MACROMOLECULES A Brief Review What are the 4 major macromolecules? How are they made or broken down? What are they made of? What are they used for?

Macromolecule Basics: “MACRO-” = LARGE large biological molecules “building blocks” for life 4 macromolecules: Carbohydrates Lipids Proteins Nucleic acids All but lipids are POLYMERS Polymer - a long molecule consisting of many similar building blocks (monomers) linked by covalent bonds Monomer – repeating units of a polymer ANALOGY = a train

How are macromolecules made and broken down? Synthesis = made Dehydration (condensation) reaction – 2 monomers are covalently bonded together through a LOSS of a WATER molecule Decomposition = broken down Hydrolysis (hydration) – covalent bonds between monomers are broken by the ADDITION of WATER Reverse of dehydration!

CARBOHYDRATES AKA: “sugars”, saccharides Serve as FUELS, sources of carbon, and structural support Composed of “CHO” Name ends in “-ose” 2 trademarks of sugars: a carbonyl group (>C=O) multiple hydroxide groups (-OH) GLUCOSE

CARBOHYDRATES Carbs can be classified by the number of monomers that comprise the sugar: Monosaccharides - “simple sugars” Examples: glucose; fructose; galactose Disaccharides – consists of 2 monosaccharides glucose + glucose = maltose glucose + fructose = sucrose Polysaccharides (“complex carbs”) – consists of many monosaccharides (usually more than 8) examples: starch or glycogen Reaction??

LIPIDS LARGE molecules that are not polymers! All are hydrophobic & consist mostly of hydrocarbons. Composed mostly of “CHO” Have less oxygen atoms than carbs. ? ?

Types of LIPIDS: 3 major groups: Triglycerides – “fats” & “oils” FUNCTIONS: long-term energy storage, protection, & insulation. Made up of: 1 glycerol – an alcohol AND 3 fatty acids – long C skeleton (of hydrocarbons) + a carboxyl group Saturated vs. unsaturated fats/oils? Phospholipids – Function: major component of cell membranes!!!! Structure: similar to triglycerides, but only has 2 fatty acid tails “TAIL” – nonpolar; hydrophobic 3 rd hydroxyl group is attached to a phosphate group “HEAD” – polar; hydrophilic Steroids – Structure: characterized by 4 fused rings of carbon skeletons Functions: regulate growth & development (hormones)

PROTEINS Account for approx. 50% of the dry mass of cells! Composed mostly of “CHON” Basic structure?? Proteins consist of one or more polypeptides folded and coiled into specific conformations (shapes). Polypeptides are polymers of amino acids. Amino acids  polypeptides  protein basic structure R = ?? Amine group? Carboxyl group?

The MANY Functions of Proteins! Structural support (collagen & elastin make connective tissues; keratin makes hair, feathers, & horns) Energy storage (ovalbumin-egg whites; casein-milk; plants & seeds) Transport of other substances (hemoglobin and red blood cells) Signaling within an organism (nerve cell transmission; insulin-regulates blood sugar) Movement (actin & myosin-muscle contraction) Defense against disease (antibodies) As ENZYMES: regulates metabolism (catalase-breaks down H 2 O 2 )

Nucleic Acids Composed mostly of “CHONP” Are composed of monomers called nucleotides. Each nucleotide contains: A nitrogenous base (N) A pentose (CHO) A phosphate group (P) 2 types of nucleic acids: Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA)