Multiple Choice: Choose the best answer from the choices given in each question:
1. Which of the following is chemistry?
a. study of matter and its composition
b. study of energy
c. study of insects
d. none of the above
2. The smallest particle of matter?
d. none of the above
3. Linkage of atoms?
a. Periodic Table
b. Chemical Bond
c. Ionization Energy
d. none of the above
4. Anything that occupies space and has mass?
d. none of the above
5. Capacity to do work?
d. none of the above
Through the ages, man has learned many things about himself and his environment. However, it was not until he was able to record his discoveries and observations that modern science began. Early scientists started organizing and classifying their discoveries and observations. From this, evolved the fundamental sciences of today. Discoveries propose new avenues of investigations, thus expanding scientific knowledge at an ever-increasing rate. Chemistry developed as a science. Chemistry has been defined as the science which deals with the study of the composition, structure , properties and reactions of matter. Today it has become increasingly evident that chemistry holds the key to life sciences.
Major Branches of Chemistry
The main major branches of chemistry are organic chemistry, inorganic chemistry, analytical chemistry, physical chemistry and biochemistry.
Inorganic Chemistry is the study of compounds that do not contain carbon.
Organic Chemistry is the study of compounds that contain carbon .
Physical Chemistry is the study of heat, electricity, and other forms of energy in chemical processes.
Analytical Chemistry - the study of the chemistry of matter and the development of tools used to measure properties of matter.
Biochemistry - the study of chemical processes that occur inside of living organisms.
The interrelationships of matter, energy and the human body
What is the interrelationships of matter, energy and the human body?
Matter is anything that occupies space and has mass. It is the “stuff” of the universe, how its building blocks are put together and how they react. Matter is part of our daily activities. Examples of matter are found in our own body, in the food we eat, in the air we breathe, in the people we meet. Matter takes three physical forms. It may be solid, liquid or gas. Solids like bones and teeth have definite shape and volume. Liquids like blood plasma and interstitial fluid have definite volume and conform to the shape of the vessel. Gases have neither definite shape nor a definite volume. The air we breathe is a gas. Matter can be changed both physically and chemically. Physical changes do not alter the basic nature of substance, like melting of ice and cutting of food into small pieces. Chemical changesdo alter the composition of a substance. Examples include fermentation of grapes to make wine and the digestion of food.
All living systems can be described by the flow of energy through them. Energy enables simple form of matter to be changed into more complex forms. It is needed to maintain this complexity. Energy is commonly defined as the capacity to do work, or to put matter into motion. The two forms of energy are potential energy and kinetic energy. Kinetic energy is the energy in motion while potential energy is the energy at rest. All living things are built of matter, and to be able to grow and function they require a continuous supply of energy.
Forms of Energy
- Chemical energy is the energy stored in the chemical substances. All body activities are affected by the chemical energy of foods we eat.
- Electrical energy is produced from the movement of charged particles. In our body, an electrical current is generated when charge particles (called ions) move across cell membrane.
- Mechanical energy is the energy directly involved in the moving of matter. The movement of muscles and bones are examples of mechanical energy produced by the body.
- Radiant Energy is the energy that travels in waves like the energy of the electromagnetic spectrum that includes x-rays, and infrared, light, radio and ultraviolet waves. Ultraviolet waves stimulate our bodies to make Vitamin D.
- Light energy is important in vision since it stimulates the retina of our eyes.
Chemistry and the Human Body
Classification of Matter
Everything consists of matter. Each may differ widely from one another but they have one thing in common and that they occupy space. Thus, matter is anything that occupies space and has mass.
Matter is classified according to complexity into simple substances or complex mixtures. A mixture is a physical combination of two or more substances. Examples are the air we breathe, blood plasma, proteins, carbohydrates and water. Substances are homogeneous because they have uniform appearance and composition. Mixtures are either homogeneous or heterogeneous. Homogeneous mixtures are called solutions. Solutions are responsible for maintaining the integrity of cells and transmitting nerve impulses to the brain. Heterogeneous mixtures do not have uniform composition. like colloids and suspensions. Colloids have particles of just the right size to be able to scatter light. Suspensions are combinations in which one substance is uniformly distributed through another without dissolving it.
Elements and compounds are the two classes of homogeneous substances. Elements are fundamental substances, which cannot be decomposed by chemical means. They combine to form compounds. They are classified into metals, nonmetals and metalloids. Metals exhibit metallic luster, malleability, ductility, and electrical conductivity. Nonmetals exhibit properties opposite of metals. Metalloids have properties of both metals and nonmetals.
Compounds are classified into inorganic and organic compounds. The chemical compounds that characterize living things are called organic compounds. They always contain carbon. The main types of organic compounds are carbohydrates, proteins and fats. The glucose that circulates in the blood as food for the cells is an example of carbohydrates in the body. Fats or lipids are stored for energy, insulation and protection for the body organs. Proteins are the structural materials for the body found in muscles, bones and connective tissues. Organic compounds must be taken in as part of a normal diet.
Inorganic compounds do not contain carbon. They can be classified into an acid or a base depending on its color reaction to litmus paper. Acids turn blue litmus paper to red while bases turn red litmus paper to blue. An acid is a chemical substance capable of donating a hydrogen ion to another substance. Hydrochloric acid found in stomach juices is a common example of an acid. A base is a chemical substance usually containing a hydroxide ion that accepts a hydrogen ion. An example of a base is sodium hydroxide. Compounds formed by the combination of an acid and a base is a salt.
Common Elements Found in the Human Body
Everything in this world is either an element or a combination of elements. Each element is composed of tiny particles of matter called atoms. The atom of one element is different from those of all other elements. There are 111 elements and 92 of these occur naturally, the rest are produced artificially. About 90% of our body is composed of carbon, hydrogen, oxygen, and nitrogen and several others are present in a small or trace amounts. The most abundant elements found in our body are calcium, carbon, chlorine, iron, magnesium, nitrogen, oxygen, phosphorus, sodium, and sulfur. Chemist uses symbol to stand for each element. For example, C stands for carbon, O for oxygen and Ca for Calcium.
These are the common elements found in the human body:
Hydrogen (H) - a component of organic molecules and forms of influences the pH of the body fluids.
Carbon (C) - the primary elemental component of all organic compounds, including carbohydrates, proteins, liquids and acids.
Nitrogen (N) - a component of proteins and nucleic acids (genetic materials).
Oxygen (O) - a major component of both organic and inorganic molecules as a gas, essential to the oxidation of glucose and other food fuels during which cellular energy (ATP) is produced.
Sodium (Na) as an ion is the major extracellular cation. It is important for water balance, conduction of nerve impulse and muscle contraction.
Magnesium (Mg) - present in bones and important cofactor for enzyme activity in a number of metabolic reactions.