Chapter 5 Macromolecules Macromolecules A large molecule in

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Chapter 5: Macromolecules

Chapter 5: Macromolecules

Macromolecules • A large molecule in a living organism – Proteins, Carbohydrates, Nucleic Acids

Macromolecules • A large molecule in a living organism – Proteins, Carbohydrates, Nucleic Acids • Polymer- long molecules built by linking repeating building blocks in a chain • Monomer- units that serve as building blocks of polymer

Dehydration Synthesis - How cells link together monomers - Monomers have H atoms and

Dehydration Synthesis - How cells link together monomers - Monomers have H atoms and hydroxyl groups - Add a monomer to a chain, a water molecule is released

Hydrolysis - Opposite of dehydration synthesis - Bond in a polymer are broken by

Hydrolysis - Opposite of dehydration synthesis - Bond in a polymer are broken by addition of water

1. Carbohydrates: include sugars and polymers of sugar Monosaccharides: the simplest carbohydrate, made of

1. Carbohydrates: include sugars and polymers of sugar Monosaccharides: the simplest carbohydrate, made of a single sugar

Monosaccharides • The simplest carbohydrate made of a single sugar • Have molecular formulas

Monosaccharides • The simplest carbohydrate made of a single sugar • Have molecular formulas multiple of CH 20 (Most common sugar is glucose C 6 H 1206) • Have a hydroxyl group (OH) and a carbonyl group (C=0) • OH group make it an alcohol and the C=0 make it an aldehyde or ketone

Fig. 5 -3 Aldoses Trioses (C 3 H 6 O 3) Pentoses (C 5

Fig. 5 -3 Aldoses Trioses (C 3 H 6 O 3) Pentoses (C 5 H 10 O 5) Hexoses (C 6 H 12 O 6) Glyceraldehyde Ribose Ketoses Glucose Galactose Dihydroxyacetone Ribulose Fructose

Monosaccharides (cont’d) • Most sugars end in -ose • Though often drawn as linear

Monosaccharides (cont’d) • Most sugars end in -ose • Though often drawn as linear skeletons, in aqueous solutions many sugars form rings • Monosaccharides serve as a major fuel for cells (glucose)

Disaccharide • A double sugar created when dehydration synthesis joins Ex: 2 glucose ->

Disaccharide • A double sugar created when dehydration synthesis joins Ex: 2 glucose -> maltose (malt sugar makes beer) • Glycosidic linkage: covalent bond between 2 sugars of a disaccharide

1– 4 glycosidic linkage Glucose Maltose (a) Dehydration reaction in the synthesis of maltose

1– 4 glycosidic linkage Glucose Maltose (a) Dehydration reaction in the synthesis of maltose 1– 2 glycosidic linkage Glucose Fructose (b) Dehydration reaction in the synthesis of sucrose Sucrose

Polysaccharide • Hundreds or thousands of monosaccharides joined together (glycosidic links) • Many act

Polysaccharide • Hundreds or thousands of monosaccharides joined together (glycosidic links) • Many act as storage molecules of sugar, that cells break down for energy

Polysaccharide- Starch • Made of all glucose and found in plants • Plants store

Polysaccharide- Starch • Made of all glucose and found in plants • Plants store starch and break into glucose when needed for energy • Humans and animals hydrolyze starch when they eat it (found in wheat, corn, rice, potatoes)

Fig. 5 -6 Chloroplast Mitochondria Glycogen granules Starch 0. 5 µm 1 µm Glycogen

Fig. 5 -6 Chloroplast Mitochondria Glycogen granules Starch 0. 5 µm 1 µm Glycogen Amylose Amylopectin (a) Starch: a plant polysaccharide (b) Glycogen: an animal polysaccharide

Polysaccharide- Glycogen • Excess sugar in animals is stored as glycogen in liver and

Polysaccharide- Glycogen • Excess sugar in animals is stored as glycogen in liver and muscles • Glycogen is hydrolyzed to release glucose when needed

