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The first direct elections for native Kenyans to the Legislative Council took place in 1957. Despite British hopes of handing power to "moderate" local rivals, it was the Kenya African National Union (KANU) of Jomo Kenyatta that formed a government. The Colony of Kenya and the Protectorate of Kenya each came to an end ... |
The election held in 1988 saw the advent of the mlolongo (queuing) system, where voters were supposed to line up behind their favoured candidates instead of a secret ballot. This was seen as the climax of a very undemocratic regime and it led to widespread agitation for constitutional reform. Several contentious clause... |
Kenya is a presidential representative democratic republic. The President is both the head of state and head of government, and of a multi-party system. Executive power is exercised by the government. Legislative power is vested in both the government and the National Assembly and the Senate. The Judiciary is independe... |
Kenya ranks low on Transparency International's Corruption Perception Index (CPI), a metric which attempts to gauge the prevalence of public sector corruption in various countries. In 2012, the nation placed 139th out of 176 total countries in the CPI, with a score of 27/100. However, there are several rather significa... |
In the Presidential elections, President Kibaki under the Party of National Unity ran for re-election against the main opposition party, the Orange Democratic Movement (ODM). The elections were seen to have been flawed with international observers saying that they were below international standards. After a split which... |
Since the election riots, the government and civil society organisations started programmes to avoid similar disasters in the future, said Agnes R. M. Aboum – executive director of TAABCO Research and Development Consultants in Nairobi – in the magazine D+C Development and Cooperation. For example, the Truth, Justice a... |
On 28 February 2008, Kibaki and Odinga signed an agreement on the formation of a coalition government in which Odinga would become Kenya's second Prime Minister. Under the deal, the president would appoint cabinet ministers from both PNU and ODM camps depending on each party's strength in Parliament. The agreement stip... |
The new office of the PM will have power and authority to co-ordinate and supervise the functions of the Government and will be occupied by an elected MP who will be the leader of the party or coalition with majority members in Parliament. The world watched Annan and his UN-backed panel and African Union chairman Jakay... |
A constitutional change was considered that would eliminate the position of Prime Minister and simultaneously reduce the powers of the President. A referendum to vote on the proposed constitution was held on 4 August 2010, and the new constitution passed by a wide margin. Among other things, the new constitution delega... |
In December 2014, President Uhuru Kenyatta signed a Security Laws Amendment Bill, which supporters of the law suggested was necessary to guard against armed groups. Opposition politicians, human rights groups, and nine Western countries criticised the security bill, arguing that it infringed on democratic freedoms. The... |
With International Criminal Court trial dates in 2013 for both President Kenyatta and Deputy President William Ruto related to the 2007 election aftermath, US President Barack Obama chose not to visit the country during his mid-2013 African trip. Later in the summer, Kenyatta visited China at the invitation of Presiden... |
The armed forces are regularly deployed in peacekeeping missions around the world. Further, in the aftermath of the national elections of December 2007 and the violence that subsequently engulfed the country, a commission of inquiry, the Waki Commission, commended its readiness and adjudged it to "have performed its du... |
Kenya’s armed forces, like many government institutions in the country, have been tainted by corruption allegations. Because the operations of the armed forces have been traditionally cloaked by the ubiquitous blanket of “state security”, the corruption has been less in public view, and thus less subject to public scru... |
Although Kenya is the biggest and most advanced economy in east and central Africa, and has an affluent urban minority, it has a Human Development Index (HDI) of 0.519, ranked 145 out of 186 in the world. As of 2005, 17.7% of Kenyans lived on less than $1.25 a day. The important agricultural sector is one of the least ... |
