Showing posts with label BOTANY. Show all posts
Showing posts with label BOTANY. Show all posts
Monday, September 8, 2014
Friday, April 8, 2011
IUCN--International Union for Conservation of Nature
IUCN, the International Union for Conservation of Nature, helps the world find pragmatic solutions to our most pressing environment and development challenges. IUCN was founded in October 1948 as the International Union for the Protection of Nature (or IUPN) following an international conference in Fontainebleau, France. The organization changed its name to the International Union for Conservation of Nature and Natural Resources in 1956 with the acronym IUCN (or UICN in French and Spanish). Use of the name “World Conservation Union”, in conjunction with IUCN, began in 1990. From March 2008 this name is no longer commonly used.
IUCN is the world’s oldest and largest global environmental network - a democratic membership union with more than 1,000 government and NGO member organizations, and almost 11,000 volunteer scientists in more than 160 countries.
IUCN’s work is supported by more than 1,000 professional staff in 60 offices and hundreds of partners in public, NGO and private sectors around the world. The Union’s headquarters are located in Gland, near Geneva, Switzerland
IUCN at a glance
● A unique membership association
● Founded in 1948 as the world’s first global environmental organization
● Today the largest professional global conservation network
● A leading authority on the environment and sustainable development
● More than 1,000 member organizations in 140 countries including 200+ government and 800+ non-government organizations
● Almost 11,000 voluntary scientists and experts, grouped in six Commissions
● More than 1,000 professional staff in 60 offices worldwide
● A neutral forum for governments, NGOs, scientists, business and local communities to find pragmatic solutions to conservation and development challenges.Thousands of field projects and activities around the world
● Governance by a Council elected by member organizations every four years at the IUCN World Conservation Congress
● Funded by governments, bilateral and multilateral agencies, foundations, member organizations and corporations
● Official observer status at the United Nations General Assembly
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Recent News
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IUCN in the process of assessing freshwater biodiversity of India
The freshwater biodiversity of the country is being assessed by the International Union for Conservation of Nature (IUCN). It is after a gap of 13 years that the freshwater biodiversity of the country, including fish, molluscs, insects and plants, is being assessed using the IUCN Red List Categories and Criteria. The last such assessment was held in 1997.
The list is considered a comprehensive inventory of the global conservation status of plant and animal species.
It has nine classifications namely extinct, extinct in the wild, critically endangered, endangered, vulnerable, near threatened, least concern, data deficient and not evaluated.
It is estimated that only 13 of the 807 species of freshwater fish found in India have been assessed using the Red list criteria.
India to enlist endangered animal, plant species in Red list
New Delhi, Apr 3 (PTI) In a bid to strengthen its efforts at conservation of endangered plant and animal species, India has decided to initiate the Red listing process on regular basis. A high-level Environment Ministry panel has decided to bring its first report on the country's endangered species -- both plants and animals -- by the end of next year. "To begin with, two documents, one each on 'Red list of Indian Plants' and 'Red list of Indian Animals' would be released during the COP-11 of the Convention on Biological Diversity to be held in New Delhi in October 2012," a Ministry document said. The Red listing process would follow the framework of the International Union for Conservation of Nature (IUCN) regional guidelines and criteria, it said. The document was prepared by the 10-member steering committee, chaired by Jagdish Kishwan, Additional Director General of Forests (Wildlife). Botanical Survey of India (BSI) and Zoological Survey of India (ZSI) would be the focal points for the Red listing of plant and animal species, respectively. The Ministry decided to carry out the Red listing process on a regular basis to end the "paucity of information for the general public on the status, biology and major threats to the endangered species" of the country, which has a staggering variety of flora and fauna. Many organisations are working independently in the country on the Red listing process. The Ministry would provide necessary coordinating mechanism to integrate the efforts of scientific and voluntary organisations into a scientifically acceptable useful output. "The directors of BSI and ZSI would co-opt as many experts -- both individuals and organisations -- as required, to form a core group, each for plants and animal species separately for completion of the Red listing exercise within the stipulated time period," the document said. The Steering Committee would monitor and guide the process of Red listing and the divisions concerned of the Ministry would allocate necessary budgetary provisions for undertaking the exercise. Last month, the Ministry in collaboration with the ZSI, had released a comprehensive document on 'Critically Endangered Animal Species of India'. As per the latest (2011) quantitative evaluation done by the IUCN, there are 57 critically endangered species of animals in India.
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Dhamra Port Project
Promoting Corporate Environmental Responsibility in India
The agreement between IUCN and The Dhamra Port Company Limited (DPCL), a joint venture of Tata Steel and Larsen & Toubro, is an encouraging step forward in promoting corporate environmental responsibility. This acquires even greater importance given the proximity of the port in relation to one of the world’s most important mass-nesting beaches for olive ridley turtles. Given the Tata Group’s commitment to environmental preservation, IUCN believes that engaging with DPCL, in an effort to integrate the highest of environmental standards into the port development and operations, is an exemplary model of contemporary conservation in action.
