Compounds Essential to Life
Organic Chemistry/Biochemistry
1: Compounds Important to Life
• Biologists classify compounds into organic compounds and inorganic compounds.
Organic Compound: a compound that is derived from living things and contains carbon
Inorganic Compound: a compound generally derived nonliving things
• Water
Water is an inorganic molecule with unique properties that make it one of the most important compounds for living things.
In the water molecule (H2O), the hydrogen and oxygen atoms bond so that the electrical charge is unevenly distributed.
The area of the molecule containing oxygen has a slightly negative charge, and the areas containing hydrogen have slightly positive charges.
Polar Compound: a compound with one side having a negative charge and the other side a positive charge
Hydrogen bonds form between water molecules.
• Six Unique Properties of Water
1. Universal Solvent: Water is an excellent solvent due to its polarity. When ionic compounds interact with water, the compounds often break apart or dissociate into ions. 2. Surface Tension: Water’s high surface tension is due to the cohesion of its molecules.
3. Capillary Action: The ability of a liquid to move upward against the force of gravity by molecular attraction to a surrounding surface (adhesion).
4. Resistance to Temperature Change: When water is heated, most of the heat energy goes into breaking the hydrogen bonds between the molecules. Only after the bonds have been broken will the heat energy increase the motion of the molecules and thus raise the temperature of the water.
5. High Heat of Vaporization: At 100 °C & 1 atm, it takes 540 cal to change 1 g of water to vapor.
6. Freezing: The molecules of water move apart to maintain the maximum # of H bonds.
Therefore, the density of ice (0.92 g/cm
3
) is less than the density of water (1.00 g/cm 3
).
• Carbon Compounds
A carbon atom has four electrons in its outer energy level. Carbon
1: Compounds Important to Life
• Biologists classify compounds into organic compounds and inorganic compounds.
Organic Compound: a compound that is derived from living things and contains carbon
Inorganic Compound: a compound generally derived nonliving things
• Water
Water is an inorganic molecule with unique properties that make it one of the most important compounds for living things.
In the water molecule (H2O), the hydrogen and oxygen atoms bond so that the electrical charge is unevenly distributed.
The area of the molecule containing oxygen has a slightly negative charge, and the areas containing hydrogen have slightly positive charges.
Polar Compound: a compound with one side having a negative charge and the other side a positive charge
Hydrogen bonds form between water molecules.
• Six Unique Properties of Water
1. Universal Solvent: Water is an excellent solvent due to its polarity. When ionic compounds interact with water, the compounds often break apart or dissociate into ions. 2. Surface Tension: Water’s high surface tension is due to the cohesion of its molecules.
3. Capillary Action: The ability of a liquid to move upward against the force of gravity by molecular attraction to a surrounding surface (adhesion).
4. Resistance to Temperature Change: When water is heated, most of the heat energy goes into breaking the hydrogen bonds between the molecules. Only after the bonds have been broken will the heat energy increase the motion of the molecules and thus raise the temperature of the water.
5. High Heat of Vaporization: At 100 °C & 1 atm, it takes 540 cal to change 1 g of water to vapor.
6. Freezing: The molecules of water move apart to maintain the maximum # of H bonds.
Therefore, the density of ice (0.92 g/cm
3
) is less than the density of water (1.00 g/cm 3
).
• Carbon Compounds
A carbon atom has four electrons in its outer energy level. Carbon