Plasma Membrane: Structure and Function

Plasma Membrane: Structure and Function BENJAMIN  NHANDARA Explain the structure and function of the cell and the plasma membrane to include the division of labour and explanation of transport across the plasma membrane. All living things are made up of small blocks known as cells. These cells play a big role in the existence of all living things even though we cannot see the cells with our naked eyes. After we have a good look at the functions of a cell and all the organelles found in them we will have an understanding on the big role played by these minute organelles. Small blocks known as cells make up all living things. The cells that we will be looking at today are the eukaryotic cells. In the eukaryotic cells are tiny cellular structures known as organelles that perform unique specific functions in order to keep the cell alive. To help us better understand and explain what really happens in a cell we can look at a country like the UK. In the UK they are different government departments, organisations and sectors that work together for the good of the country. UK in this case may be likened to a cell and the organisations, departments, sectors will represent the organelles. In order to separate the inside of a cell from its environment the cell is surrounded by a membrane that acts as a protector for the organelles. All membranes are permeable to regulate the transport of materials in and out of the cell through small pore (Sue Hocking,2008). The largest organelle in the cell is called the nucleus and it is surrounded by a nuclear envelope which is a double layered structure made of two adjacent membranes. The envelope has pores which enable communication between the nucleus and the cytoplasm. The nucleus is the control centre of a cell where all instructions are passed on to other organelles. Just like the parliament of the UK we could agree that it also has a similar duty to pass all legislation of the land and assess all laws to ensure a good and safe life for its citizen. The nucleus contains coded genetic information in the form of DNA molecules which are involved in the synthesis of proteins (Ann Fullick et al.,2015). The DNA detects what the cell is going to do and how it will do it. Inside the nucleus is a dense ,spherical structure known as the nucleolus which is responsible for the production of ribosomes. The nucleolus is like a factory. Ribosomes according to Gareth Williams (2000),are tiny organelles that are found in large numbers in a cell. They have a diameter of about 20nm. They attach themselves to the endoplasmic reticulum (ER) after leaving the nucleus and this is known as the rough endoplasmic reticulum(RER). There is another type of endoplasmic reticulum without ribosomes known as smooth endoplasmic reticulum, the other ribosomes float freely in the jelly like fluid known as cytoplasm. Enzymes are synthesised in the cytoplasm by the ribosomes. While the main function of the endoplasmic reticulum is producing and packaging proteins. Smooth endoplasmic reticulum produces lipids and steroids. The synthesis of a protein shows the division of labour in a cell.   Ã‚   We also have some organelles that were first observed by the Italian scientist Camillo Golgi. These organelles are known as golgi, they appear as stacks of flattened sacs. Assembling glycoproteins such as mucin by combining protein and carbohydrates. The golgi also produces digestive enzymes and the formation of lysosomes. Lysosomes are spherical sacs surrounded by a single membrane and they contain some powerful digestive enzymes that help in breaking down materials(Micheal Kent 2000). Organelles in a Eukaryotic cell Fig 1 (www.enhantedlearning.com) As evident in fig 1,we also have the mitochondria organelles which are important in the synthesis of energy in the form of ATP by a process called Respiration. This energy is made available to the cell in molecular structure. Active cells will normally have a lot of mitochondria available. C J Clegg(2000) says the mitochondria are relatively large organelles and has a double membrane, the inner forms many folds called cristae. Entry and exit of all materials is controlled by the outer membrane , as the movement of people is also controlled by the boarders that are in place. Cell membrane are present in all cells and they facilitate the movement of substances into and out of the cell. It also goes on to provide protection for the cell. According to Ann Fullick(2000) all cell membranes are made up of two main molecules which are the lipids and proteins. These molecules react differently as the head is hyrophilic(water loving) while the tail is hydrophobic (water-hating). Cell membranes are selectively permeable meaning they let in some molecules and keep others out Below is a diagram of a phosopholipid bilayer in Fig 2 AN IMAGE OF A PHOSOPHOLIPID BILAYER Fig 2(The Science of Biology,2007) C J Clegg (2000) says materials that go through the membrane will use the basic types of cellular transport which are available which are passive transportation(no energy needed) and active transport(energy needed). In passive transport we have diffusion(movement of particles from a region of high concentration to a region of low concentration),facilitated diffusion is also movement of particles from high to low area of concentration but this type of diffusion uses a transport protein. Osmosis also falls under the passive transport(special type of diffusion involving water molecules). In this type of transport the cell does not need energy. The second type of transport is called active transport(cell needs energy ). In active transport energy is needed as the molecules will be moving from an area of low concentration to an area high concentration. Endocytosis is the movement of large particles or fluids through the membrane into the cytoplasm of a cell(Bill Indge,2000). Exocytosis is the movement of particles from inside the cell. Finally we have protein pumps that are integral membrane protein that are capable of transporting protons across membranes. The cell plays an important role in all living things despite the fact that it is so small and also we have seen that the cell has many organelles which are present to carry out different and unique functions in order to keep the cell alive. Without cells there is no life. SECTION 2 1a) The cell is a eukaryote because the cell has a nucleus that contains DNA. b) Magnification = Image size Image size = 81mm x 1000 = 81 000 µm Actual size Magnification = 4 500 Image = 18mm x 1000 = 18 000 µm Actual = 4 µm Actual Image = 81 000 M = 18 000 4 500 4 = 4 500 = 18  µm The actual width of the cell is = 18 µm c) Magnification = Image size Actual size Image size = 81mm x 1000 = 81 000 µm Actual size = 4 µm 2. Magnification = Image size Image size = 81mm x 1000 = 81 000 µm Actual size Actual size = 20 µm Magnification = 81 000 20 = 4 500 Actual size for structure c = Image size Magnification Image size = 15mm x 1000 = 15 000 µm Actual size = 15 000 Magnification 4 050 = 3,7 µm REFERENCES Ann Fullick, (2000) Heinemann Advanced Science, Biology. 2nd ed, Oxon:Heinemann Educational. Ann Fullick, Paul Bircher, and Jo Locke. (2015) A Level Biology For OCR, London: Oxford University Press C J Clegg and D G Mackean, (2000) Advanced Biology Principles and Applictions 2nd ed, London : John Murray C J Clegg, (2000) Introduction To Advanced Biology. London: John Murray Gareth Williams, (2000) Advanced Biology For You, London: Stanley Thornes Sue Hocking, Pete Kennedy, Frank Sochacki.(2008) OCR Biology, Essex: OCR Heinemann

