Cytoskeleton Anatomy, Function, and Structure

The cytoskeleton is a network of fibers forming the infrastructure of eukaryotic cells, prokaryotic cells, and archaeans. In eukaryotic cells, these fibers consist of a complex mesh of protein filaments and motor proteins that aid in cell movement and stabilize the cell. Cytoskeleton Function The cytoskeleton extends throughout the cells cytoplasm and directs a number of important functions. It helps the cell maintain its shape and gives support to the cell.A variety of cellular organelles are held in place by the cytoskeleton.It assists in the formation of vacuoles.The cytoskeleton is not a static structure but is able to disassemble and reassemble its parts in order to enable internal and overall  cell mobility. Types of intracellular movement supported by the cytoskeleton include transportation of vesicles into and out of a cell, chromosome manipulation during mitosis and meiosis, and organelle migration.The cytoskeleton makes cell migration possible as cell motility is needed for tissue construction and repair, cytokinesis (the division of the cytoplasm) in the formation of daughter cells, and in immune cell responses to germs.The cytoskeleton assists in the transportation of communication signals between cells.It forms cellular appendage-like protrusions, such as cilia and flagella,  in some cells. Cytoskeleton Structure The cytoskeleton is composed of at least three different types of fibers: microtubules, microfilaments, and intermediate filaments. These fibers are distinguished by their size with microtubules being the thickest and microfilaments being the thinnest. Protein Fibers Microtubules are hollow rods functioning primarily to help support and shape the cell and as routes along which organelles can move. Microtubules are typically found in all eukaryotic cells. They vary in length and measure about 25 nm (nanometers) in diameter.Microfilaments or actin filaments are thin, solid rods that are active in muscle contraction. Microfilaments are particularly prevalent in muscle cells. Similar to microtubules, they are typically found in all eukaryotic cells. Microfilaments are composed primarily of  the contractile protein actin and measure up to 8 nm in diameter. They also participate in organelle movement.Intermediate filaments can be abundant in many cells and provide support for microfilaments and microtubules by holding them in place. These filaments form keratins found in epithelial cells and  neurofilaments in neurons. They measure 10 nm in diameter. Motor Proteins A number of motor proteins are found in the cytoskeleton. As their name suggests, these proteins actively move cytoskeleton fibers. As a result, molecules and organelles are transported around the cell. Motor proteins are powered by ATP, which is generated through  cellular respiration. There are three types of motor proteins involved in cell movement. Kinesins move along microtubules carrying cellular components along the way. They are typically used to pull organelles toward the cell membrane.Dyneins are similar to kinesins and are used to pull cellular components inward toward the nucleus. Dyneins also work to slide microtubules relative to one another as observed in the movement of cilia and flagella.Myosins interact with actin in order to perform muscle contractions. They are also involved in cytokinesis, endocytosis (endo-cyt-osis), and exocytosis (exo-cyt-osis). Cytoplasmic Streaming The cytoskeleton helps to make cytoplasmic streaming possible. Also known as cyclosis, this process involves the movement of the cytoplasm to circulate nutrients, organelles, and other substances within a cell. Cyclosis also aids in endocytosis and exocytosis, or the transport of substance into and out of a cell. As cytoskeletal microfilaments contract, they help to direct the flow of cytoplasmic particles. When microfilaments attached to organelles contract, the organelles are pulled along and the cytoplasm flows in the same direction. Cytoplasmic streaming occurs in both prokaryotic and eukaryotic cells. In protists, like amoebae, this process produces extensions of the cytoplasm known as pseudopodia. These structures are used for capturing food and for locomotion. More Cell Structures The following organelles and structures can also be found in eukaryotic cells: Centrioles: These specialized groupings of microtubules help to organize the assembly of spindle fibers during mitosis and meiosis.Chromosomes: Cellular DNA is wrapped in thread-like structures called chromosomes.Cell Membrane: This semi-permeable membrane protects the integrity of the cell.Golgi Complex: This organelle manufactures, stores, and ships certain cellular products.Lysosomes: Lysosomes are sacs of enzymes that digest cellular macromolecules.Mitochondria: These organelles provide energy for the cell.Nucleus: Cell growth and reproduction are controlled by the cell nucleus.Peroxisomes: These organelles help to detoxify alcohol, form bile acid, and use oxygen to break down fats.Ribosomes: Ribosomes are RNA and protein complexes that are responsible for protein production via translation.

