1. How is an element different from a compound?
2. What would be the pH of a neutral solution?
acidic solution?
basic solution?
3. What four elements are most often found in organic
compounds?
4. Covalent bonds are formed by the sharing of electrons.
How many covalent bonds can a carbon atom form?
5. Turn in Biological Molecule hand out from Yesterday
Carbohydrates
1. Chemical Composition
 Carbohydrates contain atoms of carbon, hydrogen, and oxygen that
are bonded together by the sharing of electrons (covalent bonds).
Energy is stored in these bonds.
 The simplest carbohydrates are the simple sugars or
monosaccharides. The most important monosaccharide for living
things is glucose (molecular formula = C6H12O6). Nearly all living
things use glucose as a source of energy.
Please draw the structural formula for glucose in you class notes:
2. Sugars (carbohydrates) are biologically important because they
contain large amounts of energy. The human body uses glucose
for energy. Carbohydrates that are not immediately used by the
body are stored as complex sugars known as starch. They are
later broken down into simple sugars (glucose) when energy is
needed.
3. Dietary Sources of Carbohydrates
Carbohydrates (sugars) are obtained by eating vegetables,
fruits, breads, cereals, rice, pasta, and sweets. Roughage, such
as cellulose, is a special type of complex carbohydrate that
cannot be digested by humans.
4. Carbohydrate Storage
Unused carbohydrates are stored in the liver as a complex
carbohydrate called glycogen.
Check Your Understanding
1. What is the molecular formula for glucose?
2. If glucose is a monosaccharide, what does a
disaccharide look like? Polysaccharide?
3. What are the functions of cellulose and glycogen?