Chapter 5 The Structure and Function of Macromolecules

Chapter 5 The Structure and Function of Macromolecules 3 themes are emphasized n. Hierarchy of structural levels n. Emergent properties n. Form fits function

Polymers n n Large molecules of many repeating subunits called monomers Monomers are joined by removing a water molecule. (condensation reaction or dehydration reaction) Hydrolysis-addition of water and breaking of polymers into smaller units 40 -50 monomers

Classes of Polymers n n Carbohydrates Lipids Proteins Nucleic Acids

Carbohydrates n n Monomers called monosaccharides Cellular use: energy, energy storage, structure (C, 2 H, O)n Monosaccharides, disaccharides, and polysaccharides

Monosaccharides n n Glucose, fructose and galactose Aldehydes and ketones 3 -7 carbons/molecule Linear and ring forms (form rings in aqueous solutions)

Disaccharides sucrose, lactose and maltose n n 2 monosaccharides, sucrose = glucose+fructose Joined by a dehydration reaction

Polysaccharides n n n Several hundred or more monosaccharides Energy storage: starch and glycogen Structural: cellulose and chitin https: //www. youtube. com/watch? v=E 1 Wt 4 -O_X 9 U&app=desktop

http: //video. about. com/chemistry/How-to-Make-Slime. htm

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Lipids n n Diverse group (phospholipids, triglycerides, steroids, waxes) Many functions: energy storage, structure, regulation, buoyancy, cushioning, insulation C, H, and O High proportion of H

Triglycerides n n Glycerol + 3 fatty acids Linked by ester linkage (dehydration synthesis) Oils and fats Saturated vs. unsaturated?

Why soap works (and stops working)

Phospholipids n n Subunit of ALL cell membranes 2 fatty acids + phosphate group + glycerol = phospholipid

Steroids n n n At least 4 interlocking rings Regulatory molecules Cholesterol-precursor of many steroids Cholesterol is a component of cell membranes Cholesterol can contribute to atherosclerosis

Cholesterol is a steroid Found in the cell membrane can serve as chemical messengers

Proteins • • • Monomers called amino acids 20 different amino acids Joined by peptide linkage Function as support, storage, transport, signaling, defense, movement, and catalysts C, H, O, N, S Make up 50% of cellular DRY weight

n n n On June 6, 1822, an employee of the American Fur Company on Mackinac Island, named Alexis St. Martin, was accidentally shot in the stomach Dr. Beaumont treated his wound, but expected St. Martin to die from his injuries It healed (forming a fistula) He lived and in 1825 Beaumont conducted digestion experiments on him.

Amino Acid Structure n n Contains 3 functional groups Amino, carboxyl and R groups Grouped according to the R group Polar, nonpolar, charged and uncharged

n The portion of each amino acid that is different is a side chain called an R-group. Some R-groups are acidic and some are basic. Some are polar and some are nonpolar.

Four Levels of Protein Organization n n n Primary Secondary Tertiary Quaternary Achieves 3 D shape spontaneously, not predictable Denaturation

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Nucleic Acids n n Monomers are nucleotides Condensation linkage is called a phosphodiester linkage 2 types: RNA and DNA Function: 1) control heredity 2) control cell functions

Nucleotides n n n 3 parts: 5 -C sugar, phosphate and nitrogenous base 2 types of sugars: ribose and deoxyribose 2 types of nitrogenous bases: purines and pyrmidines

Purines and Pyrmidines n n Purines: 1) adenine and guanine 2) double ring structure Pyrimidines: 1) thymine, uracil, and cytosine 2) single ring

Other n Hybrid molecules n n Lipoproteins, glycolipids, and glycoproteins Form ECM (extra cellular matrix)