The Structure and Function of Macromolecules
I. Polymers What is a polymer? Poly = many; mer = part. A polymer is a large molecule consisting of many smaller sub-units bonded together. What is a monomer? A monomer is a sub-unit of a polymer.
II. Classes of Organic Molecules: What are the four classes of organic molecules? Carbohydrates Lipids Proteins Nucleic Acids
Carbohydrates Sugars Carbo = carbon, hydrate = water; carbohydrates have the molecular formula (CH 2 O) n Functions: Store energy in chemical bonds Glucose is the most common monosaccharide Glucose is produced by photosynthetic autotrophs
1. Structure of Monosaccharides An OH group is attached to each carbon except one, which is double bonded to an oxygen (carbonyl).
Classified according to the size of their carbon chains, varies from 3 to 7 carbons. Triose = 3 carbons Pentose = 5 carbons Hexose = 6 carbons
Many monosaccharides form rings:
2. Structure of Disaccharides Double sugar that consists of 2 monosaccharides
Examples of Disaccharides: Lactose = glucose + galactose Sucrose = glucose + fructose
3. Polysaccharides Structure: Polymers of a few hundred or a few thousand monosaccharides. Functions: energy storage molecules or for structural support:
Starch is a plant storage from of energy, easily hydrolyzed to glucose units Cellulose is a fiber-like structureal material - tough and insoluble - used in plant cell walls Glycogen is a highly branched chain used by animals to store energy in muscles and the liver. Chitin is a polysaccharide used as a structural material in arthropod exoskeleton and fungal cell walls.
Lipids Structure: Greasy or oily nonpolar compounds Functions: Energy storage cell membrane structure Protecting against drying out. Insulating against cold. Absorbing shocks. Regulating cell activities by hormone actions.
1. Structure of Fatty Acids Long chains of mostly carbon and hydrogen atoms with a -COOH group at one end. When they are part of lipids, the fatty acids resemble long flexible tails.
Saturated and Unsaturated Fats Unsaturated fats : liquid at room temp one or more double bonds between carbons in the fatty acids allows for kinks in the tails most plant fats Saturated fats: have only single C-C bonds in fatty acid tails solid at room temp most animal fats
Saturated fatty acid Unsaturated fatty acid
2. Structure of Triglycerides Glycerol + 3 fatty acids
3. Phospholipids Structure: Glycerol + 2 fatty acids Function: Main structural component of cell membranes, where they arrange in bilayers.
Phospholipids in Water
4. Waxes Function: Lipids that serve as coatings for plant parts and as animal coverings.
5. Steroids Structure: Four carbon rings with no fatty acid tails Functions: Component of animal cell membranes Modified to form sex hormones
Proteins Structure: Polypeptide chains Consist of peptide bonds between 20 possible amino acid monomers Have a 3 dimensional globular shape
1. Functions of Proteins Enzymes which accelerate specific chemical reactions up to 10 billion times faster than they would spontaneously occur. Structural materials, including keratin (the protein found in hair and nails) and collagen (the protein found in connective tissue).
Specific binding, such as antibodies that bind specifically to foreign substances to identify them to the body's immune system. Specific carriers, including membrane transport proteins that move substances across cell membranes, and blood proteins, such as hemoglobin, that carry oxygen, iron, and other substances through the body.
2. Structure of Amino Acid Monomers Consist of an asymmetric carbon covalently bonded to: Hydrogen Amino group Carboxyl (acid) group Variable R group specific to each amino acid
Nucleic Acids Two kinds: DNA: Deoxyribose Nucleic Acid double stranded can self replicate makes up genes which code for proteins is passed from one generation to another RNA: Ribose Nucleic Acid single stranded functions in actual synthesis of proteins coded for by DNA is made from the DNA template molecule
1. Nucleotide Structure Both DNA and RNA are composed of nucleotide monomers. Nucleotide = 5 carbon sugar, phosphate, and nitrogenous base Deoxyribose in DNA Ribose in RNA
DNA: Double helix 2 polynucleotide chains wound into the double helix Base pairing between chains with H bonds A - T C - G
Summary of the Organic Molecules: