popularized by Philip Siekevitz in a 1957 ''Scientific American'' article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). The multicellular animal '' Henneguya salminicola'' is known to have retained mitochondrion-related organelles despite a complete loss of their mitochondrial genome. A large number of unicellular organisms, such as microsporidia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrion
A mitochondrion () is an organelle found in the cell (biology), cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'', meaning a thread-like granule, was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase popularized by Philip Siekevitz in a 1957 ''Scientific American'' article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). The multicellular animal ''Henneguya zschokkei, Henneguya salminicola'' is known to have retained mitochondrion-related organelles despite a complete loss of their mitochondrial genome. A large number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrial DNA 3D
A mitochondrion () is an organelle found in the cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'', meaning a thread-like granule, was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase popularized by Philip Siekevitz in a 1957 ''Scientific American'' article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). The multicellular animal '' Henneguya salminicola'' is known to have retained mitochondrion-related organelles despite a complete loss of their mitochondrial genome. A large number of unicellular organisms, such as microsporidia, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Gene
A nuclear gene is a gene whose DNA sequence is located within the cell nucleus of a eukaryotic organism. These genes are distinguished from extranuclear genes, such as those found in the genomes of mitochondria and chloroplasts, which reside outside the nucleus in their own organellar DNA. Nuclear genes encode the majority of proteins and functional RNAs required for cellular processes, including development, metabolism, and regulation. Unlike the small, circular genomes of mitochondria and chloroplasts, nuclear genes are organized into linear chromosomes and are typically inherited in a Mendelian fashion, following the laws of segregation and independent assortment. In contrast, extranuclear genes often exhibit non-Mendelian inheritance, such as maternal inheritance in mitochondrial DNA. While the vast majority of eukaryotic genes are nuclear, exceptions exist in certain protists and algae, where some genes have migrated from organelles to the nucleus over evolutionary time th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Genome
The human genome is a complete set of nucleic acid sequences for humans, encoded as the DNA within each of the 23 distinct chromosomes in the cell nucleus. A small DNA molecule is found within individual Mitochondrial DNA, mitochondria. These are usually treated separately as the nuclear genome and the Human mitochondrial genetics, mitochondrial genome. Human genomes include both protein-coding DNA sequences and various types of non-coding DNA, DNA that does not encode proteins. The latter is a diverse category that includes DNA coding for non-translated RNA, such as that for ribosomal RNA, transfer RNA, ribozymes, small nuclear RNAs, and several types of RNA#Regulatory RNA, regulatory RNAs. It also includes Promoter (biology), promoters and their associated Cis-regulatory element, gene-regulatory elements, DNA playing structural and replicatory roles, such as Scaffold/matrix attachment region, scaffolding regions, telomeres, centromeres, and Origin of replication, origins of repl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroplast
A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which capture the Radiant energy, energy from sunlight and convert it to chemical energy and release oxygen. The chemical energy created is then used to make sugar and other organic molecules from carbon dioxide in a process called the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in some unicellular algae, up to 100 in plants like ''Arabidopsis'' and wheat. Chloroplasts are highly dynamic—they circulate and are moved around within cells. Their behavior is strongly influenced by environmental factors like light color and intensity. Chloroplasts cannot be made anew by the plant cell and must ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endosymbiotic Theory
Symbiogenesis (endosymbiotic theory, or serial endosymbiotic theory) is the leading evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms. The theory holds that mitochondria, plastids such as chloroplasts, and possibly other organelles of eukaryotic cells are descended from formerly free-living prokaryotes (more closely related to the Bacteria than to the Archaea) taken one inside the other in endosymbiosis. Mitochondria appear to be phylogenetically related to Rickettsiales bacteria, while chloroplasts are thought to be related to cyanobacteria. The idea that chloroplasts were originally independent organisms that merged into a symbiotic relationship with other one-celled organisms dates back to the 19th century, when it was espoused by researchers such as Andreas Schimper. The endosymbiotic theory was articulated in 1905 and 1910 by the Russian botanist Konstantin Mereschkowski, and advanced and substantiated with microbiological evidence by Lyn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Code
Genetic code is a set of rules used by living cell (biology), cells to Translation (biology), translate information encoded within genetic material (DNA or RNA sequences of nucleotide triplets or codons) into proteins. Translation is accomplished by the ribosome, which links proteinogenic amino acids in an order specified by messenger RNA (mRNA), using transfer RNA (tRNA) molecules to carry amino acids and to read the mRNA three nucleotides at a time. The genetic code is highly similar among all organisms and can be expressed in a simple table with 64 entries. The codons specify which amino acid will be added next during protein biosynthesis. With some exceptions, a three-nucleotide codon in a nucleic acid sequence specifies a single amino acid. The vast majority of genes are encoded with a single scheme (see the Codon tables, RNA codon table). That scheme is often called the canonical or standard genetic code, or simply ''the'' genetic code, though #Variations, variant codes (suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastid
A plastid is a membrane-bound organelle found in the Cell (biology), cells of plants, algae, and some other eukaryotic organisms. Plastids are considered to be intracellular endosymbiotic cyanobacteria. Examples of plastids include chloroplasts (used for photosynthesis); chromoplasts (used for synthesis and storage of pigments); leucoplasts (non-pigmented plastids, some of which can cellular differentiation, differentiate); and apicoplasts (non-photosynthetic plastids of apicomplexa derived from secondary endosymbiosis). A permanent primary endosymbiosis event occurred about 1.5 billion years ago in the Archaeplastida cladeEmbryophyte, land plants, red algae, green algae and glaucophytesprobably with a cyanobiont, a symbiotic cyanobacteria related to the genus ''Gloeomargarita lithophora, Gloeomargarita''. Another primary endosymbiosis event occurred later, between 140 and 90 million years ago, in the photosynthetic plastids ''Paulinella'' amoeboids of the cyanobacteria genera '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biogeography
Biogeography is the study of the species distribution, distribution of species and ecosystems in geography, geographic space and through evolutionary history of life, geological time. Organisms and biological community (ecology), communities often vary in a regular fashion along geographic gradients of latitude, elevation, allopatric speciation, isolation and habitat species-area curve, area. Phytogeography is the branch of biogeography that studies the distribution of plants. Zoogeography is the branch that studies distribution of animals. Mycogeography is the branch that studies distribution of fungi, such as mushrooms. Knowledge of spatial variation in the numbers and types of organisms is as vital to us today as it was to our early human ancestors, as we adapt to heterogeneous but geographically predictable Natural environment, environments. Biogeography is an integrative field of inquiry that unites concepts and information from ecology, evolutionary biology, taxonomy (bio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homogeneity And Heterogeneity
Homogeneity and heterogeneity are concepts relating to the uniformity of a substance, process or image. A homogeneous feature is uniform in composition or character (i.e., color, shape, size, weight, height, distribution, texture, language, income, disease, temperature, radioactivity, architectural design, etc.); one that is heterogeneous is distinctly nonuniform in at least one of these qualities. Etymology and spelling The words ''homogeneous'' and ''heterogeneous'' come from Medieval Latin ''homogeneus'' and ''heterogeneus'', from Ancient Greek ὁμογενής (''homogenēs'') and ἑτερογενής (''heterogenēs''), from ὁμός (''homos'', "same") and ἕτερος (''heteros'', "other, another, different") respectively, followed by γένος (''genos'', "kind"); -ous is an adjectival suffix. Alternate spellings omitting the last ''-e-'' (and the associated pronunciations) are common, but mistaken: ''homogenous'' is strictly a biological/pathological term whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
