Isotopes
Isotopes are atoms of the same element with differing numbers of neutrons. This results in atoms of the same element having different molecular masses Therefore, isotopes are atoms of an element which possess the same atomic number but varying mass. As such, the recorded molecular mass of each element on the periodic table is simply a derived value based on the abundance of the varying isotopes. An example of a set of isotopes can be found when analyzing carbon atoms. There are Carbon-12 ( , Carbon-13 ( , and Carbon-14 atoms present in varying abundances in the world. Carbon-14 has been identified as a radioisotope because of its tendency to spontaneously decay into a smaller atom. In this case, Carbon-14 decays into Nitrogen-14. Carbon is a major component of living things in all of its isotopic forms. When organisms are living, they intake Carbon in its varying isotopic forms; however, upon death they stop the intake of Carbon. As Carbon-14 is present in trace amounts in the body and it decays at a defined rate the age of the dead organism can be determined. The time at which the amount of Carbon-14 is valued at half of its original amount is known as the half-life. By using the concept of the half-life, age can be determined. This process is known as Carbon dating and is used in a variety of different fields such as forensics and archeology. There are a myriad of different isotopes and consequently a myriad of radioisotopes. These radioisotopes are used in a variety of different medical roles including diagnostics and drug testing. Isotopes are present in daily life and they are now being used to improve the quality of life the human populous experiences.
Electronegativity
Electronegativity is a measure of an atom's ability to attract a shared electron when participating in covalent bonding. When one atom's electronegativity is greater than another atoms the electrons will be more attracted to the first atom. That same atom will adopt a slightly negative charge(ɗ-). The atom with the lower electronegativity will adopt a slightly positive charge(ɗ+). The bonds formed are known as "polar covalent" however if the difference in electronegativity between the atoms is greater than 1.7 the bond is then classified as "ionic". If the difference between charges is zero then the bond is simply "covalent". An example of a non-polar covalent bond is carbon tetrachloride (CCl4). Fluorine possesses the greatest electronegativity value at 4.1 however the second highest value is connected to oxygen at 3.5. Oxygen's high electronegativity allows for it to form a multitude of different molecules which are used for many biological processes. The high electronegativity that oxygen possesses also means that the bonds it forms tend to be polar in nature. Water is a polar molecule because the oxygen adopts a slightly negative charge whereas hydrogen adopts a slightly positive charge. Electronegativity decides the polarity of molecules and the characteristics that the molecule exhibits are extensions of its polarity. Therefore, electronegativity ultimately decides the role and characteristics that molecules will possess and how they will interact with other molecules. Polar molecules will dissolve polar molecules whereas non-polar molecules will dissolve non-polar molecules. This relationship is present in many different biological processes and allows for the human body to function.
Isomer
Isomers are molecules that have the same atomic mass but different atomic arrangements. The components are the same in isomers however the three dimensional shape that they adopt varies. The molecular formula for isomers is also the same. The different arrangements that the isomers adopt change the function that they perform and how they interact with their surroundings. An example of some isomers are glucose and galactose. Although they are made up of the same basic components their arrangement changes how the human body deals with them and uses them. Glucose in the body is converted to galactose by changing the arrangement of the components. From this galactose can be more easily used in processes such as breast feeding. Galactose can also be converted to glucose for use in the body as a basic energy source through conversion to ATP. The different shapes that isomers adopt allow for their form to suit their function. By specializing molecules in the body the functions that need to be accomplished for life are made more efficient.
