1. Characteristics and Classification of Life
Chapter 2
Characteristics
and
Classification of Life

2. Chapter 2B
Molecules and Life

3. II. Molecules and Life
A. Molecules

4. Molecules
The simplest structural unit of an element or compound.

5. A. Molecules Made of smaller units called atoms.
There are many different types of molecules in each living cell.

6. A. Molecules Four general categories of molecules in cells:
1. Carbohydrates
2. Lipids (fats)
3. Proteins
4. Nucleic acids

7. 1. Carbohydrates Important storage molecule
Made only of carbon, hydrogen, and oxygen atoms
Sugars and starches
Glucose (most common)
Cellulose, starch, glycogen

8. 2. Lipids Important storage, structural, and transport molecule
Made only of carbon, hydrogen, and oxygen atoms
Energy storage
Main component of cell membranes

9. 3. Proteins Building blocks for different parts of a cell.
Enzymes: regulate life-supporting processes
Composed of amino acids

10. 4. Nucleic Acids
Contain all the instructions that living cells need to make proteins and maintain life
Composed of nucleotides
Examples: DNA and RNA

11. Nucleic Acids DNA and RNA
The arrangement of the nucleotides in DNA forms a code.
The DNA code determines the order of amino acids in a protein.

12. Nucleic Acids DNA and RNA
RNA helps make proteins by using the coded instructions in DNA.