IUCN and DPCL, signed an agreement in 2007 with the aims of:
- Avoiding, minimizing and mitigating the impacts of Dhamra Port development on turtles and compensating or off-setting any residual impact that cannot be avoided or reasonably mitigated;
- Improving the project’s performance in other aspects of environment, e.g. terrestrial environment as affected by the access roads, railway lines and other secondary developments; and
- Contributing to raising national and global standards for environmentally responsible development of mega projects.
Current initiatives
In addition of serving as secretariat of IUCN India National Committee, the current activities of India programme include:
The Livelihoods and Landscapes Strategy (LLS) is a leverage programme to catalyze the sustainable use and conservation of forest biodiversity and ecosystem services for the benefit of the rural poor.
Mangroves for the Future (MFF ) initiative, which will address long term threats to coastal ecosystems and livelihoods and which will promote investment in conserving coastal ecosystems as development ‘infrastructure’.
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The IUCN Red List of Threatened Species provides taxonomic, conservation status and distribution information on plants and animals that have been globally evaluated using the IUCN Red List Categories and Criteria. This system is designed to determine the relative risk of extinction, and the main purpose of the IUCN Red List is to catalogue and highlight those plants and animals that are facing a higher risk of global extinction (i.e. those listed as Critically Endangered, Endangered and Vulnerable). The IUCN Red List also includes information on plants and animals that are categorized as Extinct or Extinct in the Wild; on taxa that cannot be evaluated because of insufficient information (i.e., are Data Deficient); and on plants and animals that are either close to meeting the threatened thresholds or that would be threatened were it not for an ongoing taxon-specific conservation programme (i.e., are Near Threatened).
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IUCN Protected Area Categories System
Through its World Commission on Protected Areas (WCPA), IUCN have developed seven Protected Area Management Categories that define protected areas according to their management objectives and are internationally recognised by various national governments and the United Nations.
The categories provide international standards for comparing the protected areas in different countries and encourage the planning of protected areas under management aims.
The categories are:
Ia----- Strict Nature Reserve;
Ib----- Wilderness Area;
II------ National Park;
III----- Natural Monument of Feature;
IV----- Habitat/Species Management Area;
V----- Protected Landscape/ Seascape and;
VI---- Protected area with sustainable use of natural resources
Tuesday, March 15, 2011
Chromosomes and Sex
Chromosomes and Sex:
Chromosomes are long, stringy aggregates of genes that carry heredity information. They are composed of DNA and proteins and are located within the nucleus of our cells. Chromosomes determine everything from hair color and eye color to sex. Whether you are a male or female depends on the presence or absence of certain chromosomes.
Human cells contain 23 pairs of chromosomes for a total of 46. There are 22 pairs of autosomes and one pair of sex chromosomes. The sex chromosomes are the X chromosome and the Y chromosome.
Sex Chromosomes:
In human sexual reproduction, two distinct gametes fuse to form a zygote. Gametes are reproductive cells produced by a type of cell division called meiosis. They contain only one set of chromosomes and are said to be haploid.
The male gamete, called the spermatozoan, is relatively motile and usually has a flagellum. The female gamete, called the ovum, is nonmotile and relatively large in comparison to the male gamete. When the haploid male and female gametes unite in a process called fertilization, they form what is called a zygote. The zygote is diploid, meaning that it contains two sets of chromosomes.
Sex Chromosomes X-Y:
The male gametes or sperm cells in humans and other mammals are heterogametic and contain one of two types of sex chromosomes. They are either X or Y. The female gametes or eggs however, contain only the X sex chromosome and are homogametic. The sperm cell determines the sex of an individual in this case. If a sperm cell containing an X chromosome fertilizes an egg, the resulting zygote will be XX or female. If the sperm cell contains a Y chromosome, then the resulting zygote will be XY or male.
Sex Chromosomes X-O:
Grasshoppers, roaches, and other insects have a similar system for determining the sex of an individual. Adult males lack a Y sex chromosome and have only an X chromosome. They produce sperm cells that contain either an X chromosome or no sex chromosome, which is designated as O. The females are XX and produce egg cells that contain an X chromosome. If an X sperm cell fertilizes an egg, the resulting zygote will be XX or female. If a sperm cell containing no sex chromosome fertilizes an egg, the resulting zygote will be XO or male.
Sex Chromosomes Z-W:
Birds, insects like butterflies, frogs and some species of fish have a different system for determining gender. In these animals it is the female gamete that determines the sex of an individual. Female gametes can either contain a Z chromosome or a W chromosome. Male gametes contain only the Z chromosome. Females of these species are ZW and males are ZZ.
Parthenogenesis:
What about animals like most kinds of wasps, bees, and ants that have no sex chromosomes? How is sex determined? In these species, fertilization determines sex. If an egg becomes fertilized it will develop into a female. A non-fertilized egg may develop into a male. The female is diploid and contains two sets of chromosomes, while the male is haploid. This development of an unfertilized egg into an individual is called parthenogenesis.
Sunday, December 5, 2010
Saturday, October 23, 2010
Terms Associated with Parasitic Plants
Autoparasite. A parasitic plant that attaches by means of haustoria to its own tissues. Commonly seen in Cuscuta (dodder), Cassytha, and seedlings of Loranthaceae (Amyema, Macrosolen).
