Mutual Exclusion in Multiprocessor Systems Essay

Mutual Exclusion in Multiprocessor Systems - Essay Example This issue can be resolved by employing an appropriate mutual exclusion of the programs and their resources so that no two programs would request for the same resource if one of them is using it already. Therefore, under many occasions, it is important for the programs to recognise the usage of any of the resources and should provide for resolving the same at the earliest possible opportunity. This paper aims at studying the possible mutual exclusion algorithms that are employed in a uni-processor system and in a multi-processor system. With reference to the execution of a code or a section of a code, these should not be executed by two processes at the same time. They are to be critical code. Assuming that there will be multiple processes running on multiple processors, there could be more than one process requesting for the same resource. It is important for all the requesting processes to allow one process to run at a time. Mutual exclusion algorithms should ideally provide lee-way for the following options: 1. Freedom from deadlock: Locking is the simplest way of avoiding repeat use of critical processes. While locking can be effective for stopping execution of a job, when another one is running, it might not be fool proof. For instance, if process 1 locks a critical section A for its use and it makes use of section B for execution of the section A and suppose process 2 locks section B and for its execution if it needs section A which is locked already by process 1, then a dead lock occurs. (Figure 1). Any successful mutual exclusion should also avoid deadlocking. 2. Freedom from Livelocking: This is a desirable requirement for the algorithms offering the mutual exclusion. This would ensure that there is no permanent lock existing for any process; a corollary of the deadlocking. But it also says that if some process wants to enter a critical section, one such process will enter the critical section. This implies that the one

Case Study Example | Topics and Well Written Essays - 500 words - 14

Case Study Example The government wanted to establish a knowledge-based economy and technology-oriented, efficient and well-equipped libraries were one of the main pre-requisites for building such an economy. The advance in information search technologies was rendering the old libraries defunct, thus the call to upgrade them to meet the present and emerging needs of library users. The change was massive in that there was an overhaul of the entire management style from hierarchical to team-based approach. The culture of the library was also changed. From strategic standpoint, the change was aimed at increasing the competitiveness of public libraries by making it customer-centric, which would be equated to profit maximization in for-profit organization. The Singapore library system’s â€Å"customer† is the general public, which includes students, people with small business enterprises and individuals of various ethnic backgrounds. The â€Å"product† offered by the library include books and other collections that facilitate learning and promote cultural heritage. Initially, service delivery was through queuing for services and there was a lot of inefficiency. In order to reduce the lines for services, a self-service system was implemented in which self-checkout machines were used. Unlike the traditional libraries, the change ensure that Singaporeans accessed the libraries anytime and from anywhere by making available electronic information to users, which they could remotely access. The traditional service delivery remained unchanged. This is because the aim was to use technology to improve rather than replace traditional service delivery system. The retention of the traditional service delivery system was not a change failure, but an intentional move by the NLB. The major components of the change effort included the government, the community, the management and the entire staff of public libraries. The government provided financial support required for the

Ethical Analysis Of The Video Game

Ethical Analysis Of The Video Game Our group chose the video game software development industry as our target industry to examine. We chose this industry because it has had a very interesting dynamic of financials versus ethical issues in the past. First, the institutional investor should be very interested in this industry financially for several reasons. It is a $25 billion industry as of 2011. 49% of U.S. households own a game console, with the average household owning at least one console, smartphone or PC. Eight video games are purchased per second in the United States (esa). Research into an industry leader gathered that Activision Blizzard (ATVI) has been grossly outperforming the market for the last 10 years. With healthy earnings, a substantial profit margin, a modest dividend yield, and a manageable price to earnings ratio, this stock will easily be a welcome addition to any institutional investors portfolio. However, our group suggests that ethical and social issues should also be taken into account when choosing to invest in an industry and a particular stock. Specifically, there is speculation of links between video games and violent crimes, obesity, anti-social behavior and a variety of health problems. The link to violent crimes hits especially close to home in relation to the speculative link between the 2007 Virginia Tech shooting and the video game Doom. In addition, there has been news regarding unethical treatment of development employees. All these will be scrutinized below and must be contrasted with several benefits games afford the community such as high profits and gainful employment for the business. Video games can also produce the benefits of increased attention, positive psychological conditioning, and