Chapter 5.2 Summary

Carbohydrates provide fuel and building material.

Sugars
carbohydrate

: an organic compound made up of sugar molecules

- The sugar formula = 1 carbon: 2 hydrogen: 1 oxygen

- the core of a sugar molecule is a ring-shaped carbon skeleton

Monosaccharides(simple sugars)

: sugars that contain only one sugar unit
ex. Glucose, fructose and galactose

- Sugar molecules act as fuel for cellular work (Cells breakdown sugar and extract stored energy

Disaccharides

: are two sugars linked together

- formed using dehydration reaction
ex. sucrose, a glucose linked with a fructose (major carbohydrate found in plant sap)

 
Polysaccharides

polysaccharides(complex sugar)

: are long polymer chains made up of simple sugar monomers
starch

: polysaccharides found in plant cells, and it consists entirely of glucose monomers
Glycogen

: a form of polysaccharide that animal cells store and is a chain of many glucose monomers like starch
- When in need of energy, the body would breakdown glycogen and turn it into glucose
Cellulose

: a polysaccharide found in plants, is made of glucose monomers
- building materials and strengthening plants
- Humans and most animals cannot digest cellulose (fiber)
- Almost all carbohydrates are hydrophilic due to the hydroxyl groups in their sugar units
- Monosaccharides and disaccharides can dissolve in water
- cellulose and some types of starch cannot because they have such large molecules.

Concept Check

1. Explain the difference between a monosaccharide and a disaccharide.Give an example of each.
   The difference between a monosaccharide and a disaccharide is that a monosaccharide is made up of only one unit of sugar (ex. glucose). A disaccharide is made up of two monosaccharides (ex. sucrose).
2. Compare and contrast starch, glycogen, and cellulose.
   Starch, glycogen and cellulose are all polysaccharides and they all consists of glusoce monomers. Starch is found in plant cells while glycogen is found in animals, but they both store energy in cells. Cellulose is strengthens the plant, also it is found in both animals and plants, but most animals cannot digest it.
3. How do animals store excess glucose molecules.
   Animals store excess glucose molecules in the form of glycogen. When the body needs energy, it would breakdown glycogen granules to release the stored glucose molecules.