Biochemistry, Nanotechnology, and the Future Help (page 2)
Introduction to Biochemistry and Nanotechnology
Chemistry is life! This should be everywhere on shirts and billboards! Chemistry describes the basic building blocks of matter. Atoms, molecules, sub-atomic particles, solids, liquids, and gases make up everything we know to exist in our world.
The fact that chemistry plays a big role in our lives is good news for people interested in working in chemistry or in fields that make use of specific element interactions. There are nearly as many practical applications as fields of study. Let’s look at a few of them.
The word biochemistry describes the chemistry of living systems. Some of these were described when we talked about organic chemistry and the molecules that make up living things.
One of the ways that changes take place in organic molecules is through the life cycle of microorganisms. A single-celled organism, through its metabolism , builds up or breaks down organic molecules.
The biological molecules that make up living cells, organs, systems, and the environment can be divided into four types: proteins, carbohydrates, nucleic acids , and lipids . Most of these molecules are simple structures covalently bonded to similar molecules, but some can reach incredible sizes in molecular terms. They are called macromolecules . Figure 18.1 shows an example of a macromolecule: β -carotene (the yellow color in carrots).
Organic protein molecules serve different functions for living systems. Some offer structural strength, as in the chitin shells of crabs and bone of mammals, some provide transport, as in hemoglobin, some act as blueprints for cell and organ development (DNA), some serve as messengers (hormones) between body organs, and some speed up metabolic reactions (enzymes).
The molecular weight of proteins ranges from 6 × 10 3 to millions of atomic mass units.
Proteins are made up of small molecules that contain an amino group (−NH 2 ) and a carboxyl (−COOH) group. These molecules are called amino acids .
Most protein reactions are made up of many different combinations of amino acids reacting with water, salts, and other elements to create or enhance needed functions. Amino acids can contain a variety of non-protein ions like some of the metals (Zn 2+ , Fe 2+ , Mg 2+ ). For example, the hemoglobin molecule uses iron as a critical part of its function of transferring oxygen within living systems. Amino acids are bonded by peptide (C–N) bonds .
In 1908, a German chemist and medical researcher, Paul Ehrlich, working with aniline dyes in the staining of disease-causing microorganisms discovered that these chemical solutions could also kill the organisms without killing the patient. He shared the Nobel Prize for Medicine with Elie Metchnikoff in 1908 for his work. Two years later, Ehrlich developed the first antibacterial agent, salvarsan, to treat syphilis. Because of his interest in treating diseases with chemical cures, he became known as the father of chemotherapy .
There are many other areas where biochemistry led to important applications. In 1993, Kary Mullis received the Nobel Prize for Chemistry for the invention of a polymerase chain reaction technique for amplifying deoxyribonucleic acid (DNA). That same year, Canadian chemist Michael Smith also received the Nobel Prize for Chemistry for his technique of splicing foreign gene segments, designed to modify the production of a specific protein, into another organism’s DNA. This opened the gates to a flood of research on designer proteins and molecules produced for a specific purpose.
Designed proteins are now being used for everything from better medicines, like insulin to treat diabetes and artificial fabrics to treat and protect burn patients, to industrial foams that clump and eliminate spills from oil tankers and medicines to counteract biological poisons.
For centuries, the environment was so vast and scarcely populated that to humans it was limitless. Wood was used freely, refuse was left wherever convenient, and as long as you are upstream, you could dump whatever you wanted into the rivers and the ocean. Now due largely to better medicines and health care, people are living to their seventh, eighth, and ninth decades. Entire populations are no longer getting wiped out by disease.
Scientists began to look at humankind’s impact on this planet as the world’s population swelled to 6 billion and more. Chemists are becoming mystery investigators. The environment is a very complex mixture of elements with different concentration spikes in many areas. Industrial cities have higher levels of metals and acids in their air than rural countryside areas. Scientists must work together to combine all available information from air and water samples as well as those from industrial emissions in order to piece together the puzzle of total environmental impact. The interconnectedness of all forms of life also affects the complexity of environmental pollution.
In 1995, three chemists, Mario Molina, Sherman Rowland, and Paul Crutzen, warned world leaders of damage being done to the O 3 (ozone) layer. This natural layer of O 3 molecules, located from 9 to 30 miles up into the atmosphere, protects the Earth from cancer-causing and damaging ultraviolet radiation from the sun. They discovered that human-made compounds of nitrogen oxides and chlorofluorocarbon (CFC) gases, used as refrigerants and propellants in spray cans, reacted with atmospheric ozone and reduced it. For their work, they received the 1995 Nobel Prize for Chemistry.
In response to the ozone depletion problem, chemists began looking for replacement refrigerants that didn’t affect ozone. Substitutes were found and the environmental problem lessened.
Many of the elements used today were discovered using cutting-edge technology and equipment. Since the 1960s, many of the elements added to the Periodic Table were human-made and not found in nature. These molecules have unheard of uses that many research and applications chemists and biochemists are just beginning to understand.
Chemists working in the plastics industry came under heavy criticism when landfills became overloaded with the new, disposable containers of plastic and a softer compound called Styrofoam. Environmentalists sounded the alarm for consumers to think before they bought products, especially fast food, that came in these containers.
In order to meet the new concern, chemists doubled their interest in the biodegradability of plastic products. They found that the addition of complex carbohydrates (polysaccharides) to plastics allowed microorganisms to break down the plastic products.
Molecules that can be broken down into simpler elements by microorganisms are called biodegradable.
Carbohydrates make up a large group of organic compounds containing carbon, oxygen, and hydrogen.
Carbohydrates have the general formula of C x (H 2 O) y . There are three main groups of carbohydrates. The first are the simple sugars or monosaccharides . Some of these are the simple fruit sugars, fructose and glucose, with the formula C 6 H 12 O 6 . The simple milk sugar that many people with milk sensitivities have trouble with is lactose. The second group is known as the complex sugars or disaccharides . These are combined sugars that make up honey and table sugar, sucrose and maltose (C 12 H 22 O 11 ). Complex carbohydrates with complicated, folded structures make up the starch added to plastics, as well as cellulose of plant cell walls and rayon (processed cellulose). They have the formula (C 6 H 10 O 5 ) n where n is an extremely large number. These are commonly called macromolecules because of the number of elements and huge size compared to simple molecules. Figure 18.2 shows the structure of glucose and cellulose.
One major drawback to most of the radioactive elements discovered and produced in greater than the extremely small amounts found in nature is that they accumulate in the environment. Land, water, and air are affected by radioactive contamination. Depending on the wind or water flow, radioactive levels remain in place or are spread over a wide region. Different elements have very different decay rates .
Radioactive decay occurs when certain element isotopes are lost and there is a release of energy in the form of radiation (alpha and beta particles and gamma rays).
The three main types of radiation given off during the breakdown of radioactive elements are alpha (α) and beta (β) particles, and gamma (γ) rays. Gamma rays are high-energy electromagnetic waves like light, but with a shorter, more penetrating wavelength. Though alpha and beta particles are dangerous to living things since they penetrate cells and damage proteins, gamma rays are much more penetrating and harmful, stopped only by thick, dense metals like lead.
The waste produced in different forms of matter transformation must eventually be broken down. This is an area of ongoing concern and study for many governments who are trying to figure out how to dispose of radioactive wastes from nuclear power plants and atomic weapons. Protecting their populations from handling accidents or terrorist nuclear threats will continue to promote research in understanding the reactivity and degradation of radioactive compounds and elements.
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