East and Central Africa's biggest economy has posted tremendous growth in the service sector, boosted by rapid expansion in telecommunication and financial activity over the last decade, and now[when?] contributes 62% of GDP. 22% of GDP still comes from the unreliable agricultural sector which employs 75% of the labour... |
Kenya's services sector, which contributes 61% of GDP, is dominated by tourism. The tourism sector has exhibited steady growth in most years since independence and by the late 1980s had become the country's principal source of foreign exchange. Tourists, the largest number being from Germany and the United Kingdom, are... |
Agriculture is the second largest contributor to Kenya's gross domestic product (GDP), after the service sector. In 2005 agriculture, including forestry and fishing, accounted for 24% of GDP, as well as for 18% of wage employment and 50% of revenue from exports. The principal cash crops are tea, horticultural produce, ... |
A consortium led by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) has had some success in helping farmers grow new pigeon pea varieties, instead of maize, in particularly dry areas. Pigeon peas are very drought resistant, so can be grown in areas with less than 650 mm annual rainfall. S... |
Tea, coffee, sisal, pyrethrum, corn, and wheat are grown in the fertile highlands, one of the most successful agricultural production regions in Africa. Livestock predominates in the semi-arid savanna to the north and east. Coconuts, pineapples, cashew nuts, cotton, sugarcane, sisal, and corn are grown in the lower-lyi... |
Although Kenya is the most industrially developed country in the African Great Lakes region, manufacturing still accounts for only 14% of the GDP. Industrial activity, concentrated around the three largest urban centres, Nairobi, Mombasa and Kisumu, is dominated by food-processing industries such as grain milling, beer... |
Kenya's inclusion among the beneficiaries of the US Government's African Growth and Opportunity Act (AGOA) has given a boost to manufacturing in recent years. Since AGOA took effect in 2000, Kenya's clothing sales to the United States increased from US$44 million to US$270 million (2006).[citation needed] Other initiat... |
The largest share of Kenya's electricity supply comes from hydroelectric stations at dams along the upper Tana River, as well as the Turkwel Gorge Dam in the west. A petroleum-fired plant on the coast, geothermal facilities at Olkaria (near Nairobi), and electricity imported from Uganda make up the rest of the supply. ... |
Kenya has proven deposits of oil in Turkana and the commercial viability was just discovered. Tullow Oil estimates Kenya's oil reserves to be around 10 billion barrels. Exploration is still continuing to determine if there are more reserves. Kenya currently imports all crude petroleum requirements. Kenya, east Africa's... |
Published comments on Kenya's Capital FM website by Liu Guangyuan, China's ambassador to Kenya, at the time of President Kenyatta's 2013 trip to Beijing, said, "Chinese investment in Kenya ... reached $474 million, representing Kenya's largest source of foreign direct investment, and ... bilateral trade ... reached $2.... |
In 2007, the Kenyan government unveiled Vision 2030, an economic development programme it hopes will put the country in the same league as the Asian Economic Tigers by the year 2030. In 2013, it launched a National Climate Change Action Plan, having acknowledged that omitting climate as a key development issue in Visio... |
Child labour is common in Kenya. Most working children are active in agriculture. In 2006, UNICEF estimated that up to 30% of girls in the coastal areas of Malindi, Mombasa, Kilifi, and Diani were subject to prostitution. Most of the prostitutes in Kenya are aged 9–18. The Ministry of Gender and Child Affairs employed ... |
Kenya's various ethnic groups typically speak their mother tongues within their own communities. The two official languages, English and Swahili, are used in varying degrees of fluency for communication with other populations. English is widely spoken in commerce, schooling and government. Peri-urban and rural dwellers... |
The vast majority of Kenyans are Christian (83%), with 47.7% regarding themselves as Protestant and 23.5% as Roman Catholic of the Latin Rite. The Presbyterian Church of East Africa has 3 million followers in Kenya and the surrounding countries. There are smaller conservative Reformed churches, the Africa Evangelical P... |
