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Introduction to Carbohydrate Unit. 1. What is the predominant monosaccharide in carbohydrates?. Glucose, also referred to as dextrose. #s 2-4. “Di” = 2; two monosaccharide units Oligo: 3-10 monosaccharide units Poly: >10 monosaccharide units.
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1. What is the predominant monosaccharide in carbohydrates? • Glucose, also referred to as dextrose
#s 2-4 • “Di” = 2; two monosaccharide units • Oligo: 3-10 monosaccharide units • Poly: >10 monosaccharide units
#5 What is a common suffix for [specific] carbohydrates? List common carbohydrates • -Ose • Saccharide: derived from the Greek sakchar, meaning sugar or sweetness
#5 Specific examples of carbohydrates • Monosaccharides • Examples: glucose (C6H12O6), fructose, and galactose, ribose • Disaccharides • Examples: sucrose, lactose, and maltose
#5 Specific examples of Carbohydrates • Oligosaccharides: 3-10 sugars • Raffinose and stachyose • Polysaccharides • Examples: starch, pectin, cellulose, and glycogen • Sugar alcohols • Sorbitol, xylitol
#6 & #9: What is the name of the reaction by which di-, oligo-, and polysaccharides are formed? What is the name of the bonds between carbohydrates monomers? • Dehydration synthesis/condensation • (#9 )This type of rxn forms a glycosidic bond (C-O-C) also called glycosidic linkage • Two forms: alpha and beta
10. How do alpha and beta glycosidic bonds differ and how can this affect digestion? • Alpha differs from the beta glycosidic bond only in the angle of formation between the two sugars • Alpha-glycosidic linkage is below the plane of the rings and the beta glycosidic linkages are above • Humans lack enzymes needed to cleave beta-glycosidic linkages – lactose intolerance
16. Why are oligosaccharides "gassy"? • Can’t be broken down in small intestine and become “food” for bacteria of large intestine • Bacterial metabolism of oligosaccharides results in gas byproducts
7. What is the name of the reaction by which di-, oligo-, and polysaccharides are broken down? • Hydrolysis • The addition of a water molecule across a bond • The breaking down of a chemical compound into two or more simpler compounds by reacting with water. • http://nhscience.lonestar.edu/biol/dehydrat/dehydrat.html
#8 – Summarize the relationship between dehydration synthesis and hydrolysis • They are reverse rxns, where one is a synthesis rxn and one is a break down rxn Hydrolysis Dehydration Synthesis Disaccharide + H20 MonoSach + MonoSach
11. In your own words, describe how/why cyclic carbohydrates form.
12. How are carbohydrates found in humans classified? 6 • By number of carbons • Trisoses • Pentoses • Hexoses • Septoses…. 5
13. Carbs are also classified by their functional groups - what are the names of these classifications? • Aldoses – contain aldehyde functional group • Terminal carbonyl C=O • Ketoses – contain ketone functional group • Internal carbonyl Carbonyl carbon
Carbonyl Carbon • In the closed-ring (cyclic) structure, the carbonyl carbon is the one which is attached to the O of the ring and an OH group
14. Where can your body storage glucose? • Liver as glycogen • Smaller amounts in muscles and brain as glycogen • Circulates in blood stream in very specific range
15. What are indigestible forms of polysaccharides known as? • Dietary fiber
17. Explain the basic relationship between sugar and diabetes. • Insulin: pancreatic hormone which signals cells to uptake glucose from blood (into cells) • People with Diabetes either do not produce insulin or do not respond to insulin that is present
18. How does the glycemic index classify carbohydrates? • By how quickly and how high a specific carbohydrate boosts blood glucose levels compared to pure glucose
19. List food sources of carbohydrates • Grains (breads, rice, pasta, cereal) • Fruit • Dairy • Beans, legumes • Soda, candy, etc.
20. List some functions of carbohydrates: • Energy source for cells; primary for brain • Protein sparing • Breakdown of fats and preventing ketosis • Biological recognition • *Dietary fiber & digestive health • *Flavor and sweeteners