Autotrophic. Capable of feeding oneself, i.e. photosynthetic plants.
Calyculus. A reduced calyx in various Santalales (e.g. Schoepfiaceae, Loranthaceae). Usually present as a toothed, shortly lobed or entire rim around the summit of the ovary. See Dendrophthoe that shows a calyculus as a lobed sheath crowing the the inferior ovary.
Cataphyll. The first-formed, foliar organs (leaves) of the hypocotyl or branch meristems in some members of Santalales (e.g. Olacaceae, Loranthaceae, Viscaceae). This example of cataphylls in Phoradendron (P. reichenbachianum?) has basal cataphylls on the lateral branches as well as pairs of intercallary cataphylls located more distally on those branches.
Cortical Strand. See endophyte.
Diaphragm. The centrally located aperture that occurs at the apex of the perigone tube in Sapria and Rafflesia (but not Rhizanthes).
Ectophyte. The aerial parts of a parasitic plant (e.g. stem, leaves, flowers) that occur outside the host plant; cf. the internal endophyte.
Endophyte. The portion of the haustorium that occurs inside the host tissue. For viscaceous mistletoes, it may be composed of cortical strands that occur within the inner bark and sinkers that are oriented radially and traverse the xylem. See diagram of broom types in Arceuthobium and anatomical section showing sinkers in Arceuthobium pusillum.
Epicortical Root. In mistletoes, adventitious roots (arising from the parasite stem) that traverse the host bark, eventually establishing secondary haustorial connections. Examples: Dendropemon, Macrosolen, Bakerella, Notanthera, Plicosepalus.
Epiparasite. One parasitic plant that forms an obligate haustorial attachment to another parasitic plant. Example: Phoradendron scabberimum on P. longifolium. See also hyperparasite.
Epiphytism. One plant (the "host") used for physical support by another plant. Aerial parasites such as mistletoes can also be considered epiphytes. But, not all epipytes are parasites! For example, this slide shows both orchid (Oncidium) and bromeliad (Tillandsia) epiphytes from Andros Island, Bahamas, neither of which draw nutrients directly from their hosts (they lack haustorial connections).
Facultative Parasite. A hemiparasitic plant that does not require a host to complete its life cycle. Note, however, that in nature, parasitism is nearly always observed. Many members of Orobanchaceae are facultative hemiparasites such as Agalinis, Aureolaria, and Seymeria.
Haustorium. The morphologically modified root which physically connects the parasite to the host. May be a primary haustorium if the radicle apex is directly transformed into a haustorium (e.g. Striga asiatica) or a secondary haustorium formed from tissues other than the radicle apex such as secondary root apices or from lateral positions on the root (e.g. Ximenia, Dasistoma). The haustoria of holoparasites are more complex (see Conopholis, Balanophora, ). This image showing many types of haustoria.
Hemiparasite. A parasite that is photosynthetic (during at least one stage of its life cycle). It obtains water and nutrients from the host xylem. Some advanced hemiparasites (e.g. dwarf mistletoes) also obtain photosynthates from the host phloem. Hemiparasites can be either facultative (e.g. many Orobanchaceae) or obligate (e.g. mistletoes). Figure of Holo- and Hemiparasites.
Heterotrophic. Referring to organisms that do not produce their own food (thus are nonphotosynthetic). Such organisms must then obtain organic compounds from exogenous sources. In the case of parasitic plants, this is another plant. Contrast with autotrophic. Many forms of heterotrophism exist such as saprophytism, myco-heterotropism, and parasitism.
Holdfast. In some mistletoes, a disc-like swelling at the end of the radicle that forms the first attachment to the host. In this example of an autoparasitic Macrosolen seedling, the holdfast is present and a young epicortical root is emerging from it.
Holoparasite. A nonphotosynthetic parasite that obtains water and nutrients from the host xylem and photosynthates from the host phloem. Holoparasitism has evolved ten times in angiosperms as shown on this phylogenetic tree. Examples: Orobanche, Epifagus, Pholisma, Hydnora, Rafflesia, and Balanophora. Figure of Holo- and Hemiparasites
Host. A plant that provides nutrition to an attached parasitic plant.
Host-specific. A relationship whereby a parasitic plant successfully attaches to a limited number of host species. For example, Rafflesia is only known to attach to Tetrastigma.
Hyperparasite. The situation where one parasitic plant occurs facultatively on another parasitic plant of a different species. See Dendropemon emarginatus on Ximenia americana. See also epiparasite.
Insectivorism. Autotrophic plants that trap arthropods with modified roots or leaves. Insectivores have evolved independently in several families, such as Droseraceae, Sarraceniaceae, Nepenthaceae, and Lentibulariaceae. The selective pressure driving the evolution is likely low nitrogen availability.
Mamelon. Also called the ovarian papilla. In the female (carpellate) flowers of mistletoes such as Arceuthobium, an undifferentiated mass of tissue in which the two embryo sacs are embedded. Note, in this situation, no true ovule is formed. The mamelon is also called the placental nucellar complex.