Sizeable minorities of other faiths do exist (Muslim 11.2%, indigenous beliefs 1.7%), and nonreligious 2.4%. Sixty percent of the Muslim population lives in Kenya's Coastal Region, comprising 50% of the total population there. Roughly 4% of Muslims are Ahmadiyya, 8% Shia and another 8% are non-denominational Muslims, w... |
Nurses treat 80% of the population who visit dispensaries, health centres and private clinics in rural and under-served urban areas. Complicated cases are referred to clinical officers, medical officers and medical practitioners. According to the Kenya National Bureau of Statistics, in 2011 there were 65,000 qualified ... |
Diseases of poverty directly correlate with a country's economic performance and wealth distribution: Half of Kenyans live below the poverty level. Preventable diseases like malaria, HIV/AIDS, pneumonia, diarrhoea and malnutrition are the biggest burden, major child-killers, and responsible for much morbidity; weak pol... |
Kenya's first system of education was introduced by British colonists. After Kenya's independence on 12 December 1963, an authority named the Ominde Commission was formed to introduce changes that would reflect the nation's sovereignty. The commission focused on identity and unity, which were critical issues at the tim... |
In 1981, the Presidential Working Party on the Second University was commissioned to look at both the possibilities of setting up a second university in Kenya as well as the reforming of the entire education system. The committee recommended that the 7–4–2–3 system be changed to an 8–4–4 system (eight years in primary,... |
The current 8–4–4 system was launched in January 1985. It put more emphasis on vocational subjects on the assumption that the new structure would enable school drop-outs at all levels either to be self-employed or to secure employment in the informal sector. In January 2003, the Government of Kenya announced the introd... |
Basic formal education starts at age six years and lasts 12 years comprising eight years in primary school and four years in high school or secondary school. Primary school is free in public schools and those who exit at this level can join a vocational youth/village polytechnic or make their own arrangements for an ap... |
The country's literacy level stands at 85% of the whole population. Preschool, which targets children from age three to five, is an integral component of the education system and is a key requirement for admission to Standard One (First Grade). At the end of primary education, pupils sit the Kenya Certificate of Primar... |
Other than the curriculum led learning, there are also National and Public Library Services led by the Kenya National Library Service (KNLS). KNLS is the body mandated to establish, equip, manage and maintain national and public libraries in the country. In addition, some of the counties within the country have either ... |
Kenya is active in several sports, among them cricket, rallying, football, rugby union and boxing. The country is known chiefly for its dominance in middle-distance and long-distance athletics, having consistently produced Olympic and Commonwealth Games champions in various distance events, especially in 800 m, 1,500 m... |
Kenya won several medals during the Beijing Olympics, six gold, four silver and four bronze, making it Africa's most successful nation in the 2008 Olympics. New athletes gained attention, such as Pamela Jelimo, the women's 800m gold medalist who went ahead to win the IAAF Golden League jackpot, and Samuel Wanjiru who w... |
Kenya has been a dominant force in women's volleyball within Africa, with both the clubs and the national team winning various continental championships in the past decade.[citation needed] The women's team has competed at the Olympics and World Championships but without any notable success. Cricket is another popular ... |
In the motor rallying arena, Kenya is home to the world famous Safari Rally, commonly acknowledged as one of the toughest rallies in the world. It was a part of the World Rally Championship for many years until its exclusion after the 2002 event owing to financial difficulties. Some of the best rally drivers in the wor... |
Kenyans generally have three meals in a day – breakfast in the morning (kiamsha kinywa), lunch in the afternoon (chakula cha mchana) and supper in the evening (chakula cha jioni or known simply as "chajio"). In between, they have the 10 o'clock tea (chai ya saa nne) and 4 pm tea (chai ya saa kumi). Breakfast is usually... |
The Intergovernmental Panel on Climate Change (IPCC) is a scientific intergovernmental body under the auspices of the United Nations, set up at the request of member governments. It was first established in 1988 by two United Nations organizations, the World Meteorological Organization (WMO) and the United Nations Envi... |
