Summary of Section 5.2 ;;)

-=Sugars=-

~*~Carbohydrates~*~

Definiton: a compound containing carbon (organic compound) that is made out of sugar molecules 

Carbohydrates provide a good source of energy ;)

Formula : CH2O ( 1 carb0n : 2 hydrogen : 1 oxygen) 

~*~Monosaccharides~*~

Definition: Simple sugars that contains 1 sugar unit 

Examples: Glucose, Fructose, Galactose 

Sugars molecules are used for: 

 

1. for cellular work :

- Cells break down sugar molecules and take their stored energy

2. use carbon skeletons of monosaccharides for making other types of organic molecules 

3. Glucose molecules that are not used immediatly cam be incorporated into larger carbohydrates or can be stored for later use. 

~*~Disaccharides~*~

Definition: when there is a dehydration reaction, cells construct a disaccharide from two monosaccharides

most common disaccharide: sucrose

sucrose : fructose + glucose

once consumed, sucrose can be broken down into:

-glucose 

-fructose

can also store glucose in large molecules for later use.

~*~Polysaccharides~*~

Definition: polymer chains made up of simple sugar monomers (can also be called complex carbohydrates)

Examples: 

**starch: found in plant cells that consists of only sugar monomers

-starch chains serve as sugar stockpiles

-plant and animal cells need sugar for energy to perform work + use as raw material for building other molecules

-when plants break down starch molecules: the stored glucose becomes available

starch can be found in:

-potatoes

-rice

-corn

-wheat

**glycogen: 

Definition: polysaccharide in animal cells 

-like starch, consists of glucose monomers 

BUT: 

a glycogen polymer is more highly branched than a starch polymer

-in humans, most glycogen is stored in muscle and liver cells

-when body needs energy, it breaks the glycogen and releases the glucose

**cellulose: 

Definition: a polysaccharide in a plant

-serves as building material

-protect and stiffen plant

-like starch + glycogen is made out of glucose monomers

-many cellulose chains are linked together with:

hydrogen bonds that make fibers in the tough walls of the plant cells 

-cellulose helps keep your digestion healthy 

-is not a nutrient

-almost all carbohydrates are hydrophillic because:

there are many hydroxyl groups in their sugar units so...

monosaccharides + disaccharides dissolve in water = sugary solutions

starch + cellulose are large molecules so they DO NOT dissolve in water

BUT

they are still hydrophillic (water-loving) 

that's all for now

Concept Check:

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

A monosaccharide ia a simple sugar that contains one sugar unit while disaccharides are made when there is a dehydration reaction. a disaccharide is composed of 2 monosaccharides.

Example of a monosaccharide: glucose, fructose 

Example of disaccharide: sucrose 

2.Compare and contrast starch, glycogen and cellulose. 

-Starch, glycogen and cellulose are all polysaccharides

-all three of them are made out of glucose monomers

-A glycogen molecule is more highly branched than a starch molecule

-starch and glycogen can be digested by people and animals 

-starch and cellulose are both in plants

-cellulose and some forms of starch do not dissolve in water

3.How do animals store excess glucose molecules?

Animals store excess glucose molecules in glycogen.