Carbohydrates, proteins, lipids, and nucleic acids macromolecules

Organic compound contain carbon Carbohydrates  Contain elements: hydrogen, oxygen, and carbon  Hydrogen and oxygen are found in the same ratio as water 2:1

Three types of carbohydrates: 1. Monosaccharides (simple sugars)  Glucose, fructose, galactose  Have same molecular formula C 6 H 12 O 6  Differ in their structural formulas

Disaccharides  Two simple sugars joined together by dehydration synthesis  Sucrose, maltose  Have same formula C 12 H 22 O 11

Polysaccharides  Hundreds of simple sugars bonded together  Cellulose (supporting material found in cell walls of plant cells)  Starch (plant storage of sugar)  Glycogen (animal storage of sugar, found in muscle and liver cells)

Dehydration synthesis (Condensation reaction) Building up of complex molecules from simpler molecules, with the release of water

Hydrolysis Reverse process, large molecules are broken down to their building blocks, with the addition of water

Polymer Collection of many similar, repeating units to form a large molecule

Lipids Fats, oils, and waxes, contain hydrogen, carbon, and oxygen Typically consists of a glycerol molecule bonded to 3 fatty acids known as a triglyceride Formed by dehydration synthesis

Saturated fats Role in heart disease Have animal origins Butter, lard, whole milk, and milk products Solid at rm temp Saturated with hydrogen atoms which are attached to each of the carbon atoms

Unsaturated fats Have at least one carbon to carbon double bond Missing hydrogen atoms Liquid at rm temp Plant oils such as corn oil, olive oil, sunflower oil, and fish oils

Proteins Contain carbon, hydrogen, oxygen, and nitrogen and in many instances, sulfur Large polymers of many repeating amino acid units 20 different types of amino acids More than 3,000 amino acids in a protein

Bond between amino acids is called a peptide bond A chain of amino acids is a polypeptide Shape of protein molecule itself depends on the nature of the attraction between the different parts of the polypeptide chain Formed by dehydration synthesis

Polypeptide, not necessarily same as a protein Example Polypeptide would be a strand of yarn Protein would be a sweater

Shape of protein Sequence of amino acids determines proteins shape Shape determines how protein functions Function of protein depends on its ability to recognize and bind to some other molecules

4 levels of protein structure 1. Primary=sequence of covalently joined amino acids in a polypeptide (linear) 2. Secondary=bending and hydrogen bonding of a polypeptide to form helices and pleated sheets 3. Tertiary=overall shape of polypeptide 4. Quaternary=association between 2 or more polypeptides

Nucleic acids Contain carbon, hydrogen, oxygen, nitrogen, and phosphorus Largest organic molecules known Made up of thousands of repeating units called nucleotides

Nucleotides consist of three parts:  1. phosphate  2. a five carbon sugar (ribose or deoxyribose)  3. nitrogen base DNA plays key role in determination of heredity RNA important in the synthesis of protein

Enzymes Organic catalysts, they affect the rate of a chemical reaction w/out being changed Can be used over and over again Protein in nature and specific to their action Often work with coenzymes which are smaller and not protein, and are active only with enzymes  Example of coenzymes (B-complex vitamins)

How enzymes function: Enzymes are huge compared to the molecules on which they interact Only a small portion of the enzyme functions when it is active, called the active site The molecule on which the enzyme acts is called the substrate They work like a “lock and key” The name of the enzyme usually has the ending –ase, added to the stem of the word which is taken from the substrate  Examples: Enzyme Maltase; substrate Maltose “ Lipase; “ Lipids “ Protease; “ Protein

Factors affecting enzyme action: pH  Depends on enzyme; maltase functions best in a pH of 7; pepsin, found in the stomach at a pH of ; trypsin, in the small intestine, pH Temperature  Most function best at body temperature 37 0 C  Lower temp activity of enzyme decreases  As temp is raised activity increases until a maximum is reached at about 40 0 C; beyond this point enzyme becomes distorted and enzyme deactivation occurs Relative amounts of enzyme and substrate  Amt of enzyme increased, while substrate remains constant; rate of reaction is increased to a point; after that rate remains constant  Amt of substrate is increased, while concentration of enzymes remains the same; rate of reaction will increase and will continue up to the point where every available enzyme molecule is actively involved in the reaction