Скачать или смотреть 2.6C Carbohydrates used for energy and structural support

What is a polysaccharide?
What is glycogen?
What is starch?
What is cellulose?
In this video, we discuss two polysaccharides that are used to store energy and one polysaccharide that is used for structural support.
• Polysaccharides (complex carbohydrates) store energy
o A polysaccharide consists of many monosaccharides covalently bonded to one another
 The prefix poly means many
 saccharide means carbohydrate unit (CnH2nOn)
o In animals, glucose monomers are joined together to form a polymer called glycogen.
• In plants, glucose monomers are joined together in a slightly different manner to form a polymer called starch.
o Starch is the main energy storage carbohydrate in plants.
• Carbohydrates provide structural support in plants
o Unlike glycogen and starch, cellulose is insoluble in water (it does not dissolve in water).
o Cellulose is the main constituent of plant cell walls and of vegetable fibers such as cotton.
o Fruits and vegetables are rich sources of cellulose.
o Cellulose cannot be digested by humans.
o Cellulose in food is one type of dietary fiber.
o Cellulose encourages movement of food through the intestines, thus helping to prevent constipation and irregularity.
o Cellulose lowers the risk of colon cancer.
o Fiber-rich foods help a person to maintain a healthy body weight.