Mistletoe. A term for an aerial parasite in the order Santalales. Thus, it is both a description of plant habit as well as a taxonomic term. Mistletoes have evolved independently five times in Santalales: Misodendraceae, Loranthaceae, Santalaceae s. str., Amphorogynaceae, and Viscaceae. See Vidal-Russell and Nickrent (2008), pdf file HERE.
Mycelium. The vegetative hypha of a fungus. In some parasitic flowering plants such as Rafflesiaceae, the endophytes are reduced to such an extent as to resemble fungal mycelia.
Mycorrhizal. A symbiotic association between the roots of a (woody) vascular plant and a fungus. Two basic types include ectomycorrhizae, which occur only on the root surface and endomycorrhizae where the fungal hyphae occur inside the tree root. This photo from Baird and Riopel (1986, Can. J. Bot. 64:710-717) shows a scanning electron micrograph of a Conopholis americana (squawroot, Scrophulariaceae) seedling initiating a haustorial connection (white arrow) to a micorrhizal root of Quercus.
Myco-heterotrophism. An association whereby a chlorophyllous or achlorophyllous plant obtains nutrients via a mycorrhizal fungus that is attached to a tree root. This may be a temporary or permanent (obligate) association. One may also see these plants called myco-heterotrophic epiparasites or ectomycorrhizal epiparasites. For more on these plants frequently mistaken as haustorial parasites, see the "Strange and Wonderful Myco-heterotrophs" page.
Nodules. Many angiosperms, especially legumes, are able to fix atmospheric nitrogen by enlisting the help of a symbiotic bacterium. These bacteria live in special bumps on the plant roots which are called nodules. The most common type of bacterium to form nodules is the genus Rhizobium. Root nodules are sometimes confused with parasitic plant haustoria.
Obligate Parasite. A plant that must attach to a host to complete its life cycle. All holoparasites are obligate whereas only some hemiparasites are obligate such as mistletoes and Striga asiatica.
Parasite. A symbiotic association whereby an organism obtains at least some of its nutrition directly from another organism. In plants, a restrictive definition includes only parasites with haustorial connections to other plants, not myco-heterotrophs. See also hemiparasite, holoparasite, facultative parasite and obligate parasite.
Pathogen. A parasite that has clear detrimental effects on the host plant. Examples of plant pathogens include Striga, Orobanche, Cuscuta, and Arceuthobium. In contrast, many haustorial parasites result in such small negative effects as to approach a commensalistic relationship. For example, beechdrops (Epifagus) is a parasite on beech trees but cannot really be called a pathogen.
Perigone. In some members of Rafflesiaceae (Rafflesia, Sapria, and Rhizanthes), the perianth is referred to as the perigone. It is composed of a perigone tube and perigone lobes.
Resistance. A feature or features of a plant that prevent it from serving as a host to a parasitic plant. This resistance may be manifested prior to or after initial haustorial attachment.
Root Grafting. Adjacent roots of the same or different woody plants can become attached by means of cambial growth.
Saprophytism. An organism that obtains its food from decaying organic matter. Technically, no flowering plants are saprophytes, only fungi. See myco-heterotrophism.
Sinker. See endophyte.
Susceptible. A feature or features of a plant that allow it to serve as a host to a parasitic plant.
Symbiosis. A general biological term referring to at least two organisms living together. The participants are called symbionts. Includes more specific associations such as parasitism, mutualism, neutralism (parasymbiosis), commensalism, etc.
Systemic infection. An infection of a host by a parasitic plant whereby the growth of the endophyte keeps pace with the growth of the host meristem. Also called isophasic growth. Can be seen in some dwarf mistletoes (Arceuthobium pusillum, A. douglasii) and Pilostyles.
Viscin. A complex material covering the seeds of most mistletoes. Composed of two parts: 1) a mucilaginous pectic material that accounts for the stickiness and water-holding capacity of the viscin (oligo-D-galacturonic acid and 2) helical strands composed of cellulose. See Paquet et al. (1986, Bot. Gaz. 147:156-158). Example: Phoradendron serotinum.
Witches' broom. An dense aggregation of host branches that is hormonally induced by the presence of fungal or mistletoes such as Arceuthobium. Sometimes simply called a "broom." In Arceuthobium, two basic types occur: nonsystemic brooms, such as in A. tsugense where the parasite endophyte does not ramify within the host tissue and systemic brooms, as in A. pusillum where the endophyte meristem occurs near and divides in synchrony with the host meristem.
Woodrose. A distortion of the host secondary xylem (wood) induced by a parasitic plant haustorium. The haustorium causes the host cambium to increase the amount of wood deposited resulting in a placenta-like structure. The shape of the woodrose will vary depending upon the parasite/host combination and may assume a columnar, conical or saddle shape. When the parasite tissue dies away, all that is left is the host xylem, hence woodroses are made up entirely of host tissue. In the Old and New World tropics, mistletoe woodroses are sold as curiosities and are often carved into ornate works of art. This photo shows a woodrose formed by an unidentified member of Loranthaceae and a carving of a lizard made from a similar one. Woodroses are even formed by the balanophoraceous holoparasite Dactylanthus.
