Chapter 16.1 Functions of Proteins SWBAT: Classify proteins by their functions in the cells
What are proteins Protein Bozeman
Proteins Proteins are polymers of amino acids chemically bonded to each other All proteins in humans are made up from 20 different amino acids Identification: many protein names end with – in, -en, -ase
Types of Proteins 1. Structural – collagen Also Keratin for hair and nails
2. Contractile Proteins Actin/Myosin in muscles) Provide movement muscle contraction
3. Transport Protein Cross Membrane Transport membrane crossing Oxygen Transport: Hemoglobin
4. Storage proteins Example: Casein (cows) amino acid storage in milk Human (albumin)
5. Protein Hormones Regulation of Metabolism Insulin- blood sugar regulation
6. Enzymes Speed up reactions in the body Example: Lactase breaks down Lactose into Galactose and Glucose How Enzymes work
7. Immune Proteins Defend body against pathogens Example: Antibodies Antibody function
Table 16.1 – page 534
Chapter 16.2 Amino Acids SWBAT: know the structure of an amino acid and be familiar with the classification of amino acids
AA are all the same with regard to 1. Central carbon 2. Amino group 3. Carboxyl group 4. Extra Hydrogen Differ with regard to the R-side chain Anatomy of an Amino Acid
Acid/Base behavior of functional groups At normal body pH (~7.4) the amino and carboxyl group exist in their charged version COO - carboxylic acids are acids: release a proton H+ NH 3 + amines are bases: accept a proton H+ Called a Zwitterion: positively and negatively charged at the same time!!!
Side Chain (R) Group can be: 1. Alkyl 2. Hydroxyl 3. Thiol 4. Amino 5. Carboxyl 6. Aromatic 7. Cyclical 8. Amide Amino Acid (R) Group
Classification of Amino Acids Non-polarPolar Neutral (not charged) Positively charged (Basic) Negatively charged (Acidic) Charged Amino Acid
Nonpolar Amino Acids R can be: Alkyl side chain Aromatic side chain
Polar Amino Acids R can be: Hydroxyl (-OH) Thiol (-SH) Amide (-CONH 2 ) These can H- bond with water
Acidic Amino Acids R will be: Carboxylic acid (-COOH) Can ionize as a weak acid
Basic Amino Acids R group will contain: an amino group that ionizes as a weak base
Amino acids (except Glycine) are chiral – can exist as D or L enantiomers Fisher projections: Highest oxidized C on top: COOH R side chain at bottom L - isomer – NH 2 group on left D - isomer – NH 2 group on right Amino Acid Stereoisomers L-serine D-serine Only L-amino acids form proteins!