an outlet for aggression and stress in its players. Following this analysis we will conclude as to whether an institutional investor can feel justified ethically and fina ncially in investing in the video game industry. Ethical Issues and Pressures facing the Gaming Industry The gaming industry battles several ethical dilemmas. These are moral and social choices that have to be made that may or may not conflict with achieving higher profits. These ethical issues could be subdivided into different categories. There are issues pertaining to the nature of the product or game itself, the effect this product has on the consumer engaging in the game, as well as the ethics related to game development such as workplace ethics and developer employment practices. Therefore, there are a vast amount of ethical issues and pressures facing the industry in general that could be addressed, and to cover each and every one of them would far exceed the scope of this analysis. As a result, we will only focus on those ethical issues pertaining to the industry that we believe are especially important for an institutional investor to take into account when making an investment decision for this industry. One ethical issue pertaining to the nature of the game is the ethics of representation. Many activists have criticized video games for being misrepresentative of real demographics. Games like Grand Theft Auto have been criticized for not only misrepresenting minorities as criminals, but also for promoting race violence. In addition, the University of Central Florida concluded that video games vastly misrepresent females. This study chose 33 games and found 41% to contain no females, 28% portrayed women as sex objects, 21% portrayed violence against women, and 30% misrepresented females in terms of their body as well as their positions as damsels in distress or insignificant participants (Dietz, 1998). Do video game manufacturers have a social responsibility to portray population demographics as accurately as possible? If so, does that limit their ability to make riveting gameplay? What is known from previous litigation is that the First Amendment protects gameplay development as free speech and manufacturers are free to create gameplay as their want. Another aspect of the ethics of representation is the portrayal of realism. The more realistic the gameplay the better the user experience, but can being too real be going too far? Recently, seven Navy seals were disciplined for divulging classified tactics and procedures to a Medal of Honor video game. The video game makers, Electronic Arts, state on their website that this game gives the player an authentic experience that puts the gamers in the boots of a soldier (Lerman, 2012). Being too realist can not only divulge secret information to the public, but it also could be seen as training gamers for real situations like that in the game. Examples of this are games like Grand Theft Auto made by Rockstar games. Video game activists, led by Jack Thompson, have been exerting pressure to limit the violence in games, labeling violent games as murder simulators (Jack Thompson (activist)). Violence in video games is seen to be worse than violence in movies, TV or music because games are in teractive. Each play gradually desensitizes and emotionally hardens (termed operant conditioning in psychology) the players to the graphic violence. A 2005 American Psychology Association study corroborates that by stating that there is a causal link between violent video games and teen aggression (Committee led by Elizabeth Carll, 2005). In addition, the games give players weapons training and procedural tactics to carry out maximum damage in the real or virtual world. A much publicized example is Eric Harris and Dylan Klebold, the assailants in the Columbine High School purportedly being frequent players of the id Software game Doom (Video game controversies). There is much speculation as to whether these games actually influenced and aided these brutal crimes, as there is the larger debate as to whether things such as the realism of violence, gore and sex have a causal link to mimicry of these activities in the real world. Another major ethical issue arises from the fact children are a large part of the video game consumer base. 18% of the video game population is boys under the age of 17 (esa). This statistic may not seem significant but the next few are: studies have shown that 97% of children play video games and that 50% play video games every day (Irvine, 2008). Parents have been concerned about the violence, murder, and crime that many games promote, and their effect on their children especially when they spend long hours every day engaging in these games. One large organization focused on this is MAVAV: Mothers against Videogame Addiction and Violence. If there is physical and psychological harm being done by video games, children are very much in harms way. Because of this, the Entertainment Software Review Board (ESRB) exerts pressure to regulate the exposure of certain games to people of certain ages. Apart from the adverse effects that violence, gore and sex in games can have on the players, there is a link between overplaying of games and several health issues. The physical issues are many: repetitive strain injury, skin problems, muscle stiffness, vision problems, dizziness, headaches, and so on all the way up to even death (Video game-related health problems). Some muscle and skin problems related to video games have been playfully termed PlayStation thumb, Nintendinitis, Wii fractures and so on. In addition, there is a link between video game overplaying and sleep deprivation, nausea and obesity. There is also a list of non-physical effects like addiction, anti-social behavior and increased aggression. Most of the ethical issues discussed so far are tangible to the consumers, and