Botany Q.Bank
- Gynostemium-The column, or technically the gynostemium, is a reproductive structure that can be found in several plant families: Aristolochiaceae, Orchidaceae, and Stylidiaceae. It is derived from the fusion of both male and female parts (stamens and pistil) into a single organ. This means that the style and stigma of the pistil, with the filaments and one or more anthers, are all united.
Thursday, October 21, 2010
Protein synthesis
1. INITIATION
- Assembly of active ribosome by placing the first mRNA codon (AUG or START codon) near the P site and pairing it with initiation tRNA, fMet-tRNAfMet.
- Occurs once per polypeptide chain or molecule.
2. ELONGATION
- Involves three distinct steps for each mRNA codon or amino acid in the new polypeptide chain:
- Occurs multiple times per polypeptide.
- 1. Transfer of proper aminoacyl-tRNA from cytoplasm to A-site of ribosome.
2. Covalent linkage of new amino acid to growing polypeptide chain - peptidyl transfer.
3. Movement of tRNA from A-site to P-site and simultaneous movement of mRNA by 3 nucleotides - translocation.
3. TERMINATION
- Reading of final mRNA codon (STOP codon) and dissociation of polypeptide from ribosome.
- Occurs once per polypeptide chain.
ELONGATION OF PROTEIN SYNTHESIS
- 3 distinct steps to add one amino acid to the growing polypeptide chain.
- Occurs many times per polypeptide, the number of which depends upon the number of mRNA codons or amino acids in the protein
- The Elongation Cycle is similar in prokaryotes and eukaryotes.
- Fast: 15-20 amino acids added per second
- Accurate: 1 mistake every ~10,000 amino acids
Transfer of Aminoacyl-tRNA
- Non-initiator, aminoacyl-tRNA is placed in the ribosomal A-site over the mRNA codon in such a way that base pairing occurs between the anticodon loop of the tRNA and mRNA codon (see lecture 1).
- EF-Tu binds GDP and GTP and is a model G protein.
- EF-Ts exchanges GDP for GTP on EF-Tu.
Aminoacyl-tRNA transfer is facilitated by two soluble protein transfer factors, called elongation factors, EF-Tu and EF-Ts in prokaryotes:
The elongation factors are similar in eukaryotes. Instead of two proteins, there is a stable trimer, eEF1-alpha-beta-gamma, which carries out the same function as EF-Tu and EF-Ts. eEF1-alpha is the eukaryotic equivalent of EF-Tu, and eEF1-beta-gamma the eukaryotic equivalent of EF-Ts.
EF-Tu-GDP is the inactive form. EF-Ts activates EF-Tu by catalyzing the exchange of GDP for GTP. EF-Tu-GTP is the active form which binds to non-initiator tRNAs to which the aminoacyl group has been attached.
EF-Tu-GTP-aminoacyl-tRNA is then carried to the ribosome. The complex binds to the ribosome, with the aminoacyl-tRNA in the A-site. Ribosome binding stimulates GTP hydrolysis and EF-Tu-GDP dissociates from the ribosome, free to recycle through the step multiple times.
EF-Tu is partially responsible for the high degree of accuracy of protein synthesis via a mechanism called kinetic proofreading. The error rate of protein synthesis is only 1 wrong amino acid for every 10,000 amino acids added to polypeptides.
When a charged tRNA is positioned into the A-site, the anticodon must base pair with the mRNA codon. If there is an incorrect match, the incorrect aa-tRNA dissociates from the ribosome before GTP hydrolysis occurs. If there is a correct match, GTP hydrolysis occurs and EF-Tu-GDP leaves the ribosome before the cognate aminoacyl-tRNA can dissociate and EF-Tu-GDP dissociates instead, leaving the correct tRNA on the ribosome.
EF-Tu is so important to cellular function that it is one of the most abundant cytoplasmic proteins (>5%). There is one copy of the EF-Tu protein for each tRNA molecule in the cell.
ELONGATION OF PROTEIN SYNTHESIS (cont.)
Peptidyl Transfer or Transpeptidation
- Next, the growing polypeptide chain on the P-site tRNA (peptidyl tRNA) is covalently linked to the amino acid attached to the A-site tRNA, that is a peptide bond is formed. The P-site tRNA is now unacylated and the A-site tRNA is covalently linked to the growing polypeptide chain. This step is somewhat of a mystery but is believed to be catalyzed by a region of the 50S subunit, called the peptidyltransferase complex. The complex utilizes both proteins and 23S rRNA. There is growing evidence that 23S rRNA actively catalyzes the peptidyl transfer step but the mode of action is yet unknown.
- The A-site tRNA with the growing polypeptide chain is then moved within the ribosome to the P-site while the deacylated P-site tRNA is moved to the E-site. Simultaneously, the mRNA is shifted by exactly 3 ribonucleotides or 1 codon.
The process requires a soluble protein factor, called elongation factor EF-G. EF-G is similar, but much larger than EF-Tu. EF-G is also active as the GTP complex.
