1. KEY CONCEPT Carbon-based molecules are the foundation of life.

2. I. Carbon atoms have unique bonding properties.
A. Carbon forms covalent bonds with up to four other atoms, including other carbon atoms.
B. Carbon-based molecules have three general types of structures.
1. straight chain
2. branched chain
3. ring

3. C. Many carbon-based molecules are made of many small subunits bonded together.
1. Monomers are the individual subunits.
2. Polymers are made of many monomers.

4. II. Four main types of carbon-based molecules are found in living things.
A. Carbohydrates are made of carbon, hydrogen, and oxygen.

5. II. Four main types of carbon-based molecules are found in living things.
A. Carbohydrates are made of carbon, hydrogen, and oxygen.
1. Carbohydrates include sugars and starches.

6. 2. Carbohydrates can be broken down to provide energy for cells.
3. Some carbohydrates are part of cell structure.
Polymer (starch)
Starch is a polymer of glucose monomers that often has a branched structure.
Polymer (cellulose)
Cellulose is a polymer of glucose monomers that has a straight, rigid structure
monomer

7. B. Lipids are nonpolar molecules that include fats, oils, and cholesterol.
Triglyceride

8. C. Lipids have several different functions.
1. broken down as a source of energy
2. make up cell membranes
3. used to make hormones

9. C. Phospholipids make up all cell membranes.
1. Polar phosphate “head”
2. Nonpolar fatty acid “tails”
Phospholipid

10. D. Proteins are polymers of amino acid monomers.
1. Twenty different amino acids are used to build proteins in organisms.

11. E. Proteins differ in the number and order of amino acids.
1. Amino acids interact to give a protein its shape.
hydrogen bond
Hemoglobin
2. Incorrect amino acids change a protein’s structure and function.

12. F. Nucleic acids are polymers of monomers called nucleotides.

13. F. Nucleic acids are polymers of monomers called nucleotides.
1. Nucleotides are made of a sugar, phosphate group, and a nitrogen base.
A phosphate group
nitrogen-containing molecule, called a base
deoxyribose (sugar)

14. F. Nucleic acids are polymers of monomers called nucleotides.
1. Nucleotides are made of a sugar, phosphate group, and a nitrogen base.
2. DNA stores genetic information.
DNA
3. RNA builds proteins.
RNA