Macromolecules GIANT MOLECULES Made up of thousands of

Macromolecules “GIANT MOLECULES” Made up of thousands of single organic molecules known as monomers. Formed by a process known as polymerization, in which large molecules are produced by joining small ones together. The small units (monomers), join together to form large units (polymers)

Usually consist of many repeating units Large in size Some examples: Category Example Subunit(s) Lipids Fat (trigylceride) Glycerol & fatty acids Carbohydrates Polysaccharide Monosaccharide Proteins Polypeptide Amino acid Nucleic Acids DNA, RNA Nucleotide

Carbohydrates, Lipids & Proteins Simple molecules built by covalent bonding and addition of functional groups. Biological polymers built of simple molecules Assembled and disassembled in very similar reactions; condensation and hydrolysis

Carbohydrates As the name implies, consist of carbon, hydrogen, and oxygen The basic formula for carbohydrates is CH 2 O, meaning that there is one carbon atom, two hydrogen atoms, and one oxygen atom as the ratio in the structure of carbohydrates What would be the formula for a carbohydrate that has 3 carbons? C 3 H 6 O 3

Condensation and Hydrolysis Condensation - Removal of water molecule Used to connect monomers together to make polymers Polymerization of glucose monomers to make starch Hydrolysis - Addition of water molecule Used to disassemble polymers into monomer parts Digestion of starch into glucose monomers Specific enzymes required for each reaction Accelerate reaction Are not used in the reaction (catalysts) What are the main difference between an inorganic catalyst and biological catalyst? This we will discover!

Synthesis and Degradation of Polymers

Monosaccharides: Single sugar molecules, commonly known as ‘simple sugars’ Appear as white crystals that are soluble and sweet to taste Examples Glucose (blood), Fructose (fruit, honey) & Galactose (does not occur naturally) Hexoses - Six carbon atoms. Isomers of C 6 H 12 O 6 Ribose and deoxyribose (in nucleotides) Pentoses – Five carbon atoms. C 5 H 10 O 5 and C 5 H 10 O 4

Disaccharides: Monosaccharide molecules react to form disaccharides – condensation/ dehydration/ elimination reaction (all refer to same reaction type) Also soluble (due to presence of polar OH groups) and sweet to taste Examples: Sucrose Table sugar, maple sugar One glucose and one fructose molecule joined by dehydration Maltose Malt sugar Two glucoses joined by dehydration

Common Monosaccharides, Disaccharides & Polysaccharides

Synthesis = condensation synthesis (can also be called dehydration) Removal of OH + H forms water, H 2 O Ether link (or glycosidic link) -O- formed in disaccharide.

Glycosidic Linkages in Carbohydrates Water eliminated 11

Disassembly = hydrolysis Bond between monosaccharide units is broken when reacted with water. The OH- + H+ ions fill the ether bonding sites.

Polysaccharides Build up of more than two monosaccharide units by condensation Again can be disassembled by hydrolysis.

Polysaccharides Polymers of monosaccharides Low solubility (non polar); not sweet to taste Examples: Glycogen Stored fuel in liver, muscle cells Polymer of glucose, unbranched Used for short-term energy storage (digestible by hydrolysis) Starch Polymer of glucose Plant equivalent of glycogen Used for short-term energy storage (digestible by hydrolysis) Often branched chain Amylose, corn starch

More polysaccharide examples Cellulose Long, coiled polymer of glucose Very large linear polymer that form bundles Glucoses connected differently than in starch Note the different orientations of the –CH 2 OH groups on adjacent glucose monomers above on starch (top) and cellulose (bottom) monomers. Alternating sides in cellulose polymer. Structural element for plants Main component of wood and many natural fibers Indigestible by most animals Chitin Polymer of glucose Each glucose with an amino group Very resistant to wear and digestion (indigestible) Arthropod exoskeletons, cell walls of fungi

Starch Structure and Function

Glycogen Structure and Function

Cellulose Structure and Function

Lipids Insoluble in water Long chains of repeating CH 2 units Renders molecule Non Polar Types of Lipids Type Organism Uses Human Uses Fats Oils Long-term energy storage & thermal insulation in animals Long-term energy storage in plants and their seeds Phospholipids Component of plasma membrane No-stick pan spray Steroids Component of plasma membrane; Medicines hormones Butter, lard Cooking oils

Lipids Larger group, mainly constructed of C and H, some O Fats (Triglycerides) mostly “saturated” fatty acids (single carbon bonds), unreactive & solid at room temperature 1 glycerol, 3 fatty acids Oils “unsaturated” fatty acids, liquid at room temperature 1 glycerol, 3 fatty acids

Lipids Steroids unlike other lipids, 4 -ring structure Phospholipids 1 glycerol molecule + 2 fatty acids (not three like fats & oils) + 1 phosphate-containing acid

Types of Lipids: Triglycerides (Fats) Long-term energy storage Assembled of glycerol + 3 fatty acids by condensation synthesis. Backbone of one Glycerol molecule = 3 -carbon chain with 3 hydroxyl groups (OH-) Fatty acid = long carbon backbone with Carboxylic acid at one end Carboxylic acid connects to –OH on glycerol in condensation reaction Three fatty acids attached to each glycerol molecule

Synthesis = condensation Remove H from glycerol and OH from fatty acids Creates ester linkage