Korean economist Hoesung Lee is the chair of the IPCC since October 8, 2015, following the election of the new IPCC Bureau. Before this election, the IPCC was led by his vice-Chair Ismail El Gizouli, who was designated acting Chair after the resignation of Rajendra K. Pachauri in February 2015. The previous chairs were... |
The IPCC Panel is composed of representatives appointed by governments and organizations. Participation of delegates with appropriate expertise is encouraged. Plenary sessions of the IPCC and IPCC Working groups are held at the level of government representatives. Non Governmental and Intergovernmental Organizations ma... |
The IPCC receives funding through the IPCC Trust Fund, established in 1989 by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO), Costs of the Secretary and of housing the secretariat are provided by the WMO, while UNEP meets the cost of the Depute Secretary. Annual cash con... |
The IPCC does not carry out research nor does it monitor climate related data. Lead authors of IPCC reports assess the available information about climate change based on published sources. According to IPCC guidelines, authors should give priority to peer-reviewed sources. Authors may refer to non-peer-reviewed source... |
Each chapter has a number of authors who are responsible for writing and editing the material. A chapter typically has two "coordinating lead authors", ten to fifteen "lead authors", and a somewhat larger number of "contributing authors". The coordinating lead authors are responsible for assembling the contributions of... |
The executive summary of the WG I Summary for Policymakers report says they are certain that emissions resulting from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases, resulting on average in an additional warming of the Earth's surface. They calculate with confidence... |
In 2001, 16 national science academies issued a joint statement on climate change. The joint statement was made by the Australian Academy of Science, the Royal Flemish Academy of Belgium for Science and the Arts, the Brazilian Academy of Sciences, the Royal Society of Canada, the Caribbean Academy of Sciences, the Chin... |
IPCC author Richard Lindzen has made a number of criticisms of the TAR. Among his criticisms, Lindzen has stated that the WGI Summary for Policymakers (SPM) does not faithfully summarize the full WGI report. For example, Lindzen states that the SPM understates the uncertainty associated with climate models. John Hought... |
In addition to climate assessment reports, the IPCC is publishing Special Reports on specific topics. The preparation and approval process for all IPCC Special Reports follows the same procedures as for IPCC Assessment Reports. In the year 2011 two IPCC Special Report were finalized, the Special Report on Renewable Ene... |
The IPCC concentrates its activities on the tasks allotted to it by the relevant WMO Executive Council and UNEP Governing Council resolutions and decisions as well as on actions in support of the UNFCCC process. While the preparation of the assessment reports is a major IPCC function, it also supports other activities,... |
This projection was not included in the final summary for policymakers. The IPCC has since acknowledged that the date is incorrect, while reaffirming that the conclusion in the final summary was robust. They expressed regret for "the poor application of well-established IPCC procedures in this instance". The date of 20... |
Former IPCC chairman Robert Watson has said "The mistakes all appear to have gone in the direction of making it seem like climate change is more serious by overstating the impact. That is worrying. The IPCC needs to look at this trend in the errors and ask why it happened". Martin Parry, a climate expert who had been c... |
The third assessment report (TAR) prominently featured a graph labeled "Millennial Northern Hemisphere temperature reconstruction" based on a 1999 paper by Michael E. Mann, Raymond S. Bradley and Malcolm K. Hughes (MBH99), which has been referred to as the "hockey stick graph". This graph extended the similar graph in ... |
These studies were widely presented as demonstrating that the current warming period is exceptional in comparison to temperatures between 1000 and 1900, and the MBH99 based graph featured in publicity. Even at the draft stage, this finding was disputed by contrarians: in May 2000 Fred Singer's Science and Environmental... |