Radioisotopes
Radioisotopes are atoms which spontaneously decay into smaller atoms while releasing subatomic particles and energy. As they decompose the energy that is released is radioactive in nature. This radioactivity can be traced, detected and used for a variety of different purposes. The most commonly used radioisotope in medicine is technetium-99. It has a half-life of only six hours which means it will be nearly non-detectable in the body within a day of initial contact. Technetium-99 is used to view different areas of the brain such as the skeleton, brain, thyroid, lunges, and many more. As the radiation that the isotope releases is traceable the movement of the radioisotope can be used to image various body parts. Technetium is very versatile however some radioisotopes are much more specialized. Iodine-131 is mainly used to identify problems with the thyroid gland including enlargement and cancer presence. Radioisotopes are also used in medical research and drug development. By including radioisotopes in new drugs their movement and area of effect can be traced. If a drug is designed to treat a problem in the heart a radioisotope can be tracked to ensure that the drug moves towards the heart. Amazingly, radioisotopes are used for more than just medical diagnostics. They are also used in biological research. Melvin Calvin was a researcher who used Carbon-14 to trace the sequence of reactions present in photosynthesis. With a wide variety of uses radioisotopes and radioactive tracers enable humans to better visualize the world around them and gain a greater understanding of complex reactions in the world they inhabit.
Polymer
Polymers are collections of mostly repeating molecules bonded together to form long complex chains. By bonding many simple molecules together more complex compounds can be developed. As the compounds become more complex their functions also become more complex. Again polymers demonstrate that form is simply reflective of the function that is being performed. Polymers in the body include lipids and proteins. Proteins are polymers which are composed of a variety of amino acids and bound by peptide bonds. The defining characteristic of proteins is the presence of nitrogen in the bonds. Proteins are used to develop many of the characteristics of human beings. Proteins are a result of the genes that code for the characteristics of individual organisms. These genes form amino acids which then bond to form proteins. These proteins are specialized polymers whose structure defines their function. An example of a polymer is albumin. It is a protein in the blood which acts as a transport for fatty-acids. Without the complexity that polymers provide the diversity of life present on the Earth would not be possible.
Oxidation-Reduction Reactions
Oxidation-reduction reactions or redox reactions are chemical reactions which result in a change in the oxidation number of an atom. The reactions work in tandem to explain the final outcome of a chemical reaction. The oxidation reaction separates the initial atom or molecule into its ion and the electrons it has lost. The reduction reaction uses the lost electrons from the oxidation reaction in tandem with the other atom or molecule to create the second ion. From there the final equation can be derived and the new compound can be defined. In the human body these reactions are used to convert the fuel and oxygen present in our bodies into water and waste. Cellular respiration uses glucose and oxygen to provide energy while releasing carbon dioxide and water as a result. The final formula appears as C6H12O6(aq) + 6 O2(g) 6 CO2(g) + 6 H2O(l). Cellular respiration using the sugars in our body and the fats stored are one example of redox reactions however photosynthesis is another example. It is simply cellular respiration in reverse and provides sugar and oxygen. Redox reactions are the basis of life. They define the processes which form the defining characteristics of flora and fauna. Cellular respiration and photosynthesis are the most important functions in the natural world. These reactions allow for life and therefore redox reactions are the most important chemical reactions in the world.
Acids
Acids are substances that increase the concentration of the hydronium ions present in water. They are sour in taste, support conductivity of electricity, and turn blue litmus paper red. There are a variety of different acids which possess these characteristics however some are more acidic than others. Hydrochloric acid is a strong or complete acid. All of the hydrogen atoms present in the acid will dissociate into the solution. This will make the solution extremely acidic. Acetic acid is a weak or partial acid. Only five percent of the hydrogen present in acetic acid will dissociate. The resultant solution will be acidic but not as drastically acidic as a hydrochloric acid solution. Acids are also classified as proton donors. Acids are responsible for changing the pH of a variety of different areas in the body and the genetic coding of individuals. The inside of the stomach is extremely acidic as the qualities associated with acids are able to kill many of the bacteria that are ingested during the digestion process. The introduction of acids are also present as a result of physical activity. Lactic acids are a by-product of physical exertion in the body. As such, the body needs to take action to eliminate the acidic environment being created. Amino acids are also an important part of biology. These acids allow for biological processes to occur. The proteins they form work to make-up the defining characteristics of different organisms and the amino acids procured from outside the body allow for healthy human development. All in all acids are a part of biology that can be both positive and negative. Their ability to change the pH of solutions can be dangerous but it can also have a positive outcome. If the blood in an individual becomes too basic the addition of carbonic acid can return the blood to a state of balance.