Polysaccharide- Cellulose • A component of a plant’s cell wall, gives them structure •

Polysaccharide- Cellulose • A component of a plant’s cell wall, gives them structure • Glycogen is hydrolyzed to release glucose when needed • A polymer of glucose, but the glycosidic linkages differ. • Cellulose molecules connected by hydrogen bonds and form fiber

Fig. 5 -9

Fig. 5 -9

1 -4 linkage of alpha glucose molecules 1 -4 linkage of beta glucose molecules

1 -4 linkage of alpha glucose molecules 1 -4 linkage of beta glucose molecules

 • Chitin, another structural polysaccharide, is found in the exoskeleton of arthropods •

• Chitin, another structural polysaccharide, is found in the exoskeleton of arthropods • Chitin also provides structural support for the cell walls of many fungi Copyright © 2008 Pearson Education, Inc. , publishing as Pearson Benjamin Cummings

Fig. 5 -10 (a) The structure of the chitin monomer. (b) Chitin forms the

Fig. 5 -10 (a) The structure of the chitin monomer. (b) Chitin forms the exoskeleton of arthropods. (c) Chitin is used to make a strong and flexible surgical thread.

Lipid • Compounds that consist mainly of C and H atoms linked by nonpolar

Lipid • Compounds that consist mainly of C and H atoms linked by nonpolar covalent bonds What does this say about their solubility? • Ex: fats, oils, waxes

Fats • A large lipid made of glycerol and fatty acids - a 3

Fats • A large lipid made of glycerol and fatty acids - a 3 carbon alcohol with hydroxyl group • Ex: fats, oils, waxes • 1 fat molecule = 1 glycerol and 3 fatty acids • Function is energy storage (1 g of fat stores more than 2 x as much energy as 1 g of starch)

Fig. 5 -11 Fatty acid (palmitic acid) Glycerol (a) Dehydration reaction in the synthesis

Fig. 5 -11 Fatty acid (palmitic acid) Glycerol (a) Dehydration reaction in the synthesis of a fat Ester linkage (b) Fat molecule (triacylglycerol)

Saturated Fats • No double bond in fatty acid • Solids (lard, butter- animal

Saturated Fats • No double bond in fatty acid • Solids (lard, butter- animal fats) • Leads to heart disease, plaque in blood vessels

Unsaturated Fats • the fatty acid contains double bonds, preventing the skeleton from having

Unsaturated Fats • the fatty acid contains double bonds, preventing the skeleton from having the max # of hydrogen’s. • Molecules can’t pack together tightly and form liquids at room temp (oils and plant fats)

 • A diet rich in saturated fats may contribute to cardiovascular disease through

• A diet rich in saturated fats may contribute to cardiovascular disease through plaque deposits • Hydrogenation is the process of converting unsaturated fats to saturated fats by adding hydrogen • Hydrogenating vegetable oils also creates unsaturated fats with trans double bonds • These trans fats may contribute more than saturated fats to cardiovascular disease Copyright © 2008 Pearson Education, Inc. , publishing as Pearson Benjamin Cummings

Phospholipids • Major component of cell membranes • Similar to fat, but contain phosphorus

Phospholipids • Major component of cell membranes • Similar to fat, but contain phosphorus and have a fatty acid (not 3)

Waxes • 1 fatty acid an alcohol • More hydrophobic than fats • Natural

Waxes • 1 fatty acid an alcohol • More hydrophobic than fats • Natural coating on fruit • Insects have to keep from drying out

Steroids • lipids whose carbon skeleton is bent to form 4 fused rings •

Steroids • lipids whose carbon skeleton is bent to form 4 fused rings • all steroids have 3 -6 sided rings and 15 sided ring • Ex: cholesterol found in animal cell membranes and animal cells use it to make other steroids (estrogen and testosterone)

Fig. 5 -15

Fig. 5 -15