Day 1 Structure of Proteins/Amino Acids Proteins in Food Day 2 Protein Synthesis Protein Shape

Vocabularies REVIEW - NEW - Monomer Di/Tri/Oligopeptide Polymer Amino acid Polypeptide Peptide bond Carboxyl group Condensation Reaction NEW - Di/Tri/Oligopeptide Polypeptide Amino group R-group Transamination Bioavailability Most proteins are about 250 to 300 amino acid long

Amino Acids The carboxyl group often loses it’s hydrogen atom and becomes negatively charged. The amino group often gains an hydrogen group and becomes positively charged. http://www.learners.in.th/blogs/posts/264172

The chemical and physical properties of of amino acids depend on subtle differences in the R-groups. Some R-groups are negatively charged, some are positively charged, and others have no charge at all. http://www.geneinfinity.org/images/aminoacids.jpg

Transamination The process of synthesizing nonessential amino acids Transfer of an amino group from an amino acid to an alpha-keto acid Some infants born prematurely cannot make several of the nonessential amino acids. When this happens, some nonessential amino acids become conditionally essential because they must be obtained from the diet until the baby matures. Pre-matured sometimes need fortify milk with conditionally essential amino acids to ensure optimal growth and development.

Complete and Incomplete Proteins Meat, poultry, fish, eggs, dairy products, etc. Also in legumes: beans, peas, peanuts, etc. Nitrogen fixing bacterial Some foods contain more essential amino acids than others Complete protein sources (animal products) Incomplete protein sources (plant products) limiting amino acids Leguminous plans are unique in that their roots are associated with bacteria that can take nitrogen from the air and incorporate it into amino acids (most plants can only get nitrogen from the soil). These amino acids are often used by the associated plants. This is why legumes tend to have higher protein content than most other plants.

Protein Complementation A dietary practice (for vegetarians) Combining a variety of food with incomplete proteins Rice and bean Corn and beans

Protein Quality Presence of essential amino acids Amount of essential amino acids The body’s ability to absorb the amino acids (bioavailability) High-quality protein source Low quality protein sources Scientists are now able to alter the amino acid composition of some plants to make them high-quality sources.

Day 1 Review What is the structure of an amino acid? What is a complete protein? What is a high-quality protein? What is an limiting amino acid? The amino acid that are missing or in low amounts in an imcomplete protein source are called limiting amino acid.

Vocabularies Protein Shape Protein Synthesis Primary, secondary, tertiary, quaternary structures Α-helix Β-folded sheets denaturation Protein Synthesis RNA Transcription Translation

The Central Dogma evolvingscientist.net & ncbi.nlm.nih.gov Note: after translation, the amino acid chain is not yet a functional protein because it is a linear polypeptide (primary structure). A functional protein needs to be folded and often combined with other proteins. evolvingscientist.net & ncbi.nlm.nih.gov

Animation & Video Protein Synthesis Protein synthesis video http://sepuplhs.org/high/sgi/teachers/genetics_act16_sim.html Protein synthesis video Protein synthesis activity Sickle cell anemia video http://www.dnalc.org/resources/3d/17-sickle-cell.html http://www.pbs.org/wgbh/evolution/library/01/2/l_012_02.html

Primary Structure: amino acid sequence is critical to its funciton because it determines the protein’s most basic chemical and physical characteristics. The primary structure represents the basic identity of the protein Secondary Structure: 3D folding due to the attraction between negatively charged amino group (NH2) and carboxyl group (COOH) forming hydrogen bonds between amino acids

Tertiary Structure: attraction between the R-groups of different amino acids, specifically those with sulfur. The sulfur-sulfur (disulfide) bonds are particularly stable. Quaternary Structure: two or more polypeptides come together forming one big structure, i.e. hemoglobin http://schoolworkhelper.net/protein-structures-primary-secondary-tertiary-quaternary/

The quaternary structure of some proteins (such as hemoglobin) include nonprotein components called prosthetic groups, which often contains minerals

www.wikipedia.org

Denaturing Agents Chemical Agents Detergents Acids Bases Salts Alcohol Metals Physical Agents Shaking Beating Heating Examples Mercury poisoning Beating of egg white The structure of a protein determines its shape, which determines its function. When the shape of a protein is disrupted, it is to say that the protein is denatured. Denaturation occurs when a protein unfolds and loses its secondary, tertiary, and quaternary structures, but maintains its primary structure.