On 23 June 2005, Rep. Joe Barton, chairman of the House Committee on Energy and Commerce wrote joint letters with Ed Whitfield, Chairman of the Subcommittee on Oversight and Investigations demanding full records on climate research, as well as personal information about their finances and careers, from Mann, Bradley an... |
The IPCC Fourth Assessment Report (AR4) published in 2007 featured a graph showing 12 proxy based temperature reconstructions, including the three highlighted in the 2001 Third Assessment Report (TAR); Mann, Bradley & Hughes 1999 as before, Jones et al. 1998 and Briffa 2000 had both been calibrated by newer studies. In... |
On 1 February 2007, the eve of the publication of IPCC's major report on climate, a study was published suggesting that temperatures and sea levels have been rising at or above the maximum rates proposed during the last IPCC report in 2001. The study compared IPCC 2001 projections on temperature and sea level change wi... |
Another example of scientific research which suggests that previous estimates by the IPCC, far from overstating dangers and risks, have actually understated them is a study on projected rises in sea levels. When the researchers' analysis was "applied to the possible scenarios outlined by the Intergovernmental Panel on ... |
Michael Oppenheimer, a long-time participant in the IPCC and coordinating lead author of the Fifth Assessment Report conceded in Science Magazine's State of the Planet 2008-2009 some limitations of the IPCC consensus approach and asks for concurring, smaller assessments of special problems instead of the large scale ap... |
The IPCC process on climate change and its efficiency and success has been compared with dealings with other environmental challenges (compare Ozone depletion and global warming). In case of the Ozone depletion global regulation based on the Montreal Protocol has been successful, in case of Climate Change, the Kyoto Pr... |
According to Sheldon Ungar's comparison with global warming, the actors in the ozone depletion case had a better understanding of scientific ignorance and uncertainties. The ozone case communicated to lay persons "with easy-to-understand bridging metaphors derived from the popular culture" and related to "immediate ris... |
Since the IPCC does not carry out its own research, it operates on the basis of scientific papers and independently documented results from other scientific bodies, and its schedule for producing reports requires a deadline for submissions prior to the report's final release. In principle, this means that any significa... |
In February 2010, in response to controversies regarding claims in the Fourth Assessment Report, five climate scientists – all contributing or lead IPCC report authors – wrote in the journal Nature calling for changes to the IPCC. They suggested a range of new organizational options, from tightening the selection of le... |
Chloroplasts' main role is to conduct photosynthesis, where the photosynthetic pigment chlorophyll captures the energy from sunlight and converts it and stores it in the energy-storage molecules ATP and NADPH while freeing oxygen from water. They then use the ATP and NADPH to make organic molecules from carbon dioxide ... |
Chloroplasts are highly dynamic—they circulate and are moved around within plant cells, and occasionally pinch in two to reproduce. Their behavior is strongly influenced by environmental factors like light color and intensity. Chloroplasts, like mitochondria, contain their own DNA, which is thought to be inherited from... |
Chloroplasts are one of many types of organelles in the plant cell. They are considered to have originated from cyanobacteria through endosymbiosis—when a eukaryotic cell engulfed a photosynthesizing cyanobacterium that became a permanent resident in the cell. Mitochondria are thought to have come from a similar event,... |
Cyanobacteria are considered the ancestors of chloroplasts. They are sometimes called blue-green algae even though they are prokaryotes. They are a diverse phylum of bacteria capable of carrying out photosynthesis, and are gram-negative, meaning that they have two cell membranes. Cyanobacteria also contain a peptidogly... |
Somewhere around a billion years ago, a free-living cyanobacterium entered an early eukaryotic cell, either as food or as an internal parasite, but managed to escape the phagocytic vacuole it was contained in. The two innermost lipid-bilayer membranes that surround all chloroplasts correspond to the outer and inner mem... |
These chloroplasts, which can be traced back directly to a cyanobacterial ancestor, are known as primary plastids ("plastid" in this context means almost the same thing as chloroplast). All primary chloroplasts belong to one of three chloroplast lineages—the glaucophyte chloroplast lineage, the rhodophyte, or red algal... |