Of Mice and Men - Critical Evaluation Essay examples

The main theme of ‘Of Mice and Men by John Steinbeck is fate . The techniques he uses such as the title , repetition , echoes and symbolism are very successful in putting across his very pessimistic views on this theme . br brThe two main characters , George and Lennie , share a dream . George dreams of a piece of land of his own . Independence . A couple of acres , a cow and some pigs . Lennie dreams of tending rabbits . With the title ‘Of Mice and Men , Steinbeck is telling you that this dream whilst on the verge of realization , will be destroyed by fate . br brIt relates to Robert Burns poem ‘To a Mouse . Burns and Steinbeck share the same pessimistic views on fate . In ‘To a Mouse Burns shows that he believes that just as†¦show more content†¦br brThe introduction of Curleys wife adds another piece to the puzzle . Her description when she was standing at the doorway with her ‘rouged lips , ‘ hair hung in little rolled clusters and ‘cotton house clusters shows that she will be the one who destroys George and Lennies dream . This technique is simple but very effective . br brGeorge had told Candy of his dream and Candy wanted in on it . Candy had the money to purchase the land required from compensation received after his arm had been cut off by machinery . This moved them to the verge of achieving their dream . br brIn my view the most successful technique in illustrating John Steinbecks view of fate is the symbolism in the last chapter . ‘A watersnake glided smoothly up the pool , twisting its periscope head from side to side , and it swam the length of the pool and came to the legs of a motionless heron that stood in the shallows . A silent head and beak lanced down and plucked it out by the head , and the beak swallowed the little snake while its tail waved frantically ‘. The heron , motionless and waiting , represents fate while the watersnake , helpless and unaware , is its victim . br brSteinbecks view on fate is illustrated again by the word choice . Words like lanced , plucked and waiting suggest that Steinbeck believes that fate striking is almost medical ; sure and precise . br brThe watersnake could represent almost anyone in the novel although it is most likelyShow MoreRelatedThe Endocrinology Of Male And Female Reproduction1447 Words   |  6 PagesReproductive physiology is comprised of many tightly coordinated functions of the endocrine system including the hypothalamus, pituitary and reproductive organs whose dynamic function plays several critical roles in growth and development as well was reproduction. The hypothalamic-pituitary-gonadal axis plays a critical role in the development and regulation of the reproductive system. 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Nike Incorporation Free Essays

Nike is a world class company that manufactures and markets a wide large of sports equipments such as sports, balls, t-shirts, tracks, uniforms for various sporting activities such as football, basketball, athletics, cricket, tennis and golf. The company was in incorporated in the year 1968 in the state of Oregon, it main business being to design and manufacture the best foot wear and other accessory products. But, Nike has grown to be a world class company that sells well branded and expensive products that are well known for their high quality. We will write a custom essay sample on Nike Incorporation or any similar topic only for you Order Now Nike trademark of â€Å"just do it† is well known, and it relates to the sporting spirit. The company has more than 500 plants in more than 45 countries.[1] Nike did not experience much competition until in 1980s and 90s when Reebok and European counterparts Adidas and Puma entered the market. But Reebok was purchased by Adidas in 2006 thus Adidas is the one giving Nike competition. Nike has been the main player on the footwear market until then, the company controlled about 30% of the United States market, Reebok enjoyed about 20% followed by other companies like Adidas and Puma. Nikes abroad sales went up to $2 billion by 1995 and were leading by having 40% of total sales in footwear. [2] The marketing strategy of Nike has been the biggest success of the company. Nike has premium brands, and offers the market high quality and expensive products. The company creates a brand image which is achieved by the unique logo of a (tick) and a slogan of â€Å"just do it† which attracts lots of customers. The company also does promotional activities of its products by entering into sponsorship deals with world class football stars, celebrity athletes, national teams, and also college athletic. Nevertheless Nike has mixed it marketing strategies and has more elements more than promotion.   This other elements are; competitive price, wide range of products, numerous outlets and retailers (more than 20,000), sponsorship and promotion activities. Currently, Nike has a market share of around 37% in the world. The main objective of Nike is to become a leading sport equipment manufacturer in the world and maintain these standards in future. The major client base is the youth and the young adults who mainly buy the sports products from the company. The company has put a lot of attention on products for men, women, and children, and their children’s shoes are now doing very well on the market currently.   The company has created more market by venturing into various market segments and manufacturing more various products. To achieve its objective of being the leader in market business the company is exploiting new markets outside Europe. Nike has also managed to control its market by acquiring other small companies and turning them to manufacture their products. Like in 1998 it’s purchased Cole Hann which was making informal dress and shoes for $180 and cached a base of young people and their sales went up at 23% making a profit of $ 100 millions in 1998. Nike has continued to improve in its brand and marketing and its objective of being â€Å"the greatest sports and fitness company in the world† alongside world class companies like Coca-Cola. Nike gets contracts with individual clients, cooperate clients and even countries and states. The company supplies to them different products, they can be football uniform for a national team, tracksuits for national athletic teams or even tailor made shoes or uniform for specific football stars such as Ranaldhno of Brazil. [3]The market is divided in various segments which can be viewed according to the region There have been many challenges faced by Nike on the marketing side and Nike has done a lot of to recapture the market. These initiatives that Nike undertook was such as creating an ACG (all- conditions gear) unit and Techlab which was meant to market a brand of sports technology products. Such like digital audio player and waist compass these projects were meant to capture sales. In the beginning of 1999 Nike launched its products on the internet and they were directly available to the customers. Nike has continued to expand its market and with a strong marketing team lead by Mr. Perez who has vast experience, the company in 2004, posted profits of more than $1 billion. [4] The company has a high team of human resources managers who are responsible for building a workforce which is effective and efficient. This managers build teams develop the necessary talents that are seriously needed by the organization to perform their duties. The managers also inspire, mentor, set examples, innovate and revolutionize all the employees in order to achieve the best from them. The employees also attend refresher courses seminars and training to keep them in touch with new market trends and technological advancements. In general the public attitude towards the company is good, but the people of Beaverton where the company feel that it should be annexed fro where its headquarters are in Oregon State. But the company feels that the annexing will cost it $700,000 every year in terms of added taxes. The company objective is achieved through proper marketing and advancement in technology by creating high quality products and designing better management approaches to maintain the market. Another aspect the company has done is to create better working conditions and customer relationships as from 2002 Nike addressed the issues of employees exploitations and carried out random company inspections to check the working conditions of its employment. [5] Nike has training programmers to train its employees and advance them with the current market needs. Another thing that the company is involvement in is to improve its company image by getting involved in corporate social responsibilities. The company thus contributions to charities organizations and also organizes social activities for the society, and sponsors individuals and persons. This has greatly improved its image. Nike is also one of the most environmental friendly companies. And this has a very positive image in the eyes of the public which has become much environmental aware. Conclusion Nike is a big organization that commands a large market in the world. It is apparent that to maintains such a market by investing a lot in marketing and research so that it can satisfy its customers and keep up with new trends on the market. Better management skills and quality products are the main ingredient for success for any company. Many obstacles in marketing and management come up to challenge the company including stiff competition. But it is clear that with well and timely adjustments in marketing and advancement in technology and being to be innovative the company has managed to capture and maintain its markets. Therefore for any company to remain profitable and impressive its must embrace prudent management and better technology. References Collingwood, H. (1988): Nike Rushes in Where Reebok Used to Tread; Business Week, October 3, p. 42. Holmes, S. and Christine, T. (2002): How Nike Got Its Game Back; Business Week, November 4, pp. 129-31. Jenkins, H. W. (1998): The Rise and Stumble of Nike; Wall Street Journal, June 3,                [1] Jenkins, H. W. (1998): The Rise and Stumble of Nike;   Wall Street Journal, June 3, [2] Collingwood, H. (1988): Nike Rushes in Where Reebok Used to Tread; Business Week, October 3, p. 42. [3] Collingwood, H. (1988): Nike Rushes in Where Reebok Used to Tread; Business Week, October 3, p. 42. [4] Holmes, S. and Christine, T. (2002): How Nike Got Its Game Back; Business Week, November 4, pp. 129-31. [5] Collingwood, H. (1988): Nike Rushes in Where Reebok Used to Tread; Business Week, October 3, p. 42. How to cite Nike Incorporation, Essay examples

