Molecules of Life

All living organism pass information from one generation to the next with genetic material containing the information needed to construct a complete organism. The number of genes vary from organism to organism.

What are genes?

The gene is the unit of genetic infomation. More complex organisms require a greater number of genes to perform life functions. A gene does not function autonomously, but relies upon other cellular components for its function.All cellular activities obey the known laws of physics and chemistry.

What are genes made of?

All genes regardless of the type of organism are made of the same basic building blocks called nucleic acids. These nucleic acids combine to form long strands know as deoxyribonucleic acid (DNA). There are four different types of DNA adenine (A), cytosine (C), thymine (T), Guanine (G)

Adenine Thymine
Guanine Uracil

DNA is almost a universal genetic material. All know living organisms and many viruses have DNA as their genetic material. Some viruses however, use an alternative nucleic acid, know as ribonucleic aicd (RNA).


dna molecule

DNA image cross-section --See the DNA molecule using Jsmol

What do genes do?

Each gene codes for a different protein. The relationship between a sequence of DNA and the sequence of the corresponding protein is know as the genetic code. Protein synthesis is the process by which cells make protein using genetic information.

Proteins are used to build and repair body parts. All parts of your body contain protein e.g., blood, muscles, brain, skin, and hair.


A protein is a complex, high molecular weight organic compound that consists of amino acids joined by peptide bonds. Protein is essential to the structure and function of all living cells and viruses. Many proteins are enzymes or subunits of enzymes. Other proteins play structural or mechanical roles, such as those that form the struts and joints of the "cytoskeleton." Proteins are also nutrient sources for organisms that do not produce their own energy from sunlight. Proteins differ from carbohydrates chiefly in that they contain much nitrogen and a little bit of sulfur, besides carbon, oxygen and hydrogen. Proteins are a primary constituent of living things. Below is a table showing all the amino acids that are used to build protein structures.

Alanine Arginine
Asparagine Aspartic Acid
Cysteine Glutamic Acid
Glycine Histidine
Leucine Lysine
Isoleucine Methionine
Phenylalanine Proline
Serine Tryptophan
Tyrosine Valine

Molecules of Life -- The Energy Rich Molecules

All cells require a constant supply of energy to generate and maintain their e biological function. This energy comes from the chemical bond energy in food molecules, which serve as the source of fuel for cells. Energy in cells are stored in energy rich compounds. Some examples are shown below.


Protein Complexes

insulin molecule

Insulin Molecule

Signaling Molecules

Nitric Oxide