Carbohydrates G11 Humanities PDF

Carbohydrates G11 Humanities What Are Carbohydrates? ➔ Simple carbohydrates are substances composed of C,H,O. ➔ The most abundant carbohydrates contain six or multiples of six carbon atoms per molecule. ➔ Carbohydrates contain carbonyl group (aldehyde and ketone a...

Carbohydrates G11 Humanities What Are Carbohydrates? ➔ Simple carbohydrates are substances composed of C,H,O. ➔ The most abundant carbohydrates contain six or multiples of six carbon atoms per molecule. ➔ Carbohydrates contain carbonyl group (aldehyde and ketone and hydroxyl groups. C.B. Notes Role of Carbohydrates They are the most important organic substances that enter in the chemical composition of animals and plants. Carbohydrates polymers (repeated units) linked to proteins and lipids play an important role in the functioning of the organism. They are stored in the form of glycogen, that provide a short term energy reserve. Carbohydrate’s oxidation provide energy for the body. C.B. Notes  C.B. Carbohydrates are classified according to their Notes complexity into: Oligosaccharide 2-10 units 1 unit More than 10 units A- Monosaccharides C.B. Notes 1. One sugar unit (the simplest units of carbohydrates that cannot be broken down by hydrolysis) 2. Are white crystalline solids. 3. All carbon atoms are linked by simple bonds. 4. Soluble in water, insoluble in organic solvents (eg: ethanol). 5. Sweet taste 6. They can act as reducing sugars due to the presence of carbonygroup (aldose if aldehyde and ketose if ketone )  C.B. Common Monosaccharides Notes 1) Glucose (Glu) (dextrose) 2) Fructose (Fru: Levulose) 3) Galactose (Gal) *** They have the same molecular formula C6H12O6, but different structural formulas. Monosaccharide Properties M o no saccharid e Fro m Taste Glucose Fructose Galactose B- Oligosaccharides 1. They contain two to ten monosaccharide units. 2. Disaccharides = two monosaccharides (linked together by glycosidic linkage) 3. Monosaccharide + Monosaccharide Disaccharides + H2O  Disaccharides Disaccharides Properties Hydrolysis It is the major sugar found in milk. Lactose It is synthesized in the mammary Lactose → glucose + galactose gland. It is common table sugar. Sucrose It is produced commercially from Sucrose → glucose + fructose beets and cane sugar. It is produced during starch Maltose → glucose + glucose Maltose digestion in human body. Test for reducing sugars Chemistry - 3Sec - Using Fehling's solution to detect glucose (youtube.com) All monosaccharide ( glucose , fructose , galactose) and some disaccharides ( lactose and maltose ) are reducing sugars. Reducing sugar + fehling (blue solution) heat red brick precipitate. Sucrose + fehling solution heat no red brick precipitate. C- Polysaccharide ❏ It is a polymer that contains hundreds or thousands of monosaccharide units linked together by glycosidic linkages. ❏ Examples of polysaccharides: starch, cellulose, and glycogen. C- Polysaccharide ❏ Bond Linear (ex: cellulose- stored polysaccharide in plants) Branched (ex: Glycogen- stored polysaccharide in animals) Polysaccharides 1. Starch contains glucose units. It is found in plant tissues as banana and several legumes. 2. Glycogen is referred to as animal starch, for it is essential storage polysaccharide in animals. Liver and muscle cells are the storage sites for glycogen in animals. 3. Cellulose is the structural component of the cell wall of plants. It can’t be hydrolyzed in the human digestive tract because humans lack the enzyme. So it can’t be considered a source of nutrition for humans. It has favorable action on digestive transit helping in peristalsis. Iodine test Starch + iodine (reddish brown) dark blue color