1. 9/23/2011
Objective: Describe properties of each of the four classes of macromolecule
Warm-Up: Write down two questions you have from this week.

2. Properties of Biological Macromolecules
23 September 2011

3. Organic Molecules Molecules containing carbon are called organic
Exception: Carbon monoxide and carbon dioxide are not organic
Note: Water is inorganic!
Carbon is unique because it can make 4 covalent bonds
This means that carbon can form rings, chains, and branching molecules
Many different structures = many different functions
These large, organic molecules are called macromolecules
30% of your cells’ cytoplasm is organic material

4. Polymers and Monomers The biological macromolecules are polymers
This means that they are large molecules constructed of repeating smaller units
The smaller units—the building blocks—are called monomers
Keep in mind that “polymer” is a generic category; carbs, proteins, etc. are specific examples of polymers
“Monomer” is also a generic category; amino acids, monosaccharides, and nucleotides are specific monomers

5. Carbohydrates Made of monosaccharides
In animals, used primarily for short-term energy
Carbon-carbon bonds store energy
Breaking those bonds releases energy
In a long chain of carbons, there is a lot of energy!
Cells use glucose for energy
In animals, excess glucose is stored as glycogen in the liver
In plants, excess glucose is stored as starch
Cellulose, a carbohydrate made of very long glucose chains, provides structure to cell walls

6. Glucose

7. Lipids Long-term energy storage and cell membranes Triglycerides
A special class of lipids called phospholipids make up the cell membrane
Triglycerides
Simple fats made up of one molecule of glycerol and three fatty acids
There are many different fatty acids
Fats have different properties depending on the fatty acids present
Unsaturated fatty acids are liquid at room temperature
Saturated fatty acids are solid

9. Proteins There are 20 different amino acids
Each protein has a unique amino acid sequence
The amino acid sequence is referred to as the protein’s primary structure
Each amino acid has a unique chemical structure, giving it unique chemical characteristics
The bond between two amino acids is called a peptide bond
A chain of amino acids is therefore called a polypeptide
Long polypeptide chains fold into proteins

10. Proteins (cont)
A chain of amino acids will “fold” and “twist” because of interactions between the chemical group
This is called secondary structure
Amino acids that are hydrophobic will “fold” to the inside of the chain
The organized chains of amino acids will continue to fold into a more complex three-dimensional shape
The protein’s three-dimensional shape is its tertiary structure
A PROTEIN’S 3D SHAPE DETERMINES ITS FUNCTION
Some proteins have a quaternary structure, which occurs when two or more tertiary forms interact

12. Nucleic Acids
Nucleotides have three parts: a sugar, a phosphate group, and a nitrogen base
Each nucleotide has a unique nitrogen base
Different nucleic acids use different sugars
DNA uses deoxyribose
RNA uses ribose
In double-stranded DNA, there is hydrogen bonding between nitrogen bases that holds the two strands together

14. Dehydration Synthesis
When a peptide bond forms between two amino acids, a molecule of water is released from the two amino acids
The same thing happens when two molecules of glucose bond, and when a fatty acid bonds to glycerol
Dehydration = loss of water
Synthesis = to make
When these bonds are made, water is “lost” from the molecules