The alga Cyanophora, a glaucophyte, is thought to be one of the first organisms to contain a chloroplast. The glaucophyte chloroplast group is the smallest of the three primary chloroplast lineages, being found in only 13 species, and is thought to be the one that branched off the earliest. Glaucophytes have chloroplas... |
Rhodoplasts have a double membrane with an intermembrane space and phycobilin pigments organized into phycobilisomes on the thylakoid membranes, preventing their thylakoids from stacking. Some contain pyrenoids. Rhodoplasts have chlorophyll a and phycobilins for photosynthetic pigments; the phycobilin phycoerytherin is... |
The chloroplastidan chloroplasts, or green chloroplasts, are another large, highly diverse primary chloroplast lineage. Their host organisms are commonly known as the green algae and land plants. They differ from glaucophyte and red algal chloroplasts in that they have lost their phycobilisomes, and contain chlorophyll... |
While primary chloroplasts have a double membrane from their cyanobacterial ancestor, secondary chloroplasts have additional membranes outside of the original two, as a result of the secondary endosymbiotic event, when a nonphotosynthetic eukaryote engulfed a chloroplast-containing alga but failed to digest it—much lik... |
Euglenophytes are a group of common flagellated protists that contain chloroplasts derived from a green alga. Euglenophyte chloroplasts have three membranes—it is thought that the membrane of the primary endosymbiont was lost, leaving the cyanobacterial membranes, and the secondary host's phagosomal membrane. Euglenoph... |
Cryptophytes, or cryptomonads are a group of algae that contain a red-algal derived chloroplast. Cryptophyte chloroplasts contain a nucleomorph that superficially resembles that of the chlorarachniophytes. Cryptophyte chloroplasts have four membranes, the outermost of which is continuous with the rough endoplasmic reti... |
Apicomplexans are another group of chromalveolates. Like the helicosproidia, they're parasitic, and have a nonphotosynthetic chloroplast. They were once thought to be related to the helicosproidia, but it is now known that the helicosproida are green algae rather than chromalveolates. The apicomplexans include Plasmodi... |
Apicoplasts have lost all photosynthetic function, and contain no photosynthetic pigments or true thylakoids. They are bounded by four membranes, but the membranes are not connected to the endoplasmic reticulum. The fact that apicomplexans still keep their nonphotosynthetic chloroplast around demonstrates how the chlor... |
The most common dinophyte chloroplast is the peridinin-type chloroplast, characterized by the carotenoid pigment peridinin in their chloroplasts, along with chlorophyll a and chlorophyll c2. Peridinin is not found in any other group of chloroplasts. The peridinin chloroplast is bounded by three membranes (occasionally ... |
The fucoxanthin dinophyte lineages (including Karlodinium and Karenia) lost their original red algal derived chloroplast, and replaced it with a new chloroplast derived from a haptophyte endosymbiont. Karlodinium and Karenia probably took up different heterokontophytes. Because the haptophyte chloroplast has four membr... |
Members of the genus Dinophysis have a phycobilin-containing chloroplast taken from a cryptophyte. However, the cryptophyte is not an endosymbiont—only the chloroplast seems to have been taken, and the chloroplast has been stripped of its nucleomorph and outermost two membranes, leaving just a two-membraned chloroplast... |
Some dinophytes, like Kryptoperidinium and Durinskia have a diatom (heterokontophyte) derived chloroplast. These chloroplasts are bounded by up to five membranes, (depending on whether you count the entire diatom endosymbiont as the chloroplast, or just the red algal derived chloroplast inside it). The diatom endosymbi... |
Lepidodinium viride and its close relatives are dinophytes that lost their original peridinin chloroplast and replaced it with a green algal derived chloroplast (more specifically, a prasinophyte). Lepidodinium is the only dinophyte that has a chloroplast that's not from the rhodoplast lineage. The chloroplast is surro... |
While most chloroplasts originate from that first set of endosymbiotic events, Paulinella chromatophora is an exception that acquired a photosynthetic cyanobacterial endosymbiont more recently. It is not clear whether that symbiont is closely related to the ancestral chloroplast of other eukaryotes. Being in the early ... |