Although many older texts report that the binding of EF-G-GTP to the ribosome provides the energy for translocation, it is now known to be wrong. The energy derived from GTP hydrolysis drives translocation.
After GTP hydrolysis, EF-G-GDP is released from the ribosome, the tRNA carrying the polypeptide chain is in the P site, and the next mRNA codon is in the A site. The ribosome is now ready to start the elongation cycle over again to add a new amino acid, until a termination signal is reached. It appears that EF-G catalyzes its own exchange of GDP and GTP. No soluble guanine nucleotide exchange factor has yet been found. The equivalent of EF-G in eukaryotes is eEF2.
Chain elongation in prokaryotic translation
The elongation process is depicted as a cycle. Following translocation (step 3) and empty tRNA release (step 4), the ribosome is ready to accept the next aminoacyl tRNA (aa-tRNA) and repeat the cycle. This cycle will continue until a STOP codon is reached.
initiation of protein synthesis in prokaryotes
Formation of the 70S initiation complex
Schematic of the initiation of protein synthesis in prokaryotes
1. Binding of IF1 & IF3 to an empty 70S ribosome dissociates it into 50S and 30S subunits.
2. a. 5' region of mRNA binds to 16S rRNA of free 30S ribsomal subunit, IF3 is released.
- b. Initiator fMet-tRNAfMet carried by IF2-GTP binds to P site of 30S ribsomal subunit.
Certain details of the process remain uncertain. For example, the exact order of binding of IF1, IF2, IF3, tRNA, and mRNA is unclear. The above is one model.
Next: Initiation of translation in eukaryotes
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Fruits - Edible part
1
Apple, pear, Strawberry
Fleshy thalamus
2
Almond and Walnut
Seed
3
Banana
Mesocarp and Endocarp
4
Coconut
Endosperm
5
Cucumber
Placentae, seeds pericarp
6
Custard Apple and Grape
Pericarp
7
Pea and Beans
Cotyledon of seeds
8
Lemon and orange
Juicy hairy endocarp
9
Litchi
Fleshy aril
10
Maize, Wheat
Endosperm
11
Mango, Melon, Pappaya, Watermelon
Mesocarp
12
Pomegranate
Fleshy and juicy seeds
13
Pear, Strawberry
Thalamus
14
Tomato
Whole fruit
15
Mulberry
Peduncle and perianth
16
Pineapple
Receptacle, bract and perianth
17
Jack Fruits
Bracts, perianth and seeds
Wednesday, October 20, 2010
Plant Physiology some important Fact
1. The number of A.T.P. molecules required to initiate beta-oxidation is 2ATP molecule,
2. The growth hormones responsible for Bolting — Gibberellins.
3. The final electron acceptor in pseudocyclic electron transport in chloroplast is — Oxygen.
4. Photolysis of water during photosynthesis occurs with the help of — PS-II.
5. Lock and Key Theory of enzyme structure and function was proposed by — Fischer.
6. The photosynthetic evolution of oxygen requires — Mn enzyme.
7. The terminal electron acceptor released from PS- II is Chl-A-273 or Pheophytine ( Chl.A without Mg)
8. The isotopes that have proved useful research on photosynthesis are C-14 & O-18
9. Ths plant which flowers only once in life time are termed as Monocarpic.
10. AcetyCO-A is the connecting link between — Glycolysis & Kreb cycle.
11. The formula for Chitin C-22 H-54 N-4 O-21
12. The process of release of water through an intact plant is called — Guttation.
13. The enzymes which occur in multiple molecular form within a plant system are called — Isoenzyme.
14. The term Apoplast and Symplast were used first by — Munch.
15. A flash of light in the dark inhibits flowering in —Short Day Plant.
16. The role of inorganic elements in plant growth was at first indicated by — Knoop.
17. Cyclic photophosphorylation is associated with - PS-1
18. The hormone which has negative effect on apical dominance is —Cytokinin.
19. The pigment responsible for germination of light sensitive seeds is known as — Phytochrome.
20. The phytohoromone which is supposed to be one of the factors responsible for regulating the opening and closing of stomata — AB Acid.
21. Seed Dormancy helps the plants in —Overcoming unfavorable climatic condition.
22, The enzyme inactivated by oxygen — Nitrogenase.
23._The enzyme concerned with Ammonia assimilation — Glutamine synthetase.
24. Some flowers open during the day and close at night. This is known as —Photonasty.
25. Anaerobic respiration - takes place in — Cytoplasm.
26. The pigment concerned with both floral induction and seed germination is — Phytochrome.
27. The substrate for photorespiration is — Glycolate.
28. The chief function of seive tube element is — to translocate the organic material from source to sink.
29. Substance related to photoropism is Auxin.
30. The process of oxidative phosphorylation takes place in — Mitochondria.
31 The induction of formation of Interfascicular cambrium is by — Kinetine.
32. The technique & experimental --- organism used by calvin for calvin cycle were — Radioactive Isotope technique and Chlorella & Syndesmous.
