3.12- Proteins have a wide range of functions and structures

What needs to happen for most proteins to function?

-Binding to another molecule. -In order to bind, needs specific 3-d shape to recognize + attach to the molecule. Eg: lysozyme can destroy bacterial cells. Its specific 3D shape helps it to recognize + attach it to its molecular target.

What are the 2 general shapes of proteins?

-GLOBULAR -Has 3-dimensional structure -Eg: most enzymes like lysozyme (found in sweat, tears, saliva) -FIBROUS -Has 2-dimensional structure -Most structural proteins r fibrous (eg: spider web is made of silk proteins)

What is denaturation?

-The protein's function depends on its specific 3-d shape. Denaturation= when a protein unravels, losing its specific shape and thus function. -Caused by: -Excessive heat -pH change -Change in salt concentration

What are all the functions of proteins?

ENZYMES (enzymes= biological catalysts that speed up reactions in cells). Eg: lactase. TRANSPORT PROTEINS embedded in cell membranes that move nutrients in and out of cells. DEFENSIVE PROTEINS. Eg: Antibodies. SIGNAL PROTEINS (help coordinate body's activities) RECEPTOR PROTEINS (embedded within cell membranes. Transmit nerve impulses) CONTRACTILE PROTEINS (found in muscle cells) STRUCTURAL PROTEINS (found in fibers that make up tendons and ligaments). Eg: Collagen. STORAGE PROTEINS (supply amino acids to developing embryos).

What does the function of the different proteins depend on?

Individual shapes.

Comment on the significance of protein shape. What are prions?

Particular amino acid chain folds spontaneously into the corresponding 3-d shape (protein) if in right chemical environment. Many diseases arise coz amino acid chains don't fold correctly. Eg: Parkinson's Eg: Alzheimer's Prions= infectious misshapen proteins associated with serious degenerative brain diseases. -Eg: Mad cow disease

What is a protein?

Polymer made of amino acid monomers.