Protein Proteins are found throughout living organisms. They make up structural parts of cells and body tissue. They form cartilage, bone, and muscles Make up hormones, antibodies, and enzymes

Protein Amino acids are compounds with an amino group (–NH2) on one end and a carboxyl group (–COOH) on the other end. Covalent bonds called peptide bonds link amino acids together to form a polypeptide. A protein is a functional molecule built from one or more polypeptides.

Amino Acids Function of Proteins Identify the three amino acids. Explain how they come together to form the peptide bond. Function of Proteins

Structure and Function All amino acids are identical in the amino and carboxyl groups. Any amino acid can be joined to any other amino acid by a peptide bond formed between these amino and carboxyl groups. This is done through dehydration synthesis.

Structure and Function Amino acids differ from each other in a side chain called the R-group, which have a range of different properties. More than 20 different amino acids are found in nature. This variety results in proteins being among the most diverse macromolecules.

Levels of Organization Proteins have four levels of structure. They may form coils, helixes, pleated sheets, and globules. A protein’s primary structure is the sequence of its amino acids. Secondary structure is the folding or coiling of the polypeptide chain.

Levels of Organization Tertiary structure is the complete, three-dimensional arrangement of a polypeptide chain. Proteins with more than one chain have a fourth level of structure, which describes the way in which the different polypeptide chains are arranged with respect to each other. For example, the protein shown, hemoglobin, consists of four subunits.

Types of Proteins There are two types of proteins – fibrous and globular. Fibrous protein (found in skin, tendons, bones, and muscles) does not dissolve in water (hydrophobic). Globular protein (found in enzymes, some hormones, and hemoglobin) can dissolve in water (hydrophilic). This slide is optional. Use if you would like your students to have this additional information regarding proteins. It is also linked to examples of each type of protein.

Fibrous Proteins Keratins are a family of fibrous structural proteins; tough and insoluble, they form the hard but nonmineralized structures found in reptiles, birds, amphibians and mammals. Optional Types of Proteins

Globular Proteins Enzymes are proteins that catalyze (i.e. accelerate) chemical reactions. Almost all processes in a biological cell need enzymes in order to occur at significant rates. Optional Types of Proteins