Chloroplasts have their own DNA, often abbreviated as ctDNA, or cpDNA. It is also known as the plastome. Its existence was first proved in 1962, and first sequenced in 1986—when two Japanese research teams sequenced the chloroplast DNA of liverwort and tobacco. Since then, hundreds of chloroplast DNAs from various spec... |
The inverted repeat regions are highly conserved among land plants, and accumulate few mutations. Similar inverted repeats exist in the genomes of cyanobacteria and the other two chloroplast lineages (glaucophyta and rhodophyceæ), suggesting that they predate the chloroplast, though some chloroplast DNAs have since los... |
The mechanism for chloroplast DNA (cpDNA) replication has not been conclusively determined, but two main models have been proposed. Scientists have attempted to observe chloroplast replication via electron microscopy since the 1970s. The results of the microscopy experiments led to the idea that chloroplast DNA replica... |
In cpDNA, there are several A → G deamination gradients. DNA becomes susceptible to deamination events when it is single stranded. When replication forks form, the strand not being copied is single stranded, and thus at risk for A → G deamination. Therefore, gradients in deamination indicate that replication forks were... |
One of competing model for cpDNA replication asserts that most cpDNA is linear and participates in homologous recombination and replication structures similar to bacteriophage T4. It has been established that some plants have linear cpDNA, such as maize, and that more species still contain complex structures that scien... |
Endosymbiotic gene transfer is how we know about the lost chloroplasts in many chromalveolate lineages. Even if a chloroplast is eventually lost, the genes it donated to the former host's nucleus persist, providing evidence for the lost chloroplast's existence. For example, while diatoms (a heterokontophyte) now have a... |
Curiously, around half of the protein products of transferred genes aren't even targeted back to the chloroplast. Many became exaptations, taking on new functions like participating in cell division, protein routing, and even disease resistance. A few chloroplast genes found new homes in the mitochondrial genome—most b... |
After a chloroplast polypeptide is synthesized on a ribosome in the cytosol, an enzyme specific to chloroplast proteins phosphorylates, or adds a phosphate group to many (but not all) of them in their transit sequences. Phosphorylation helps many proteins bind the polypeptide, keeping it from folding prematurely. This ... |
In land plants, chloroplasts are generally lens-shaped, 5–8 μm in diameter and 1–3 μm thick. Greater diversity in chloroplast shapes exists among the algae, which often contain a single chloroplast that can be shaped like a net (e.g., Oedogonium), a cup (e.g., Chlamydomonas), a ribbon-like spiral around the edges of th... |
There are some common misconceptions about the outer and inner chloroplast membranes. The fact that chloroplasts are surrounded by a double membrane is often cited as evidence that they are the descendants of endosymbiotic cyanobacteria. This is often interpreted as meaning the outer chloroplast membrane is the product... |
The chloroplast double membrane is also often compared to the mitochondrial double membrane. This is not a valid comparison—the inner mitochondria membrane is used to run proton pumps and carry out oxidative phosphorylation across to generate ATP energy. The only chloroplast structure that can considered analogous to i... |
The chloroplast membranes sometimes protrude out into the cytoplasm, forming a stromule, or stroma-containing tubule. Stromules are very rare in chloroplasts, and are much more common in other plastids like chromoplasts and amyloplasts in petals and roots, respectively. They may exist to increase the chloroplast's surf... |
Some chloroplasts contain a structure called the chloroplast peripheral reticulum. It is often found in the chloroplasts of C4 plants, though it has also been found in some C3 angiosperms, and even some gymnosperms. The chloroplast peripheral reticulum consists of a maze of membranous tubes and vesicles continuous with... |
Chloroplasts have their own ribosomes, which they use to synthesize a small fraction of their proteins. Chloroplast ribosomes are about two-thirds the size of cytoplasmic ribosomes (around 17 nm vs 25 nm). They take mRNAs transcribed from the chloroplast DNA and translate them into protein. While similar to bacterial r... |
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