Summary of 5.2

CONCEPT 5.2: Carbohydrates provide fuel and building materials.

Key Terms:

carbohydrate -- organic compound made up of sugar molecules

monosaccharide -- simple sugars contain just one sugar unit

disaccharide -- sugar with two monosaccharides

polysaccharide -- complex carbohydrates

starch -- polysaccharide found in plant cells that consists entirely of gluecose monomers

glycogen -- store excess sugar in the form of a polysaccharide

cellulose -- polysaccharide consisting of gluecose monomers that reinforces plant-cell walls

Notes:

Sugars

* carbohydrate - made up of sugar molecules

* sugars contain carbon, hydrogen, annd oxygen

-formula: CH2O

-most found in nature: carbon skeletons (have a ring shape)

Monosaccharides

* monosaccharides

-ex. glucose, fructose, and galactose

--honey contains both glucose and fructose

* glucose

-straight-chain form

-ring-shaped form

* sugar molecules (particularly glucose)are the main fuel supply for cellular work

*cells use carbon skeletons of monosaccharides as raw material for manufacturing other kinds of organic molecules

Disaccharides

* disaccharide -- "double sugar" from two monosaccharides

-the most common one is sucrose

--sucrose is a major carbohydrate in plant sap, and it nourishes all the parts of the plant

---ex.maple trees (maple syrup)

* body can store glucose in larger molecules for later use

Polysaccharides

* polysaccharides - complex carbon hydrates

-ex. starch - found in plant cells that consists entirely of glucose monomers

--ex. for starch: potatoes, rice, and corn

* plant and animal cells need sugar for energy to work

* glycon is a chain of many glucose monomers

* cellulose protect cells and stiffen the plant, preventing it from flopping over

Concept Check 5.2

1. Explain the difference between a monosaccharide and a disaccharide. Give an example of each.

Monosaccharides are simple sugars contain just one sugar unit, and the examples for this are glucose, fructose, and galactose; however, disaccharide is formed by two sugar or monosaccharides, and the examples for this is the maple tree.

2. Compare and contrast starch, glycogen, and cellulose.
Starch, glycogen, and cellulose are all found in polysaccharide. Starch is foundin plant cells that consists entirely of glucose monomers. Glycogen is a chain of many glucose monomers (in turkeys and humans). Cellulose protect cells and stiffen the plant, preventing it from flopping over.

3. How do animals store excess glucose molecules?