1. The four primary organic macromolecules
Proteins (polypeptides) are made up of chains of amino acids
There are 20 different types of amino acids, each with the same basic starting structure plus an additional functional group (R)
Basic structure of an amino acid

2. The four primary organic macromolecules
Proteins (polypeptides) are made up of chains of amino acids
The amino acids are linked together via peptide bonds

3. The four primary organic macromolecules
Proteins (polypeptides) are made up of chains of amino acids
Characteristics of the reactive groups cause regions of the protein to attract or repel one another, causing the protein to fold into its final shape

4. The four primary organic macromolecules
Proteins (polypeptides) are made up of chains of amino acids
Characteristics of the reactive groups cause regions of the protein to attract or repel one another, causing the protein to fold into its final shape
Primary Structure – linear amino acid sequence

5. The four primary organic macromolecules
Proteins (polypeptides) are made up of chains of amino acids
Characteristics of the reactive groups cause regions of the protein to attract or repel one another, causing the protein to fold into its final shape
Primary Structure
Secondary Structure
– folding into helices and beta sheets

6. The four primary organic macromolecules
Proteins (polypeptides) are made up of chains of amino acids
Characteristics of the reactive groups cause regions of the protein to attract or repel one another, causing the protein to fold into its final shape
Primary Structure
Secondary Structure
Tertiary Structure – folding into final 3D shape

7. The four primary organic macromolecules
Proteins (polypeptides) are made up of chains of amino acids
Characteristics of the reactive groups cause regions of the protein to attract or repel one another, causing the protein to fold into its final shape
Primary Structure
Secondary Structure
Tertiary Structure
Quaternary Structure
– folding into final 3D shape (does not apply to all proteins)
Hemoglobin (the oxygen-binding component of blood) is composed of eight proteins: four hemes, two alpha globulins, and two beta globulins

8. The four primary organic macromolecules
Proteins (polypeptides)
Structural
Receptors
Enzymes
Actin is an important structural protein in the cellular cytoskeleton and the fibers within muscle cells that enable them to contract

9. The four primary organic macromolecules
Receptors communicate information by causing conformational (shape) changes that transmit a signal cascade (like dominoes falling down)
Proteins (polypeptides)
Structural
Receptors
Enzymes
Ligands are the generic name for molecules that specifically bind to receptors (cause receptor to undergo conformational change)

10. The four primary organic macromolecules
substrate
Proteins (polypeptides)
Structural
Receptors
Enzymes
enzyme
Enzymes are proteins that speed up chemical reactions by helping to bring molecules together in favorable conformation (biological catalysts)
Substrates are the molecules (reactants) bound by the enzyme, the enzyme’s active site specifically binds to them
Enzymes are not altered by the chemical reaction and therefore can act again and again to catalyze the reaction over and over

11. The four primary organic macromolecules
Endergonic reactions
Proteins (polypeptides)
Structural
Receptors
Enzymes
heat
Energy is stored in chemical bonds
Endergonic reactions are ones where the energy in the bonds of the products exceeds the energy in the bonds of the reactants
heat A B
Acetic Acid
Sodium Bicarbonate
Sodium Acetate
water
HC2H3O2 + NaHCO3
NaC2H3O2 + H2O + CO2
Carbon Dioxide

12. The four primary organic macromolecules
Exergonic reactions
Proteins (polypeptides)
Structural
Receptors
Enzymes
heat
Energy is stored in chemical bonds
Endergonic reactions are ones where the energy in the bonds of the products exceeds the energy in the bonds of the reactants
Exergonic reactions are ones where the energy in the bonds of the reactants exceeds the energy in the bonds of the products (energy is left over at the end of the reaction
It takes energy to break all chemical bonds, even if the reaction is exergonic = activation energy
NaCl + H2O
NaOH + HCl
+ heat A B
Sodium chloride
water
Sodium hydroxide
Hydrogen chloride

13. The four primary organic macromolecules
Heat speeds up reactions by causing molecules to move faster, thereby encountering one another more frequently and with greater force
Enzymes reduce the activation energy needed for a chemical reaction to occur
helps reactants encounter one another at necessary angle more quickly
Puts stress on bonds so they break more easily
Proteins (polypeptides)
Structural
Receptors
Enzymes

14. The four primary organic macromolecules
Most enzyme names end in “ase” - means “to cut”
Chemical reactions (metabolism) would happen too slowly in the body without enzymes
Proteins (polypeptides)
Structural
Receptors
Enzymes

15. Click here for Enzyme examples: