Structure and Function of Macromolecules

Monomers, Polymers, and Macromolecules Macromolecules: groups of polymers covalently bonded – 4 classes of organic macromolecules to be studied: 1. Carbohydrates 3. Proteins 2. Lipids 4. Nucleic Acids Monomers: repeating units that serve as building blocks for polymers Polymers: long molecule consisting of many similar or identical building blocks linked by covalent bonds

How do the monomers link up or break back into monomers? Condensation reaction (specifically, dehydration synthesis) two molecules covalently bond lose a water molecule in the process (THIS TAKES ENERGY TO DO!!!) Hydrolysis polymers are disassembled to monomers by adding a water molecule back (ex. Digestion of food)

Organic Compounds and Building Blocks Carbohydrates – made up of linked monosaccharides Lipids -- CATEGORY DOES NOT INCLUDE POLYMERS (grouping based on insolubility) *Triglycerides (glycerol and 3 fatty acids) *Phospholipids *Steroids Proteins – made up of amino acids Nucleic Acids – made up nucleotides

Carbohydrates

Carbohydrates – fuel and building material Exist as three types: 1. monosaccharides (mono = 1)(Simple Sugars) 2. disaccharides (di = 2) (double sugars) 3. polysaccharides (poly = many) (complex sugars Made up of C, H, and O Names end in –ose Size of “carbon skeleton” determines category

Monosaccharides Are major sources of energy for cells Ex. Glucose made during photosynthesis (cellular respiration converts glucose to energy for our bodies) Most common: glucose, fructose, galactose

Figure 5.3 The structure and classification of some monosaccharides

Glucose, Fructose, Galactose Glucose: *made during photosynthesis *main source of energy for plants and animals Fructose: *found naturally in fruits *sweetest of monosaccharides Galactose: *found in milk *is usually in association with glucose or fructose

Diaccharide Disaccharide – two monosaccharides bonded together with the release of water. (double sugar) Ex: table sugar (Sucrose)and lactose (sugar in milk) These must be broken down by the enzymes in our stomach to be utilized by the body.

Figure 5.5 Examples of disaccharide synthesis

Polysaccharide Polysaccharide – many monomers bonded together (12 or more) complex carbohydrate – the best type to eat Ex: Glycogen (plant starches, storage form of glucose) Starch (pasta, bread) Cellulose (Plant fiber which is good for you digestion – our bodies can’t break it down so it just passes through to help cleanse the colon.)

Figure 5.7b,c Starch and cellulose structures

Chemical Identification of Carbohydrates Benedict’s Test: Identifies the presence of a MONOSACCHARIDE by changing from blue to orange in the presence of heat Iodine Test : Identifies the presence of a POLYSACCHARIDE by changing from yellow to purple/black Process of Elimination: If there is no reaction with either the Benedict’s or Iodine Tests, then a DISACCHARIDE is present.