Protein

Macromolecules: Proteins Proteins taken in as food (meat, dairy, eggs, beans, nuts) are different than our proteins. They must be broken down into amino acids by adding water. Recall Carbohydrates and Lipids The process is… Hydrolysis. To build proteins water must be removed in the process of…. Dehydration Synthesis.

Proteins: CHON(S) peptide bond Proteins are large complex polypeptides. Needed for structure: muscles, skin, cell membranes, and enzymes Made of amino acids Amino acids are joined by peptide bonds A string of peptides is also called a polypeptide peptide bond

Proteins: Structure Amino acids have three parts: The 20+ amino acids differ only in their R-group

Generalized Formula for Amino Acid H Acid group R C COOH NH2 Rest of the molecule Amino group

Amino Acid Groups H NH2 = N H O Double Bond COOH = C O H

Macromolecules: Proteins Peptide bonds join amino acids when dehydration synthesis occurs. An OH from the acid group of one amino acid joins to an H from the amino group of the other amino acid. A water molecule is formed, and a C-N bond is formed between the two amino acids. The C-N bond is called a peptide bind. Dipeptide: 2 amino acids joined Polypeptide: 3 or more amino acids joined.

Dehydration Synthesis Prentice Hall, Biology

Proteins: Structure The protein you end up with depends on: which amino acids were chosen, their order (sequence), and how many of each Who decides? The DNA

Proteins: Structure Valine Leucine Glutamic Acid Compare 3 amino acids: Valine Leucine Glutamic Acid

Proteins: Enzymes Enzymes are proteins that act as a catalyst. (Catalysts are substances that increase the rate of a chemical reaction.) Enzymes are not used up or changed by a reaction. Enzymes are specific in their actions. Enzymes work best under specific conditions.

Category 2 Category 1 Let’s Review What is the name of this unit? Category 3 Category 4