publicly felt because they have a somewhat direct effect on the players. However, there is very little revealed about the behind the scenes developer employment practices that take place before a game is made available to the market. Crunch Time is one of the major reasons developers employment practices and work ethics are subject to a lot of scrutiny. Crunch Time is defined as the period in a games development cycle where the developers have to shift their working patterns into the highest gear in order to ship a game on time (Xbuttonkill, 2011). This has led to developers working as long as 12 hours a day, 7 days a week. In fact, Mike Capps, President of Epic Games, said on an industry panel that he wouldnt hire someone if they werent willing to work 60 hours per week. When developers use crunch time as an employment condition, and force their employees to work long hours, their only concern is to get t he game released on time and make millions. In other words, they tend to depend on crunch time to decrease the risk of competition. They do not seem to care about the physical and mental health problems unreasonable hours have on their employees. The risks of crunch time span even beyond physical and mental health problems. Studies show that overworking affects marriages, and causes children to lose attachment to their parents, because developers get to spend less time at home (Groen, 2011). Corporate Social Responsibility in the Gaming Industry In order to combat such ethical issues and pressures, companies in the gaming industries have outlined certain Corporate Social Responsibilities (CSR) which they take upon themselves. Part of this initiative includes ensuring that the video games content is appropriate in terms of health care and promotes an educational message. Video games such as: Bully, Grand Theft Auto, Call of Duty: Modern Warfare and World of Warcraft (Blizzard Entertainment) have been scrutinized for many years for the violent and sexual content involved in the games (Leigh, 2011). Both video game developers and the government have recently been taking actions to create a social impact. Governments of many countries have also been involved in activities to control video game threats. For instance, the Chinese government has restricted the number of hours a person can play a video game. The Thailand government banned GTA 4 after a cab driver got carjacked in the similar fashion shown in the game (The Telegraph, 2008). Various countries, due to violent content, have also banned video games such as Wolfenstien, Carmageddon, and Fallout 3 (Leigh, 2011). Many companies have already done much to improve the social and environmental impact of their activities through the creation of programs to tackle the issues of game content. These companies also create games to promote education and participate in events to encourage social awareness and development. Blizzard Entertainment, producers of one of the most famous video games, World of Warcraft, has introduced a function known as Parental Control, which allows parents to control the hours played by their children. Many other games including World of Warcraft have also been promoting Screen-warning messages to control the excessive use of gaming and promote the effects of gaming on health. Some of the World of Warcrafts screen messages were: Take everything in moderation (even World of Warcraft) and Bring your friends to Azeroth, but dont forget to go outside of Azeroth with them as well (Martinez). Games for Change (G4C) is a non-profit organization that has been promoting education and valuable messages through its video games. According to the company, video games are one of the most innovative and powerful learning tools for people any age in 21st century. According to the Mr. Asi Burak, Co-President of Games for Change, video game developers should not consider the quantity of the games sold but should consider the behavioral change that the game could provide (Rowley, 2011). The Entertainment Software Association (ESA), which is exclusively dedicated to serve the business and public affair needs of video game producers, took another CSR initiative recently in the gaming industry. ESA introduced the Entertainment Software Rating Board (ESRB) that assigns rating to the video games so that the parents and buyers can make an appropriate and informed decision. The rating gets divided into three categories: A.) rating categories, which suggest the age appropriateness and divides games into categories of Early Childhood, Everyone 10+, Mature etc. B.) Content descriptor, which reveals the content that may have triggered the rating or may be the interest or concern for the parent such as crude humor, alcohol reference, blood, nudity, intense violence etc. And C.) Interactive elements tell the user about the interactive aspect of the product like explaining the games ability to share your personal information, location and ability to interact with others (ESRB). Some organizations help gaming companies get involved with Corporate Social Responsibility through charity. Gamers Outreach Foundation is one such charitable organization that uses interactive entertainment through video games to help others. The company focuses on three initiatives: Project Go Cart, Fun for Our Troops and Gaming for Others. With these initiatives the company collects donations that are eventually used to provide entertainment in the form of video games to people such as U.S Troops and patients in hospitals (Gamers Outreach). The above is just the tip of the iceberg in the endeavor that several firms and organizations of the gaming industry have done to improve its social and environmental impact of its activities. Some firms have done more than others. Rockstar Games, which produces Grand Theft Auto, in our opinion, does not live up to the efforts of other companies. As mentioned