Structure & Function of Carbohydrates :Structure & Function of Carbohydrates Dr. Deryck D. Pattron, Ph.D.


Carbohydrates :Carbohydrates Carbohydrates consist of the elements carbon (C), hydrogen (H) and oxygen (O) with a ratio of hydrogen twice that of carbon and oxygen.


Carbohydrates :Carbohydrates 40% and 60% of total calories should come from complex carbohydrates (starches) and naturally occurring sugars.


Carbohydrates :Carbohydrates Carbohydrates include sugars, starches, cellulose and many other compounds found in living organisms. In their basic form, carbohydrates are simple sugars or monosaccharides.


Carbohydrates :Carbohydrates These simple sugars can combine with each other to form more complex carbohydrates. The combination of two simple sugars is a disaccharide.


Carbohydrate :Carbohydrate Carbohydrates consisting of two to ten simple sugars are called oligosaccharides, and those with a larger number are called polysaccharides.


Monosaccharides :Monosaccharides Classified by the number of carbons in the saccharide unit. Triose (3-carbons). Tetrose (4-carbons). Pentose (5-carbons) e.g. fructose. Hexoses (6-carbons) e.g. glucose and galactose.


Disaccharide :Disaccharide Two monosaccharides linked together E.g. sucrose or table sugar E.g. lactose = glucose + galactose E.g. maltose = glucose + glucose


Oligosaccharide :Oligosaccharide Three-ten monosaccharides linked together Raffinose (3 carbon) Stachyose (4 carbon)


Polysaccharides :Polysaccharides Many monosaccharides linked together in long chains Starch Glycogen Fiber Cellulose Chitin


Polysaccharide :Polysaccharide


Branched Polysaccharide :Branched Polysaccharide Branched: storage of energy starch - energy storage in plants (wheat, potatoes) glycogen - energy storage in animals (liver, muscle)


Linear Polysaccharide :Linear Polysaccharide Linear: structural material cellulose - found in cotton, plant cell walls. chitin-found in the exoskeleton of insects.


Cellulose Molecular Structure :Cellulose Molecular Structure


Cellulose Structure :Cellulose Structure


Function of Carbohydrates :Function of Carbohydrates Supplies energy-body, brain and the nervous system Source of carbon in metabolic processes Storage form of energy Structural elements of cells and tissues


Side effects of Carbohydrates :Side effects of Carbohydrates Excessive carbohydrates can cause an increase in the total caloric intake, causing obesity and pancreatic cancer in women. Deficient carbohydrates can cause a lack of calories (malnutrition), or excessive intake of fats to make up the calories. Low-fat, high-carbohydrate diets contribute to hyperinsulinemia and hypertriglyceridemia.


References :References Harper, A. (1999). "Defining the Essentiality of Nutrients." In Modern Nutrition in Health and Disease, 9th edition, ed. M. E. Shills, et al. Baltimore, MD: Williams and Wilkins. Morrison, Gail, and Hark, Lisa (1999). Medical Nutrition and Disease, 2nd edition. Cambridge, MA: Blackwell Science. Subar, A. F., et al. (1998). "Dietary Sources of Nutrients in the U.S. Diet, 1989 to 1991." Journal of the American Dietetic Association 98:537. Wardlaw, Gordon M., and Kessel, Margaret (2002). Perspectives in Nutrition, 5th edition. Boston: McGraw-Hill.


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