Biology 211 Anatomy & Physiology I Chemistry

Recall: SYSTEMS are composed of one or more organs, all serving a common function ORGANELLES are composed of different types of molecules, all serving a common function ORGANS are composed of one or more types of tissues, all serving a common function TISSUES are composed of one or more types of cells and their products, all serving a common function CELLS are composed of different types of organelles, all serving a common function MOLECULES are composed of different types of atoms, all serving a common function

While many types of atoms are important in human physiology, 96% of the mass of the human body is composed of just four elements: These form the macromolecules which compose the organelles of all cells in the body Other elements, in very small concentrations, are primarily found as ions: e.g. Ca ++, Na +, K +, Mg +, Fe +++, Cl -

We will not cover details of atomic structure and bonding in lecture. These are described in your Saladin textbook. You are responsible for studying this material and becoming familiar with the information. Specifically. you need to understand: a) How protons, neutrons, and electrons form atoms; including how to determine atomic number, atomic mass, and electrical charge b) What ions and electrolytes are, and how these are important in human physiology c) How chemical formulae are written: Structural; Condensed structural; Molecular d) How covalent, ionic, and hydrogen bonds form e) Differences among mixtures, colloids, solutions, and suspensions more ….

We will not cover details of atomic structure and bonding in lecture. These are described in your Saladin textbook. You are responsible for studying this material and becoming familiar with the information. You also need to know the structures of the following “functional groups” as shown in your text Amino group Carboxyl group Hydroxyl group Methyl group Phosphate group

In nature (including living cells), molecules are constantly being broken apart to form smaller molecules, or added together to form larger molecules

Two examples of exchange reactions

These chemical reactions occur rapidly for certain reactions and very slowly for others Fortunately, certain substances, called catalysts, can make slow reactions proceed much more quickly. In physiology, these catalysts are proteins called enzymes

These reactions, building up and breaking down molecules with the assistance of enzymes, are constantly occurring within cells. They allow the cell to carry out its normal functions: - Build organelles - Synthesize hundred of different types of molecules - Store nutrients until it needs them - Metabolize fuels to produce energy - Get rid of wastes etc.