above, even though some governments have banned GTA 4, the company is launching GTA 5, with similar if not more violent and sexual content. Regardless of some firms disregard for social responsibility, there are companies which, in our opinion, have made an unprecedented effort to improve the impact of its activities and increase social awareness. One of these companies is Sony Computer Entertainment Inc. (SCE) who has done much to improve the social and environmental impact of their activities. Throughout numerous countries and various initiatives, SCE carries on activities to encourage a strong, healthy and productive social environment. In Japan, they have set up company visits where students can visit the headquarters as part of an integrated studies system and career education. Along with gaming classes held in schools with the objective of providing media literacy to students, SCE supports several schools in their e-learning approaches. One such program uses PSPs in classes in order to support individualized learning and motivation for scholastic proficiency. In North America, SCE provides joy to families in need a s part of their ongoing Holiday Giving program. They host an annual Nite to Unite (NtU) benefit dinner, which is an unparalleled effort by the interactive entertainment community to make a difference in the lives of Americas kids. NtU is an auction supported by members of the association and the interactive entertainment industry, raising funds for the ESA Foundation. SCE employees participate devotedly in such charities along with other community programs and partnerships for the independence and development of disadvantaged children. Since 2007 they have expanded their PSP in Education Program where PSP has been used extensively at more than 400 educational and training institutions in the UK, as its exceptional ability to capture and play educational digital content has made it a gripping new mobile learning program. In Asia, the SCE also actively participates in innumerable charities working to increase education and provide media literacy to students, reducing the gaming indust ries carbon footprint, and achieving basic goals of ending poverty and hunger in society. Leading by example, SCE offers job opportunities to low-income workers during the annual Asia Game Show; it also has a game console-recycling program in various shopping centers (Sony Computer Entertainment Inc.). Virginia Techs Investment Strategy Before we even look at whether Virginia Tech should invest in the gaming industry, we need to look at how Virginia Tech invests when it comes to social and ethical issues. First, we need to look at whether Virginia Tech should take corporate social responsibility (CSR) and ethical issues pertaining to industries into account in its investment decisions. We also need to see if these reasons for taking CSR and ethical issues into account are purely financial or ethical. We believe that Virginia Tech should definitely take CSR and ethical issues into account when investing in industries. The reasons for this are both financial and ethical. The ethical reason for whether or not Virginia Tech should invest in specific industries has to do with core values. According to their core values, Virginia Tech promotes personal and institutional integrity: integrity demands that all members of the universityà ¢Ã¢â€š ¬Ã‚ ¦engage in continual civil discourse and ethical behaviorsà ¢Ã¢â€š ¬Ã‚ ¦inte grity demands maintaining standards of personal and professional behavior of the highest order (Virginia Tech). If Virginia Tech promotes integrity among all members of the university and wants them to engage in ethical behaviors, they should want to invest in industries which promote similar values as well as engage in ethical behaviors themselves. The financial reason for whether or not Virginia Tech should invest in specific industries has to do with examples from the past. We have seen companies such as WorldCom (2002), Tyco (2002), Enron (2001) and Madoff Securities (2008) crash due to poor ethical standards. Even though all four of these examples would have been excellent financial investments before they crashed, that did not stop everyone who invested in these companies to lose almost all of their securities. If people researched the CSR and ethical cultures of these companies before they invested, they could have possibly avoided a poor investment. The point is that we believe that ethics and financial success cannot be separated from each other. This is why we believe that it would absolutely be appropriate for Virginia Tech to sacrifice some expected financial return for ethical reasons. The reasons for this have mostly been covered already. First, Virginia Tech needs to be corporately responsible even if others are not. It is in Virginia Techs core values to hold themselves to high standards especially when it comes to integrity. If Virginia Tech does not act according to its core values, it should not be looking at investing in the first place. Second, we believe that good ethics will result in long-term success. If Virginia Tech wants short term returns, it could invest in companies such as WorldCom, Tyco, Enron or Madoff Securities: companies which get high returns at the cost of ethical standards. However, if they are focused on long-term financial success, they would see that those firms who have solid ethical standards will obviously be the better choice. Lastly, we need to look at whether or not Virginia Tech should invest in other industries or businesses for reasons other than maximizing financial return. We believe that there are multiple reasons to invest in industries or businesses other than financial return. One reason is to increase jobs in your home county/region/state. Virginia Tech, being a public institution of Virginia, should want to improve their home states economic