The Chemistry of Life
Chemical bonds join together the molecules and compounds of life. Water and carbon compounds play essential roles in organisms, which carry out chemical reactions in their daily life processes.
2.1 The Nature of Matter
The subatomic particles that make up atoms are protons, neutrons, and electrons. All isotopes of an element have the same chemical properties, because they have the same number of electrons. The physical and chemical properties of a compound are usually very different from those of the elements from which it is formed. The main types of chemical bonds are ionic bonds and covalent bonds.
2.2 Properties of Water
Water is a polar molecule. Therefore, it is able to form multiple hydrogen bonds, which account for many of its special properties. Water’s polarity gives it the ability to dissolve both ionic compounds and other polar molecules. Buffers play an important role in maintaining homeostasis in organisms.
ONLINE RESOURCES
Simulation - Dissolution Process
PhET - pH Scale: Basics
PhET - Sugar and Salt Solutions
PhET - Acid-Base Solutions
2.3 Carbon Compounds
Carbon can bond with many elements, including hydrogen, oxygen, phosphorus, sulfur, and nitrogen to form the molecules of life. Living things use carbohydrates as their main source of energy. Plants, some animals, and other organisms also use carbohydrates for structural purposes. Lipids can be used to store energy. Some lipids are important parts of biological membranes and waterproof coverings. Nucleic acids store and transmit hereditary, or genetic, information. Some proteins control the rate of reactions and regulate cell processes. Some proteins build tissues such as bone and muscle. Others transport materials or help to fight disease.
ONLINE RESOURCES
Cpalms - The Macromolecules of Life: Overview
2.4 Chemical Reactions and Enzymes
Chemical reactions always involve changes in the chemical bonds that join atoms in compounds. Chemical reactions that release energy often occur spontaneously. Chemical reactions that absorb energy will not occur without a source of energy. Enzymes speed up chemical reactions that take place in cells. Temperature, pH, and regulatory molecules can affect the activity of enzymes.