33. In the respiratory electron transport system the final acceptor of electron is —Oxygen.
34. The green wavelength of sunlight is absorbed by —Phycoerythrin.
35. In the photosynthetic electron transport system the hydrogen transporter is —Plastoquinone.
36. The water uptake by germinating seed is mainly attributed to — Imbibition.
37. The source of ATP for symbiotic Nitrogen fixation in the root nodules is — Pyruvate.
38. The coenzyme involved in transamination reaction is — Pyridoxal phosphate.
39. A plant growth regulator related with me inhibition of senescence is Gibberallic Acid.
40. The copper containing protein involved in electron transfer from PS- II—PS-I during photosynthesis — Plastocyanin.
41. the final product of beta-oxidation in plants — Acetyl CO-A.
42. The first CO2 acceptor in C4 plants — PEP
43. the mesophyll cells of CAM plants, CO2 fixation during day occurs
through – RUDP carboxylase.
44. Tracer elements are — Radioisotope
45. Plastocyanin is a metalo protein that contains —Copper.
46. The light absorbed by phycocyanin pigment is at the wavelength of — 620 nm
47. The Hydrogen donor in bacterial photosynthesis — H2S here only PS-I is found Pig B-890
48. The apparatus commonly used to measure the rate of transpiration is — Potometer.
49. The first electron acceptor in photosystem — I of Cyclic photo-phosphorylation is —Ferrodoxin,
50. The phytohormone involved in the de novo synthesis of a-amylase in germinating barley seeds is — Gibberellin.
51. In C4 plants NO3- assimilation occurs in — Bundle.sheeth cells.
52. Bundle sheath cells Chloroplast are large without grana. while mesophyll Chloroplast are smaller with grana.
Thursday, May 6, 2010
International Botanical Congress
International Botanical Congress (IBC) is a large-scale meeting of botanists in all scientific fields, from all over the world. Authorized by the International Association of Botanical and Mycological Societies (IABMS), congresses are held every six years with the venue circulating around the world. The latest was the XVII IBC in Vienna, a hundred years after the second congress, II IBC, and the next will be held in Melbourne, Australia, 24-30 July 2011[1].
The IBC has the power to alter the ICBN. Formally the power resides with the Plenary Session, but in practice this just approves the decisions of the Nomenclature Section. The Nomenclature Section meets before the actual Congress and deals with all proposals to modify the ICBN: this includes ratifying recommendations on conservation. To reduce the risk of a hasty decision the Nomenclature Section adopts a 60% majority as needed for any change.
Year | City | Country | |
I | 1900 | ||
II | 1905 | ||
III | 1910 | ||
IV | 1926 | ||
V | 1930 | ||
VI | 1935 | ||
VII | 1950 | ||
VIII | 1954 | ||
IX | 1959 | ||
X | 1964 | ||
XI | 1969 | ||
XII | 1975 | ||
XIII | 1981 | ||
XIV | 1987 | ||
XV | 1993 | ||
XVI | 1999 | ||
XVII | 2005 | ||
XVIII | 2011 |
HERBAL PLANTS
Amla
(Emblica officinalis)
The richest source of vitamin C, Amla is
useful in throat and respiratory tract
infections. It protects cells from free radical
damage.
Arjuna
(Terminalia arjuna)
The bark of tree is a cardiac stimulant and
has a cooling and tonic effect. It is useful in
arresting secretion or bleeding. It helps to
relieve fever. It is also useful in removing
calculi or stones formed in the urinary
system, in promoting flow of bile and in the
healing of wounds. Asthma, acne, diarrhea
or dysentery, earache.
Ashwagandha
(Withania somnifera)
It is also called as Indian Ginseng. It has
been used in various diseases such as
leprosy, nervous, disorders, intestinal
infections. Of late it has gained importance
because of its property to increase
resistance to stress and build greater
physical endurance.
Babchi
(Psoralea corylifolia)
The seeds are useful in bilious affection &
to make perfumed oil. The powder is used
in treatment of skin disease such as
leucoderma & leprosy. It is used in treating
psoriasis. It is also used in the
manufacture of agarbathis because of its
aromatic smell.
Baheda
(Terminalia belerica)
It is used in coughs, sore throat and
dyspepsia. It is one of the constituents of
triphala, which finds use in hair care,
diseases of liver and gastro-intestinal tract.
It is also a mild laxative and demulcent.
Brahmi
(Bacopa monnieri)
A well known herb that helps in improving
alertness. Brahmi also acts as an antianxiety
agent and has a calming effect.
Chopchini
(Smilax china)
Roots are aphrodisiac, pseudorific,
demulent, alteratively used in rheumatism,
syphilis, and skin diseases. The rhizome is
made into a paste and applied to painful
swellings.
Dioscorea
(Dioscorea floribunda)
It is used as anti-inflammatory, anabolic,
antifertility, Antiarthritic.
Geloy
(Tinaspora cordifolia)
It is used in fevers, dyspepsia, general
debility and urinary diseases. It is also
used in rheumatism, jaundice, arthritis and
diabetes.
Ghritkumari
(Aloe vera)
emmenogogue and antheimintic, cough,
colds, piles, debility, dyspnoea, asthma
and jaundice.