Bases
Bases are substances that increase the concentration of the hydroxide ions present in water. They are bitten in taste, slippery to the touch, support conductivity of electricity, and turn red litmus paper blue. Like acids there are strong bases and weak bases which will dissociate in the solution at different rates. Sodium hydroxide is considered a strong base because it ionizes completely in water whereas ammonium is considered a weak base. Ammonium ionizes only partially in water. Bases are also known as proton acceptors because they accept the protons that are released by acids. This relationship allows for bases to neutralize acids. Bases are extremely important in the development of flora however they are also present in human development. Ammonia is an important base that is used as a form of nutrients for many plants. This basic compound is broken down inside the plant and is used to develop many of its physical components. Bases are also used to counteract acidic conditions in the body. When the stomach becomes too acidic bases are added to neutralize some of the acid and return the pH in the stomach to its normal range. This concept is also true when considering the pH of the blood. When extended physical exertion is present the pH of the blood can become acidic. Carbonic acid, an acid, can be converted into a bicarbonate ion and vice versa. Some amino acids that make up the proteins in the body also occupy basic roles. They have the characteristics of bases and can sometimes act as buffers in certain circumstances. This transference between an acid and a base allows for the body to maintain the pH of the blood.
pH - Power of Hydrogen
pH is the measure of how acidic or basic a substance is. More specifically, it is the negative logarithm of the hydronium ion concentration in a solution. This relationship is demonstrated through the equation pH =-log10(10-7 mol/L) =7. On the pH scale the value of seven is neutral as the presence of hydronium and hydroxide ions are equal. Any value less than seven is considered acidic as the amount of hydronium ions is greater than the number of hydroxide ions. Similarly any number above seven is considered basic as the amount of hydroxide ions is greater than the number of hydronium ions. In the body pH plays a vital role in the functions of many different components. The pH of gastric acid in the stomach is extremely low with a range from 1.5 to 3.5. This intense acidity is used to kill bacteria and other unwelcome guests of the digestion process. When the acidity of the stomach acid becomes too strong a base is added to neutralize the acid. Neutralization reactions occur between an acid and a base and leave water and a salt as the resultants. By controlling the pH of the stomach the quality of life experienced by people can be increased. pH can also be changed in the muscles of the body. An acidic environment is created during times of physical exertion. This acid hurts the effectiveness of the muscles and creates the burning sensation associated with muscle fatigue. Through the body's ability to return the pH to a neutral state it removes the acid and consequently the pain associated with exercising. The pH of blood is also important as it is constantly fluctuating. Through the use of a buffer system the pH of the blood can be controlled through the constant transformation of components in the blood. During cellular respiration water and carbon dioxide are produced. These two components then synthesize to form carbonic acid. This acid releases hydrogen ions and bicarbonate ions which make the blood more acidic. To return the blood to a more basic state the two ions are returned to carbonic acid and eventually carbon dioxide and water. This process keeps the pH of blood consistently neutral allowing it to be efficient in its other processes. pH is important in the body because it allows for different bodily functions to occur effectively.
Buffer
Buffers are chemical systems used by living organisms to resist significant changes in pH. They contain substances which can donate hydrogen ions when they are required and contain other substances which can remove hydrogen ions when there are too many present. One of the most common buffer-systems present in the human body is the carbonic acid/bicarbonate buffer. When the bloodstream becomes acidic due to environmental effects such as an acidic meal or physical exertion there is a surplus of hydrogen ions. The buffer system in place takes these excess ions and uses them to create carbonic acid. This balances the pH of the blood and keeps the organism healthy. This process can also work in reverse as carbonic acid can decompose into hydrogen ions and bicarbonate ions. This buffer allows for the pH of blood to be controlled. Proteins can also be used as buffers. Hemoglobin, a protein found in blood can remove excess hydronium or hydroxide ions as the amino acids which formulate their composition can be both acidic and basic in nature.