state by investing in Virginia businesses to increase jobs. Virginia Tech should also want to invest in their alumni. If there was a business that had an alumni running or working for it and another business which would have a slightly higher financial return, Virginia Tech should invest in the first firm to portray kindness to their alumni. Lastly, Virginia Tech should invest in industries or businesses to create goodwill. The financial gain from goodwill can hardly be measured since it can lead to inside tracks for other deals as well as near infinite go od press. These are only three reasons for Virginia Tech to invest in other industries or businesses, there are likely many more. In all examples, it is important to remember that financial considerations need to be made as we need to make a profit in everything we do. However, the main thing to realize is that there are other considerations that need to be taken into account including corporate social responsibility, ethical issues and alternate investment purposes. Should Virginia Tech Invest in the Gaming Industry? According to the aforementioned reasons, and based on our gaming industry analysis and the ethical and CSR issues facing it, it is evident that an investment decision in the gaming industry by Virginia Tech is not as clear-cut and unambiguous as it seems. In other words, there are several conflicting factors that need to be taken into consideration prior to making such a major decision. These include but are not limited to ethical and financial issues, and whether these match with the institutions social and ethical investment policy. If Virginia Tech only desires to consider the ethical issues pertaining to the gaming industry, there will be a lot of strong reasons to support its decision not to invest in the industry due to a clear contradiction with its core values and virtues. Based on our ethical analysis for the gaming industry, we have seen how developers portray a lot of violence and racism through their games, not to mention the portrayal of realism, and the effect this has on the children and adults engaging in the game. The health problems that consumers suffer resulting from addiction and the long hours spent playing these games is also a serious issue that can never be taken for granted. Last but not least, we can never understate the unethical employment practices deployed by most developers, forcing their employees to work unreasonable hours of crunch time for the mere sake of making money and increasing the companys profits. Apart from the ethical issues, there are other reasons why Virginia Tech might not consider investing in the gaming industry. We believe that Virginia Techs investment policy should include investing in an industry that would increase employment in its home state. And since Virginia is not a state where the gaming industry has a stronghold, such an investment will not directly create a positive effect on employment and job creation in the state. In addition, there are not many alumni involved in this industry for Virginia Tech to support through its investment. Many organizations have shown significant effort in promoting corporate social responsibility and goodwill within the gaming industry. Gamers Outreach Foundation and Games for change (G4C) are two examples of gamers working for the greater good. However these organizations are usually non-profit third parties that do not relate specifically to the gaming industry. In addition, a publicity test might further support Virginia Techs decision not to invest in the gaming industry. The institution might be heavily criticized for becoming a major stakeholder in an industry that was suggested to blame for the tragic massacre that took place on its campus five years ago by a video game fanatic. While there might be some evidence that the Virginia Tech shooter was actually influenced by video games, we believe that if Virginia Tech invests in certain firms in the gaming industry, the institution will be making a stance against ethically inept video game companies. Since such an investment should not be in the industry as whole, we would suggest limiting the investment to those firms within the gaming industry that have proven to be more socially responsible than others. For example, unlike most game developers, Sony Computer Entertainment Inc. (SCE) is an ethically strong and socially responsible firm that has used its products and activities to promote a productive and healthy social environment. Realtime Associates is another videogame developer that has exercised its corporate social responsibility through producing serious games. They have also worked with Hope Lab, a non-profit organization, to develop and produce games that improve the health and quality of life of young people with chronic illness (Hope Lab). These included the videogame Re-Mission, which was specifically targeted to young adults and children with cancer. As a result, investing in the gaming industry through socially responsible firms like Sony and Realtime Associates will not only guarantee a high financial return on investment, but will also meet the objectives of the institutions investment policy and core values. Conclusion Although the ethical issues and pressures facing the gaming industry might not at first seem to be in line with Virginia Techs investment policy, we believe there is a considerable investment opportunity for an institution like Virginia Tech in this industry. However, we do not consider that such an investment should be made in just any firms inside the gaming industry. From our research we have found that the industry is quite diverse and there are several firms pioneering strong ethics and social responsibility in this industry. In our opinion, Virginia Tech should favor these firms with a proven track record of high ethical standards and social responsibility.