English Summary Thesis Statement

Question: Discuss about theEnglish Summaryfor Thesis Statement. Answer: Introduction The Thesis statement of the article is that while happiness seems to the ulterior goal of life for all the human beings, very few people have comprehensive knowledge about the nature and the actual source of happiness. Usually people tend to think that happiness can be found via the pursuit of materialistic things, and yet true happiness is only realized by creating memorable experiences in life. The central idea of the article is that while most of the people tend to rely on living a secure, safe and prosaic life, they fail to explore what real happiness constitutes. A person, doing a job, travelling back and forth from his office, may earn huge amount of money, but he fails to relish happiness in the true sense. However, a man who is not much interested in leading a secure job, occasionally goes around meeting friends and family, or makes plans for movies, will be far happier. While materialistic things can bring instant happiness, the happiness in itself is much transient as after some time, the man gets habituated with the materialistic objects, and fails to hold on to the same. On the other hand, a man who gains experiences by climbing a mountain, or simply visiting a new place, will undoubtedly create memories to cherish all his life. Since the happiness derived through materialistic objects seems to cease after some time, the article rightly concludes that continuous challenges, interruptions and obstacles are highly important to ensure the long-lasting impact of happiness. Another important supporting idea regarding the nature of happiness introduced here, is that the apprehension of happy moments bring greater satisfaction that the actual pursuit of the same (Dunn et al.). Thus this argument of deferred gratification also goes to prove that happiness is essentially a matter of the mind, which is best achieved when experienced rather than being begotten. Further, the role of experience in the gratification of mind has also been reinforced, as the article rightly states that an individual derives greater pleasure by helping other people, or feeding the, rather than buying food for himself (Sunstein). Now, since the article reinforces the importance of experience in bringing about happiness in life, it also states the importance of giving out money, and helping other people, instead of spending the same for self-gratification. Besides, the article also states that a person can create happiness for himself by doing new things and travelling to new places, rather than buying expensive things. Happiness implies a spiritual awakening of the mind, not a mere pursuit of materialistic objects. However, even though the central argument is indeed true in highlighting the importance of experience, it should also be noted that such arguments are challengeable. Happiness in itself is inherently a subjective concept that varies from one individual to the other, and hence even a shy man can be happy without socializing, or a man who loves to stay at home, may not wish to go out for enjoying adventures, and still stay happy. Reference List: Dunn, Elizabeth W., Lara B. Aknin, and Michael I. Norton. "Spending money on others promotes happiness."Science319.5870 (2008): 1687-1688.. Sunstein, Cass R.What You Can Learn From The New Science Of Smarter Spending. 1st ed. 2013. Print.