Energy storage, polysaccharides

If a-glucose is polymerized, the result is either starch or glycogen. Starch is the polysaccharide energy storage molecule used by plants, and is found in potatoes, rice, maize, corn and cassava, among many others. It is the most common carbohydrate in the human diet. 

It has been estimated that >90% of the carbohydrate mass in nature is in the form of polysaccharides. In living organisms, carbohydrates play important roles. In terms of mass, the greatest amounts by far are stmctural components and food reserve materials, in that order and both in plants. However, carbohydrate molecules also serve as stmctural and energy storage substances in animals and serve a variety of other essential roles in both plants and animals. 

Starch is the major energy storage polysaccharide of cereal crops. It is a natural polymer of dextrose. Starch has two naturally occurring... 

Polysaccharide A biopolymer composed of two or more simple sugars, such as glucose. They are used for energy storage in organisms. 

For energy storage, sugars are metabolized to polysaccharides such as glycogen and starch and are stored as such. 

While starch is the major structural polysaccharide, plant energy storage and regulation utilize a combination of similar polysaccharides that are referred to as starch. Starch can be divided into two general structures, largely linear amylose (structure 9.17) and largely branched amylopectin (structure 9.18). 

Starch and Glycogen Are Major Energy-Storage Polysaccharides... 

Glycolysis entails the breakdown of hexoses to 3 carbon compounds while producing ATP. The reverse process, gluconeogenesis entails the synthesis of hexose and related energy storage polysaccharides in a process that consumes ATP. 

It is a remarkable fact that the main energy-storage polysaccharides and the main structural polysaccharides found in nature both have a primary structure of (l,4)-linked polyglucose. Why should two such closely related compounds be used in totally different roles A closer look at the stereochemistry of the a and /3 glycosidic linkage for polyglucose indicates why this is so. 

Glycolysis involves the breakdown of energy-storage polysaccharides or glucose to the 3-carbon acid, pyruvate. Its function is to produce energy in the form of ATP and 3-carbon intermediates for further metabolism. Glycolysis occurs under both aerobic and anaerobic conditions. 

The polysaccharide inulin is an energy-storage substance found in the tubers of a number of plants. 

Dextran is a naturally occurring polymer that is synthesized in yeasts and bacteria for energy storage. It is mainly a linear polysaccharide consisting of repeating units of... 

Polysaccharide glycogen (animals) and starch (plants) produced for energy storage from glucose... 

Polysaccharides function mainly either as structural components or as forms of energy storage. 

Starch is the major energy storage polysaccharide of cereal crops. It is a natural polymer of dextrose. Starch has two naturally-occurring forms one is amylose, a polymer with long linear chains the other is amylo-pectin which is a branched chain polymer. The length of the amylose chain varies between different plants but common values are between 200... 

Glycogen is similar in structure to amylopectin, but branches more frequently (Figure 1.3). Starch and glycogen polysaccharides provide structures that are used for energy storage, in plants and animals respectively. 

Energy Storage Polysaccharides Amylose, Amylopectin and Glycogen... 

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