The Role of Women in Antigone :: Literary Analysis, Sophocles

One of the conflicts in Antigone, is the struggle between men and women. Ismene tells Antigone that since birth, women â€Å"were not born to contend with men,† (75) displaying women’s obedience and passivity. In the same passage, Ismene says: â€Å"we’re underlings, ruled by stronger hands,† (76) a representation of men’s aggressive and â€Å"stronger hands† that dominate women and treats them as second-class citizens. The only woman in Thebes who desires to break free from these chains is Antigone, who stands up against Ismene’s passivity urging her to â€Å"submit to this,† (77) and defy Creon by burying Polynices. By breaking Creon’s edict, Antigone challenges the traditional gender roles women and men play. In what ways does the theme of gender in Antigone, demonstrate the passion and choices behind Antigone and Ismene’s decisions? Ismene believes that women are â€Å"underlings† (76) and not â€Å"contend[ing] with men† (76) because she knows that men will always control society. This viewpoint of men’s domination of women depicts Ismene to be submissive to males while being fearful of men’s authority. Ismene is unable to have control over her destiny and decisions because she is fearful of men’s power over women, which leads to her refusing to bury Polynices. Later in the play, Ismene questions Creon’s judgment by saying â€Å"you’d kill your own son’s bride?† (641) which indicates that she is now aware that woman should have a voice and power in society. Her new understanding of Antigone’s message gives her the strength to query Creon, while additionally highlighting his cruelty. Ismene’s original belief of â€Å"submit[ing] to this† (77) and being a proper Greek girl, eventually transforms into becoming an advocate for An tigone. Her transformation defies men’s authority, the opposite of what she used to believe in. Antigone believes that a woman should be intrepid and strong, even at the risk of challenging men’s authority. When she proposes to bury Polynices, Ismene answers, â€Å"we’re not born to contend with men†. (75) Antigone’s response, â€Å"that death will be a glory† (86), does not directly address gender issues, but it expresses her fury at Ismene’s passivity. After the burial of Polynices, Antigone defiantly states, â€Å"I did it. I don’t deny a thing,† while being interrogated by Creon (492) and later comments that she was â€Å"not ashamed for a moment, not to honor my brother†. (572-3) Antigone’s gallant speech and defiance toward traditional gender identities audaciously shows her revolutionary desire for gender equality.

Newspaper vs. Magazines

Which is the most helpful source of information do people rely on? As two major kinds of mass media, newspaper and magazine played a major role in people’s daily life. Although, they belong to the same group, they also have different characteristics regarding three major factors which are style, content and appearance. Style plays a major role between these two. While newspaper â€Å"focuses on what is needed: fixed and straight to the point†, magazine tends to be more â€Å"freestyle†. Moreover, newspaper has limits whereas magazine has more room and personalized flow of information. Content is another factor that has its most important job to do within these two. In a newspaper, people can find more information than magazine. It focuses on catchy headlines in an attempt to capture the readers’ entire attention to read the entire story. It is based mostly on facts that are new and written as it happens and where it happens. Surprisingly, newspaper can easily put various topics together whereas the magazine cannot. In other words, a magazine for golfing cannot have content that is mainly of fashion and beauty tips. Therefore, the value of each is different. Another major factor within these two should be their appearance. Clearly, people can come to realize that both magazine and newspaper are published at regular intervals. As the newspaper published faster, it comes out at least once a week and daily newspaper is published daily. On the other hand, magazine are published and sorted by weekly, monthly, on bimonthly. The point being is that while newspaper is as good as one day use, the magazine can be used or read anytime. So, whichever people choose they should remember that newspaper and magazine belong to the same group despite of their differences or their characteristics, they have always played an important role in peoples’ public life all the time.

