Enero 30, 2012

Chapter 2: The Chemical Basis of Life

    In this section, tells us the chemicals that are present in our body and their relations with one another to make our body function. This is just a review on what we have learned in our Chemistry lesson.

     We have already studied during our high school days about matter. MATTER is anything that occupies space and has mass. Mass is the amount of matter in an object.

     An element is the simplest type of matter with unique chemical properties while an atom is the smallest particle of an element that has the characteristics of that element.

     A molecule is formed when two or more atoms chemically combine to form a structure that behaves an independent unit while compound as a substance composed of two or more different types of atoms that are chemically combined.
      A compound is a substance composed of two or more different types of atoms that are chemically combined.
note: Not all molecules are compounds.

    Chemical reaction is a process that leads to the transformation of one set of chemical substances to another.
1. Synthesis
          In synthesis reaction, two or more simple substances combine to form a more complex substance. Two or more reactants yielding one product is another way to identify a synthesis reaction. For example, simple hydrogen gas combined with simple oxygen gas can produce a more complex substance, such as water. Water is removed (dehydration) to form bonds.
A + B -e-n-e-r-g-y-> A---B + water

2. Decomposition
          A decomposition reaction is the opposite of a synthesis reaction, where a more complex substance breaks down into its more simple parts.
A---B -----w-a-t-e-r-----> A + B

3. Reversible
         In reversible reaction, the product can be changed to reactant.
A + B<--> A--B   

     Energy is the capacity to do work. It can be divided into two: POTENTIAL ENERGY and KINETIC ENERGY.

Potential energy is an energy at rest.

Kinetic energy is energy in motion.

Mechanical energy is the sum of kinetic and potential energy. Other forms of energy are chemical energy, heat energy, electric energy, and radiant energy.

Breathing involves mechanical energy.
     The total energy of the universe is constant therefore, energy is neither created nor destroyed.
One type of energy can be changed into another here is an example:

As a moving object slows down and comes to rest, its kinetic energy is converted into heat energy by friction.

     An acid is a substance which reacts with a base. It can be identified as tasting sour. It is a proton donor because a hydrogen atom without its electron is a proton, any substance that releases hydrogen ions in water is an acid. Base is a substance that can accept protons or hydrogen ions.
     Acids and bases can be classified as strong or weak. Strong acids or bases disassociate almost completely when dissolved in water. Weak acids or bases only partially disassociate in water.

The picture below is what they call the pH scale, this indicates the hydrogen ion concentration of a solution.
Values less than 7 are acidic (the lower the number, the more acidic). Values greater than 7 are basic (the higher the number, the more basic).

  • Many fluids in humans function within a narrow pH range. An illness occurs when pH changes. Normal blood pH is 7.35 to 7.45. pH greater than 7.5 results to ALKALOSIS while pH lesser than 7.3 results to ACIDOSIS. Each of these can lead to death if not rapidly corrected.

     A buffer is an aqueous solution that has a highly stable pH. If you add acid or base to a buffered solution, its pH will not change significantly. Similarly, adding water to a buffer or allowing water to evaporate will not change the pH of a buffer.

     Inorganic chemistry is mostly concerned with non-carbon-containing substances but does include such carbon-containing substances as carbon monoxide, carbon dioxide and bicarbonate ion.
     Inorganic substances are small compounds that do not contain carbon and hydrogen. They usually disassociate in water forming ions (electrolytes).


  • Polar molecule that demonstrates hydrogen bonding.
  • Many solutes are dissolved in our body's water; many ionic compounds disassociate in water.
  • Participate in many chemical reactions such as dehydration (synthesis) and hydrolysis (degradation).
  • Excellent temperature buffer.
  • Excellent cooling mechanism
  • Lubricant

  • Gas that is transported in the blood.
  • Used to release energy from nutrient molecules.

  • Exhaled during respiration

      Organic chemistry studies the properties of a compounds of carbon that are organic.
There are four major groups of organic that are essential to a living organism.
Here are the following:
  1. Carbohydrates
  2. Lipids
  3. Proteins
  4. Nucleic Acid

CLICK the word A-C-T-I-V-I-T-Y below to sharpen your minds.


End of Chapter 2

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