4 CLASSES OF MACROMOLECULES  Carbohydrates (sugars)  Lipids (fats)  Nucleic Acids  Proteins

Fig. 5-UN2

Fig. 5-UN2a

Fig. 5-UN2b

Carbohydrates, proteins and nucleic acids can form chainlike molecules called POLYMERS.  Polymers are formed by small, repeating units called monomers linked by covalent bonds

Figure 5.2 The synthesis and breakdown of polymers

Uses of Sugars in Cells Fuel – Energy source e.g. Combustion of glucose during cellular respiration Source of carbon (Building blocks) for molecules such as DNA

IB Carbohydrate Memorize List Disaccharides – maltose, lactose, sucrose – be able to recognize as disaccharides Be able to draw: ribose, α- glucose, and β-glucose

Monomers can be connected in various combinations like the 26 letters in the alphabet can be used to create a great diversity of words. DEER vs. REED same letters, different arrangement, different meanings 2. An immense variety of polymers can be built from a small set of monomers Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Figure 5.3 The structure and classification of some monosaccharides

Figure 5.3x Hexose sugars Glucose Galactose

Importance of Molecular Shapes  Our universe is three-dimensional – true properties of molecules can only be understood by looking at actual arrangements of molecules in space.  Example application: Chiral molecules – most drugs contain a carbon bonded to 4 different other atoms or groups of atoms.

Figure 4.6 Three types of isomers

In 2-D molecules look identical, in 3-D they are not.  Link to chiral molecules Link to chiral molecules Link to chiral molecules In 2-D, It looks as though the left structure can be converted into the right by rotating 180 o. In 3-D, we can see that these 2 molecules are actually mirror images of each other and are not identical.

Chiral Molecules – binding surfaces in your body recognize one arrangement but not the other

Figure 4.7 The pharmacological importance of enantiomers

Thalidomide – 1 form of drug treats morning sickness, the other causes mutations Effect of thalidomide mutations

Figure 5.4 Linear and ring forms of glucose While often drawn as a linear skeleton, in aqueous solutions monosaccharides form rings

Link to glucose animation Link to glucose animation

Figure 5.5 Examples of disaccharide synthesis

Link to disaccharides Link to disaccharides  Link to alpha – beta forms Link to alpha – beta forms Link to alpha – beta forms

Figure 5.7a Starch and cellulose structures Figure 5.7a Starch and cellulose structures IB MEMORIZE: RING FORMS Link to alpha beta forms

Figure 5.7x Starch and cellulose molecular models  Glucose  Glucose Starch Cellulose

Link to glucose animation Link to glucose animation

Figure 5.7b,c Starch and cellulose structures

Fig. 5-6 (b) Glycogen: an animal polysaccharide Starch Glycogen Amylose Chloroplast (a) Starch: a plant polysaccharide Amylopectin Mitochondria Glycogen granules 0.5 µm 1 µm ENERGY STORAGE MOLECULES (IB Amlyose vs Amplopectin) PLANTSANIMALS 20-30% - more resistant to digestion; more compact structure Water soluble, easily digested

Link to polysaccharides Link to polysaccharides  Link to amylose form of starch Link to amylose form of starch Link to amylose form of starch  Link to amylopectin form of starch Link to amylopectin form of starch Link to amylopectin form of starch  Link to cellulose Link to cellulose Link to cellulose

Figure 5.8 The arrangement of cellulose in plant cell walls

Figure 5.x1 Cellulose digestion: termite and Trichonympha COWS HAVE BACTERIA IN THEIR INTESTINAL TRACT THAT CAN BREAKDOWN CELLULOSE

Fig The structure of the chitin monomer. (a) (b) (c) Chitin forms the exoskeleton of arthropods. Chitin is used to make a strong and flexible surgical thread. CHITIN – A MODIFIED CARBOHYDRATE WITH STRONG AND FLEXIBLE PROPERTIES