Living Environment Essay

* All living things must maintain homeostasis in order to stay alive. * Homeostasis: A balanced state in an organism’s body. * Failure to maintain homeostasis results in disease or death. * Homeostasis is often maintained using feedback mechanisms. * Feedback mechanisms are cycles in which the product of one reaction causes another to start or stop. * While organisms are balanced, they are not unchanging. The term used to describe the balanced state is dynamic equilibrium. * Dynamic Equilibrium: A balanced state created by many small, opposing changes. * Life Processes: All living things carry out the same basic chemical processes. Taken together, these processes make up an organism’s metabolism. * Metabolism: All the chemical processes that take place in an organism. * Nutrition: Using nutrients for growth, synthesis, repair and energy. * Respiration: Converts energy in food into a  usable form (ATP). * Synthesis: Making complex chemicals from simple substances. * Transport: Absorbing and distributing materials throughout the body. * Regulation: The control and coordination of life processes. * Excretion: Removing of wastes produced by metabolic activities. * Reproduction: Passes on genes to offspring. * Inorganic Chemicals: Simple compounds * Water ( H2O) : Most common substance in all living things (about 60% of body mass) * Needed for chemical reactions ( which won’t happen in â€Å"dry† conditions) * Dissolves other molecules into solution, allowing them to be transported through the body. * Oxygen (O2): Needed by most (not all) organisms for cellular respiration. * Released by plants and algae as a waste product of photosynthesis. * Aerobic respiration: Process that uses oxygen to extract energy from glucose (sugar). Used by most organisms. * Anaerobic respiration: Process that extracts energy from glucose without using oxygen. Gives less energy, so only used by some simple organisms (some bacteria, yeast). These organisms do not need to breathe in oxygen. * Carbon Dioxide (CO2): * With water, used by plants to make glucose (photosynthesis). * Waste product of aerobic respiration. * Nitrogen (N2): * Most common gas in air (70%) * Needed to make protein. * Converted into nitrates by soil bacteria. Nitrates are absorbed by plants and then eaten by animals . * Excreted as waste in urine. * Acids and Bases: * Measured by the pH scale * pH can affect rates of chemical reactions; for example, digestive enzymes work fastest in acidic environments, which is why we make stomach acid (hydrochloric acid, or HCl). * Organic Compounds: Larger, more complex chemicals. Always contain the elements carbon (C) and hydrogen (H). Synthesized from simpler substances (building blocks). * Carbohydrates: Sugars and starches * Building blocks: Simple sugars * Functions: * A starch (A) is broken down by an enzyme (B) into two simple sugars (C, D). This is also a good example of the lock and key model. A starch (A) is broken down by an enzyme (B) into two simple sugars (C, D). This is also a good example of the lock and key model. Provides energy * Stores energy in plants (starch) * Lipids: Fats, oils and waxes * Functions: * Stores energy (animal fat) * Insulation * Water proofing * Cell membrane * Proteins: Complex compounds that carry out all the body’s activities. * Building blocks: Amino acids  * Have many different functions as determined by their shape. * Lock and Key Model: Proteins must have the right shape to â€Å"fit† with other molecules. * Changing the shape of a protein will change what it can interact with its function. * Important types of proteins: * Hormones and neurotransmitters – carry messages through the body. * Cell receptors – in cell membrane; receive hormones and neurotransmitters. * Antibodies – attack foreign pathogens * Enzymes- act as catalysts, controlling all chemical reactions in the body. * High temperatures will cause enzymes to denature (lose their shape) and stop functioning. This is why high fevers are dangerous. * Nucleic Acids (DNA and RNA): Make up genes and chromosomes. * Building blocks: Nucleotides; molecular bases (ATCGU) Topic Two: The Cell I. Definition: The basic unit of structure and function in all living things. II. Cell Theory has three parts: 1. All living things are made of one or more cells. * Unicellular – single celled organisms (amoeba, paramecium) * Multicellular – have more than 1 cell; may be only a few cells, or many trillions of cells. Almost all structures in multicelled organisms are made of or by cells. 2. Cells carry out all life processes. * Everything you do is the result of the work of your cells – walking, talking, even thinking and feeling. When you get sick, it is because your cells are not working correctly. 3. All cells come from preexisting cells. This seems obvious now, but at one time people believed in spontaneous generation, the idea that living things regularly emerged from nonliving things. A) Exceptions to the Cell Theory 4. Viruses are not made of cells. However, they also do not carry out all life processes; so many biologists do not consider them true living things. 