Carbohydrates HW 1-2

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

Figure 5.3 The structure and classification of some monosaccharides

Figure 5.3x Hexose sugars Glucose Galactose

Figure 4.6 Three types of isomers

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.

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

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

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

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

Figure 5.5 Examples of disaccharide synthesis HW 1-3 Link to disaccharides

Lactose

Polysaccharides – polymers linked by glycosidic bonds Polysaccharides – polymers linked by glycosidic bonds. Typically 100’s or 1000’s of monomers in length Polysaccharides are formed by linking monomers together IMPORTANT GLUCOSE POLYMERS PLANTS ANIMALS PLANTS α-GLUCOSE α-GLUCOSE β-GLUCOSE STARCH GLYCOGEN CELLULOSE AMYLOSE AMYLOPECTIN

Figure 5.7b,c Starch   PLANTS Link to polysaccharides

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

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

Figure 5.8 The arrangement of cellulose in plant cell walls Link to cellulose

Cellulose is passed through undigested in humans

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

PLANTS ANIMALS ENERGY STORAGE MOLECULES: PLANTS AND ANIMALS Fig. 5-6 ENERGY STORAGE MOLECULES: PLANTS AND ANIMALS Chloroplast Starch Mitochondria Glycogen granules 0.5 µm 1 µm Amylose Glycogen 20-30% ; more resistant to digestion; more compact structure, better for long term energy storage Amylopectin Water soluble, easily digested (b) Glycogen: an animal polysaccharide (a) Starch: a plant polysaccharide PLANTS ANIMALS

STARCH FORMS: Amylose vs. Amylopectin IB MEMORIZE LIST AMYLOSE: 20-30% of starch; more resistant to digestion; more compact structure, better for long term energy storage AMYLOPECTIN: 70-80% of starch; Water soluble, easily digested, better short-term energy

Amylose and Amylopectin Link to formation of starch Link to amylose form of starch Link to amylopectin form of starch 1-6 BRANCHES ≈ EVERY 30 GLUCOSE MOLECULES; LONG BRANCHES

Glycogen (energy storage animals) 1 -6 branches ≈ every 10 glucose molecules; numerous relatively short branches Link to glycogen

Comparison of Cellulose vs Starch vs Glycogen Amylopectin 1,6 Branches ≈ every 30 glucose; often longer branches Glycogen 1,6 Branches ≈ every 10 glucose (shorter branches) Comparison of Cellulose vs Starch vs Glycogen

Link to amylose form of starch Link to amylopectin form of starch Link to glycogen Link to cellulose Link to formation of starch