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Presentation on theme: "Carbohydrates."— Presentation transcript:

1 Carbohydrates

2 Discussion Questions: (Groups of 2 – 5 minutes!!!)
List some food items rich in carbohydrates. What is the difference between complex carbohydrates versus simple carbohydrates? Would you recommend a person who wants to lose weight to adopt a low-carb diet?

3 Canada’s Food Guide Carbohydrates make up the largest volume of our daily food Carbohydrates are found in: grain flour, cereals, pasta, potatoes and other vegetables, fruits, syrups, honey, candy, pop, juice, milk as well as in the pure crystalline form of our familiar table "sugar".

4 Functions of Carbohydrates
Energy source Plays a vital part in the digestion, metabolism, and oxidation of protein and fat. Too much carbohydrate = Glycogen in liver OR Fat

5 Simple versus Complex Carbohydrates
Simple Carbs: Quick source of energy (do not supply other nutrients or fiber) Quickly absorbed – rapid increase in blood sugar level followed by quick decline Small molecules (glucose, fructose, maltose, sucrose, lactose) Found in: fruit, fruit juice, table sugar, honey, soft drinks, and other sweets Complex Carbs: Supply energy and other nutrients and fiber Slowly digested – steady slow rise in blood sugar level Large molecules (starch and dietary fiber) Starch: breaks down into smaller carbs; supplies long, sustained energy to the body bread, cereal, potatoes, pasta, rice, and legumes (dried peas and beans) Dietary fiber: found in plant cells (non-digestible part of plants) tough and stringy it does not break down completely in the body Essential for regulating the body (digestion). bran, whole-grain foods, raw vegetables and fruit (especially the seeds and skins), legumes, nuts, seeds and popcorn

6 Some General Chemical Info
Hydrophilic organic molecule General formula (CH2O)n , n = number of carbon atoms for glucose, n = 6, so formula is C6H12O6 Names of carbohydrates word root sacchar- or the suffix -ose often used monosaccharide or glucose

7 Aldoses and Ketoses Aldoses contain the aldehyde group
Ketoses contain the ketone group

8 Ring Formation In aqueous solution, the aldehyde and ketone groups react with hydroxyl (-OH) group belonging to the same molecule

9 Monosaccharides Simplest carbohydrates General formula is C6H12O6
structural isomers Three major monosaccharides glucose, galactose and fructose mainly produced by digestion of complex carbohydrates

10 Sugar Derivatives The hydroxyl groups of a simple monosaccharide can be replaced by other groups

11 Alpha (a) and Beta (b) Links
The hydroxyl group on the carbon that carries the aldehyde or ketone can rapidly change from one position to the other b a

12 Disaccharides Pairs of monosaccharides Three major disaccharides
sucrose glucose + fructose lactose glucose + galactose maltose glucose + glucose

13 Dehydration Synthesis of a Disaccharide
Dehydration synthesis of two glucose molecules results in the formation of maltose The C-O-C bond formed is called a glycosidic bond

14 Polysaccharides Starch, cellulose and glycogen
long chains of glucose form these polysaccharides Starch produced by plants is digested by amylase Cellulose gives structure to plants, fiber to our diet

15 Starch Hydrolysis The digestion of starch occurs by the hydrolysis of the glycosidic bond. Amylase is the enzyme. Maltose is the product.

16 Polysaccharides Glycogen is an energy storage polysaccharide produced by animals Liver cells synthesize glycogen after a meal to maintain blood glucose levels

17 Carbohydrate Functions
Source of energy Conjugated carbohydrates glycolipids external surface of cell membrane glycoproteins mucus of respiratory and digestive tracts proteoglycans carbohydrate component dominant cell adhesion, gelatinous filler of tissues (eye) and lubricates joints

18 Moieties of Macromolecules
A moiety is a chemically different component of a conjugated macromolecule Glycolipid glycoprotein

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