Biological Molecules And Carbohydrates

Biological Molecules And Carbohydrates Quite simply, molecules are many atoms chemically bonded together. They are the most basic structural formation of an element and make up everything, from the air we breathe to ground we walk on. Some important molecules make up cells which are the most basic forms of life; every living thing is made up of cells. Cells mainly consist of water molecules but there are a number of other important biological molecules vital to allow life to exist. Macromolecules are among the most important as they can offer structural support to the cell, hold energy like a battery, act as a catalyst for biochemical reactions and store genetic information as well as having many other important functions. Macromolecules are formed of monomers – simple molecules that can bond together with others to form larger more complicated molecules. When two monomers react, they create a separate water molecule as monomers always have hydrogen and oxygen atoms in their molecular structure. A covalent bond is formed in the absence of the hydrogen and oxygen atoms, connecting the two monomers together. This is called a condensation reaction and it can continue happening until a large chain of molecules forms, eventually making a macromolecule. The reverse effect, called a hydrolysis reaction, can also occur where water will displace a covalent bond in a macromolecule reverting it back to a monomer though a catalyst is usually needed for this reaction to take place. The following image displays these reactions very well. These larger molecules are called polymers and macromolecules are biopolymers (naturally produced polymers). These consist of four types; the carbohydrates, proteins, lipids and nucleic acids with each type being made up of its own specific monomers. Carbohydrates Carbohydrates are molecules made from the elements carbon, hydrogen and oxygen. They are often called sugars and they supply a large percentage of energy to animal and human cells. The monomers of carbohydrate m acromolecules are called monosaccharides (simple sugars) with only one unit of sugar. All monosaccharides have the chemical structure (CH2O)n with n equalling 3, 4, 5, 6 or 7 depending on the number of carbon atoms the monosaccharide has – for example as glyceraldehyde has three carbon atoms the formula will be C3H6O3 and as fructose has six carbon atoms the formula will be C6H12O6. Most monosaccharides form ring shaped molecular structures when dissolved in water (see below image, depicting glucoses three forms). One of the most common monosaccharides is glucose – a vital ingredient for almost all life on earth. Plants make this monomer by using photosynthesis in the following way (CH2O represents glucose). H2O + CO2 + Sunlight and Chlorophyll = (CH2O) + O2 When these simple monosaccharide monomers such as glucose join together to form carbohydrate polymers they become disaccharides (with two sugar units), oligosaccharides (between 3 and 10 units) and polysaccharides (10 or more units also known as complex carbohydrates). The term for this joining together is called glycosidic linkages where the molecules will covalently bond by a condensation reaction (mentioned in the introductions) with each other. The disaccharide sucrose is a polymer of glucose combined with fructose, and lactose is a polymer of glucose bonded with galactose – both of these are also known as table sugar and the sweetness in milk. Cellulose, a polysaccharide, is made from many thousand conjoined glucose molecules and is the main part of plant cell walls. Another polysaccharide, starch, is again made from a large amount of glucose molecules but it is found in many food stuffs such as many vegetables, seeds, grains and fruits. Starch is very useful in that it can be stored in reserves and broken down quickly to release the energy when it’s most needed – for example a deciduous tree will need starch in the winter when it can’t carry out photosynthesi s.

Sustainable Tourism Essay Example | Topics and Well Written Essays - 2750 words

Sustainable Tourism - Essay Example In order to conduct an in-depth analysis a literature review consisting of the existing literature has been carried out. This has been followed by a primary research which would provide firsthand information about the means to ensure sustainable tourism in the nation. A questionnaire survey has been created for the purpose which would be followed by a section that would contain a set of plausible recommendations about the means to bring about sustainable tourism in a nation so as to bring about greater economic and social prosperity in the tourism industry. Introduction The twenty first century has been often cited by critics as the age of globalization which has been categorized by organizations trying to breach across geographical boundaries to reach out to new and potential market regions. This has bolstered and fuelled the economic growth of many nations whose citizens have reported considerable rise in disposable income. This has in turn enhanced the demand for leisure activitie s like tourism. Tourism has evolved in a major way with global tourism hotspots being termed as generators of revenue for the economy and the nation. According to World Tourism Organization sustainable tourism is defined as â€Å"tourism which leads to management of all resources in such a manner that social, economic and the aesthetic needs could be fulfilled while maintaining cultural integrity, essential ecological processes, and biological diversity and life support systems† (United Nations Foundations, 2002, p.1). The significance of tourism as an industry segment could be analyzed from the fact that global tourism industry contributes approximately 11 percent towards the global GDP of the world. This sector employs approximately 200 million individuals across the globe serving approximately 700 million customers across the world. Experts point out that this figure is expected to increase to exactly twice its present value. Much of the value of this global tourism comes from the developed nations which contribute approximately seventy percent of the total revenues generated from tourism. The developing nations have grown by approximately 9.5 percent since 1990 which is quite comparative as compared to the annual growth of the global tourism industry which is pegged at 4.6 percent. Tourism generates precious foreign exchange, employment as well as GDP for the nations. There are a large number of nations and islands whose economy is entirely dependent on the tourism industry (Roe & Khanya, 2001, p.1). The present study would try to analyze the aspect of sustainable tourism and would also discuss about the different factors affecting global tourism with regards to certain issues related to the environment. Literature Review Social and Economic Sustainability of Tourism The sustainability of tourism industry is largely dependent upon other sectors as many economic and social factors are said to be correlated with the tourism industry. Presence of infra structure and political stability are factors that have a deep impact on the success and growth of the tourism indus

Laziness in America Essay Example | Topics and Well Written Essays - 250 words

Laziness in America - Essay Example Now with schedules, work days running longer, various appointments, and after school activities, families are lucky if they have a frozen dinner in front of the television (the meal is not necessarily shared together). Children who once played outside for hours now have to be forced outside because they are more concerned about their cell phones, computers, and iPods. There is nothing that we could have done to prevent these changes. In a sense, it was destiny. We were bound to eventually evolve, change, and grow according to our lifestyles. The bigger this country gets, the more space we need, so houses are built bigger, cars are now SUVs, and families are having more children. Our demand for convenience have increased, bringing with it the need for fast food since we no longer have time to cook; restaurants even have drive through windows. Popularity in one-stop shopping grew, so now we can get in and out of a store, becoming more accomplished in our shopping. Computers are replaci ng not only people but many of the jobs that people once did by hand. Over the past fifty years, so much has changed. I remember the days when this technology did not exist and we seemed to manage just fine. This may cause problems for those who are becoming too dependent and relying on technology and things made ready to use with ease.