Proteins Are Essential to the Structure & Activities of Life Dr. E

What is meant by protein conformation? 0 Each type of protein has a unique 3-dimensional shape 0 The 3-dimensional shape is referred to as its conformation 0 It is the proteins unique conformation that gives each type of protein a specific function

Proteins Play many Critical roles 0 Proteins do most of the work in the cell 0 Proteins are required for the structure of living things and thus responsible for the appearance and form of each living thing 0 Proteins are required for cell, tissue, and organ function 0 Proteins regulate body tissues and organs

7 Classes of Proteins 0 1. Structural proteins-Make up components of cell. Hair of mammals (made of protein keratin), silk of spider (made of protein fibroin), and fibers that make up tendons & ligaments (made of protein collagen) are all examples of structural proteins. 0 2.Contractile proteins-Responsible for muscle movement and cell movement. Examples are the proteins myosin and actin that make up muscle.

7 Classes of Proteins- continued 0 3. Storage proteins-These proteins store amino acids for building new proteins. The protein ovalbumin found in egg white stores amino acids for the growing organism. Caesin is a protein stored in milk which serves as the major source of amino acids for baby mammals. Seeds also contain storage proteins because the germinating seedling will need to build proteins to grow.

7 Classes of Proteins- continued 0 4. Defense proteins-Proteins that defend organism against bacteria, viruses, fungi and cancer. Antibodies are proteins that fight infections and cancer Transport proteins-These proteins bind and carry atoms and small molecules within cells and throughout the body. An example is hemoglobin which is a protein that transports oxygen to all your cells.

7 Classes of Proteins- continued 0 6. Signal or messenger proteins-Transmit signals to coordinate biological processes between different cells, tissues, and organs. Most hormones are proteins. For example, insulin is a hormone made by cells in pancreas and released into blood stream when blood sugar is too high. Insulin signals cells to take up sugar from the blood reducing the amount of sugar in the blood.

7 Classes of Proteins- continued 0 7. Enzymes-Proteins that carry out almost all of the thousands of chemical reactions that take place in a cell. Also assist in formation of new molecules by reading the genetic information stored in DNA. Catalase is an enzyme that carries out the chemical reaction: 0 2H 2 O  2H O 2