Ethical Practices of Computer and Internet Technology

Computer and Internet technology use In the workplace gives rise to questionable ethical practices among employees as well as managers. For the last three (plus) decades the increasing availability and advances in technology has improved productivity; however the use of computers and Internet in the workplace leads to temptation to misuse the resource for personal gain.Employees and managers accessing private employee information for personal gain, improper data access to hose who are not privy to it and software copying were a few of the concerns discussed in the 30 year old article Computer Ethics: Questions Arise on Misuse in Business (Pollack, 1983). The social media boom of the last decade has brought with It additional questionable ethical violations In the workplace. Time stealing Is discussed in the New York Times online article Opting to Blow the Whistle or Choosing to Walk Away (Tugged, 2013).It states, â€Å"According to the Ethics Resource Center, a nonprofit research or ganization, the No. Misconduct observed ? by a third of 4,800 respondents ? was misuse of company time† (Tugged, 2013 Para. 4). Eric Swenson discusses the stealing of time through excessive personal use of Internet streaming and social media in his video Business Ethics & Stealing Time, by Eric Swenson, Demand Media Video (Swenson, n. D. ). In the words of Eric Swenson, misuse of company time Is time stealing. According to a study conducted by Eric Swenson, â€Å"The average employee in a white collar business spends 3. Hours daily on personal internet usage† (Swenson, n. D. ) However, he broaches the question does this matter? He calls the workers of the present and future, 2020 to be exact, â€Å"millennial employees who want to be connected and be Involved socially' (Swenson, n. D. ) Swenson states that employees now want to be online streaming videos, media, and music. Is this the way people work today? The consideration he gives is that he is more concerned about the productivity of the employee versus the exact method or use of time that it takes to get the work accomplished.My conclusion Is there Is definitely an ethical line to be drawn in personal use of computers and Internet technology within the work place. I would ascertain that if privacy is violated for personal gain or technology or work product is stolen as stated in the first article, it is most definitely ethical violation. As far time stealing, where the line gets fuzzier, It should be Judged on whether the time spent on Internet or social media has any impact on the productivity of the employee or benefit to their specific job.

Want to Know More About Medical School Personal Essay Samples?

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In Refutation To Locke’S State Of Nature Argument, We Can

In refutation to Locke’s state of nature argument, we can look towards Hobbes, Rousseau, and Mill to provide us with insightful objections. It can be claimed that first society should not have the right to self-determination but instead the right to self preserve, that property rights are social institutions and not inherent natural rights, and finally that not everyone in society is guaranteed property rights. Firstly, Locke believed in a system of justice that was based on freedom, self-governing, and the ideology that all people are naturally good. Hobbes would explain that Locke’s arguments are inherently flawed in that he doesn’t recognize that we are constantly in a state of war. This natural state of humanity or state of war is†¦show more content†¦Democracy can and never will be the answer for our society, because we would never be able to restrain the violence of human nature, ultimately leading to death and war. The only way we can peacefully preserve ourselves is to erect a common power and give our rights over to someone who can take action on behalf of the whole. This individual would be the sovereign and would govern as the unification of our rights and desires. The sovereign would have no obligations to the subject, but must uphold the subject’s rights. Hobbes states in the Leviathan selection 3, â€Å"The obligation of subjects to the sovereign , is understood to last as long, and no longer, than the power lasteth, by which he is able to protect them† (Hobbes, 147). If the rights of the people are violated, the sovereign’s power would become invalid. If we were to give up our right to self-governance, along with everyone else, and sign the social contract, we would be able to achieve a better and more prosperous freedom than Locke under his state of nature. Next, under Locke’s state of nature, he also places a heavy emphasis on extensive rights, including property rights. He believed that self-determination implied private property rights and that human life without property is not free. In refutation to thisShow MoreRelated John Locke’s Views on Property and Liberty, as Outlined in His Second Treatise of Government4596 Words   |  19 PagesJohn Locke’s Views on Property and Liberty, as Outlined in His Second Treatise of Government John Locke’s views on property and liberty, as outlined in his Second Treatise of Government (1690), have had varying interpretations and treatments by subsequent generations of authors. At one extreme, Locke has been claimed as one of the early originators of Western liberalism, who had sought to lay the foundations for civil government, based on universal consent and the natural rights of individuals