5. The first cell obviously could not come from another cell. III. Organization B) Atoms C) Molecules D) Organelles – Cell structures E) Cells F) Tissues – Cells with the same structure and function. G) Organs – Made of different tissues working together for the same function. H) Organ Systems – Groups of organs that work together. I) Organism IV. Cell Organelles: These are the tiny cell parts that make up a cell. 6. Nucleus * Controls the cell * Contains hereditary material (chromosomes, genes, DNA) 7. Cytoplasm (technically not an organelle) * Fluid/liquid in the cell – mostly water * Helps transport material 8. Mitochondrion * Carries out cellular respiration. * Gives cell energy (Powerhouse of the cell). 9. Ribosome * Makes proteins from amino acids. 10. Vacuole * Stores food, water and waste * Food vacuoles may digest large molecules. * Waste vacuoles may excrete waste out the cell membrane 11. Chloroplast * Carries out photosynthesis * Plant and algae cells only 12. Cell Wall * Gives shape, structure and protection. * NEVER found in animal cells. 13. Cell Membrane * Separates cell interior from environment * Controls what enters and leaves the cell using transport proteins. * Has receptor molecules that pick up signals from other cells. * Has antigens which are protein â€Å"tags† that identify the cell (see immune system). Topic Three: Nutrition, Photosynthesis and Respiration Reminder: All life processes are chemical activities which make up your metabolism. * Nutrition: Taking in nutrients (food) for various activities including: * growth * healing * synthesis * respiration (energy) A) Ingestion: To take nutrients into the body. B) Digestion: To break down nutrients into smaller pieces. 1. Nutrients must be broken down into smaller parts so that they can be absorbed into the blood and cells of organisms. * Starches are digested into simple sugars. * Proteins are digested into amino acids. C) Autotrophic Nutrition: Organisms take inorganic materials (CO2, H2O) and convert them into organic nutrients (carbohydrates). 2. Auto = self ; troph = food; so Autotroph = self feeding 3. Photosynthesis is most common form of autotrophic nutrition 4. Plants, algae and blue-green bacteria (cyanobacteria) are common autotrophs. D) Heterotrophic Nutrition: Organisms must consume nutrients from other organisms. 5. Hetero = other so Heterotroph = feeds on others. 6. All animals and fungi are heterotrophs. 7. Includes: * Carnivores: eats mostly animals * Herbivores: eats mostly plants or algae * Omnivores: eats both plants and animals * Decomposers: breaks down dead matter and waste * Decomposers are important for recycling nutrients * I. Photosynthesis: Process in which sun’s energy is trapped in the chemical bonds of sugar. E) Requires sunlight, water and CO2. F) Makes glucose (C6H12O6) as food. G) Water and oxygen are waste products. H) Benefits: 8. Provides food for all plants, animals and other organisms. 9. Provides oxygen to breathe. 10. Removes CO2 from atmosphere. I) Plant adaptations: 11. Chloroplast: Cell organelle that does photosynthesis 12. Gas exchange: * Stomata : Pores under a leaf; let gases in and out * Guard cells: open and close stomata to prevent dehydration 13. Transport: * Xylem and Phloem: â€Å"tubes† transport food and water throughout the plant. Two different views of the stomates and their guard cells (X). Two different views of the stomates and their guard cells (X). II. Cellular Respiration: Process that takes energy from sugar molecules and places it in molecules of ATP. J) ATP is the molecule all life uses for energy. * No organism can get energy from sunlight or sugar without first putting the energy into ATP. K) Requires oxygen, glucose and water. L) Carbon dioxide and water are waste products. M) Most organisms carry out aerobic respiration (uses oxygen) in their mitochondria. N) Anaerobic respiration does not require oxygen, but gives less ATP (energy) for each molecule of sugar. * When exercise causes human muscles to run out of oxygen, their cells will do anaerobic respiration. The waste product, lactic acid, causes muscles to â€Å" burn† so that you will stop. O) Photosynthesis and Cellular Respiration are opposite reactions! They are also important in cycling oxygen, carbon, hydrogen and water through the environment P) Common mistakes: * â€Å"Plants use photosynthesis, animals use respiration.† All organisms, including plants, use respiration to get their energy. * â€Å"Respiration is breathing.† Breathing is not respiration. Breathing exchanges the gases needed for respiration. Inhaling and exhaling does not give you ATP. * â€Å"Oxygen is used to breathe.† This is backwards. Breathing is used to get oxygen which is used for respiration. Without oxygen, you have no respiration, no ATP, and no energy. * â€Å"All living things need oxygen/need to breathe.† Anaerobic organisms do not need oxygen, and do not have to breathe.