Harad
(Terminalia chebula)
It is used in cough, asthma and urinary
diseases. It is one of the ingredients of
Triphala along with Amla and Behra. Used
in treatment of piles. It is also used in
tanning of leather.
Kalmegh
(Andrographis
paniculata)
The decoction of the plant is a blood
purifier. It is used as a cure for torpid liver
and jaundice. It is a major constituent of
the Ayurvedic preperation switradilepa
which in effective in treating vitiligo. The
plant is also extracted for Andrographolide.
Karanj
(Pongamia glabra)
Seeds contain 27% bitter and dark (sherry)
coloured fixed oil (pongamia oil). The oil
contains toxic flavonoids including 1.25%
karanjin and 0.85% pongamol alkaloid,
resin, mucilage and sugar. Seed extract is
used for Skin problems, in tanning, Shops,
infestation of grains, piscidal, insecticidal,
nematicidal and bactericidal activity.
Kucchila
(Strychnos
nuxvomica)
It is the important source of alkaloids,
brucine and strachnine. These alkaloids
find importance in manufacture of high
value drugs to treat muscles and the spinal
chord. It is highly intoxicating in natural
form. It has a marked effect on the
nervous system.
Lasuna (Garlic)
(Allium sativum)
Lasuna helps in controlling the excess
conversion of lipids and cholesterol.
Mishamitita
(Coptis teeta)
Improves appetite, restores digestion, gas,
visceral obstructions, jaundice,improves
bile flow, chronic gall bladder inflammation,
debility, convalescence after fevers,
debilitating diseases, atonic indigestion,
mild forms of intermittent fevers, catarrhal
and rheumatic conjunctivitis, dries
excessive body moisture (e.g., water
retention), all Pitta disorders, anal fissure,
ulcerative colitis, vaginal infections,
tumors, boils, carbuncles, inflammatory
skin conditions, externally applied to sores
(including mouth sores).
Neem
(Azadirachta indica)
It has anti-bacterial, anti-fungal and blood
purifying properties. Neem is very useful in
skin disorders and helps maintain a
healthy, beautiful and glowing skin.
Pippali
(Piper longum)
It has paralytic bronchial asthma. chronic
malaria Haematinic,
diuretic,digestive,inflammation of
liver,pains in joint, piles lumbago,
snakebite, scorpion sting, night blindness,
insomnia, worms.
Safed Musli
(Chlorophytum
borivilianum)
It has aphrodiasiac properties & vitalizer.
It is used for Diabetes,Arthritis, curative
for Natal & post-natal problems,
Rheumetism and Joint Pains, powerful
uterine stimulant, for the preparation of
nutritive tonic used in general sexual
weakness.
Sarpagandha
(Rauvolfia serpentina)
It is used for Instanity, schizoprenia,
epilepsy, blood pressure, sedative, snake
bite, Hypertension, insomnia.
Seetaphal
(Annona squamosa)
Roots are powerful purgative and are
useful in mental depression and spinal
disorder. Leaves are insecticidal. Fruits are
sedative, stimulant, expectorant and tonic.
They are also useful in anemia, burning
sensation, vomiting, cough, malignant,
tumours and strengthening the muscles.
Seeds have very powerful insecticidal
properties.
Sunth
(Zingiber officinale)
It is used for Gastrointestinal disorder,
Bronchial asthma, anti-inflammatory effect.
The antirheumatic, Antihistaminic,
antiemetic and antivertigo, nausea and
dyspepsia.
Talispatra
(Taxus baccata)
It is the source of the anti-cancer alkaloid
"Taxol". It is also used in treatment of
asthma, haemoptysis and epilepsy.
Tulasi
(Ocimum sanctum)
Tulasi has anti-micribial and antiinflammatory
properties, and is useful in
respiratory tract infections like dry or wet
cough, cold and sore throat.
Vach
(Acorus calamus)
Calamus rhizome is used in the form of
powder and balms. It is used as an
insecticide for the distruction of fleas,
bedbugs, moths, lice etc. It is used in the
treatment of diarrhoea and worms in
children. The rhizome is also used to make
calamus oil, which has a pleasant odour.
Wednesday, May 5, 2010
Botany solution UPPSC pre 2010 Part-2
- Species Plantarum ("The Species of Plants") was first published in 1753, as a two-volume work by Carl Linnaeus. Its prime importance is perhaps that it is
- The androecium in Coccinia grandis (L.) Voigt. is described. There are three free bithecous stamens each with a single vascular strand.
- Cucurbitaceae, Coccinia grandis (L.) Voigt., androecium, free bithecous stamens
We encounter special forms of stamen fusion in the Cucurbitaceae, whose flowers are normally ... Five free stamens are only rarely found here (Fevillea).
- The size of the cycad leaf is variable; Zamia pygmaea, the smallest cycad, has leaves about 20–30 centimetres long,
- a plant that grows on ice or snow, esp. various algae and fungi. Etymology: cryo- + -phyte. Browse dictionary definitions near cryophyte ...
- Family, Characeae. Genus, Chara. Size, Stem length: up to 50cm ... The stonewort anchors itself, not with roots like a plant, but with rhizoids, colourless
- recommendations to use the ending -phytina for subdivisions
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