Chapter Five Concept 5.2

INFORMATION FROM:
Pearson Prentice Hall, BIOLOGY Exploring Life textbook.

SUGAR: (contains elements carbon, hydrogen and oxygen) 1. carbohydrate:
"I'm on an all-carb diet." I was always wondering what that really meant. Well firstly because I couldn't imagine life eating only carb-foods (which is ironic, because I didn't even know what carbs were), and secondly because I lacked the knowledge of how carbs can help your body.
Definition for carbohydrate-
carbohydrate: an organic compound made up of sugar molecules.
formula: CH20
Carbohydrates is an source of energy that lasts for a long period of time, and is stored for a long time.
ex) in starch, spaghetti, bread, rice, potatoes, sports drinks.
-most of these examples are crucial to the bottom of the food pyramid, and is needed for the body to function.


2. monosaccharides:
Definition-
monosaccharides: simple sugars which contain just one sugar unit.
ex.) glucose, fructose, and galactose. (mostly with suffixes -ose meaning full or full-of.
-honey, and sweets include monosaccharides.
-main fuel supply for cellular work.
-cells use the carbon skeletons of monosaccharides as raw material for making other organic molecules.


3. disaccharides:
Definition-
disaccharides: sugar with two monosaccharides. a "double sugar"
ex.) sucrose
Sucrose*
-consisting of glucose molecule linked to a fructose molecule.
-major carbohydrate in plant sap.
-when consumed, can be broken down to glucose and fructose.
-body can store glucose in larger molecules for later use.


4. polysaccharides:
Definition-
polysaccharides: long polymer chain made up of simple sugar monomers. complex carbohydrates.
ex.) starch, glycogen, cellulose,etc.
starch: polysaccharid found in plant cells that consists entirely of glucose monomers.
-starch chains that are jumbled up is called a sugar stockpile.
-energy is used as a raw material for work, when a plant breaks down starch molecules, glucose becomes available.
-Humans also use starch as food for breaking it down in their digestive systems.
ex. of starch) corn, potato, pasta, rice.


glycogen: polysaccharide in animal cells that consist of many glucose monomers.
-has a highly branched system than starch polymers.
-in humans, it is stored in granules in lover and muscle cells.
-when body needs energy, it breaks down the glycogen granules and releases glucose.


cellulose: polysaccharide consisting glucose monomers that reinforces plant-cell walls.
-protects and stiffens the plant, prevents from falling over.
-multiple cellulose chains are linked together with hydrogen bonds.
-most humans and animals cannot digest cellulose (lack molecule necessary to break bonds between the glucose monomers in cellulose.


interesting facts:
-most of carbohydrates are hydrophilic for many hydroxyl groups in their sugar unites.
-cellulose and some forms of starch have large molecules that do not dissolve in water.
(why cotton towels can absorb so much water)

Concept Check 5.2:

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 monosaccharides only have one sugar unit whereas a disaccharide has two sugar units. An example of a monosaccharide would be sweet things such as glucose and fructose (notice how the suffix is -ose because it is sugar) An example of a polysaccharide would be glycogen, starch and cellulose

2. Compare and contrast starch, glycogen and cellulose.

A similarity between all these polysaccharides are made up of chains of many glucose monomers. Starch is found in plant cells like a potato and chains up into numerous branches whereas glycogen is not found in plants, but animals. Glycogen is more highly branched than starch polymers and is stored in humans and animals. (for humans, in the liver and muscle cells). Cellulose is also found in plants like starch except cellulose is used for protecting plants and stiffening it. 

3. How do animals store excess glucose molecules?

Animals store excess glucose molecules in glycogen because it is more highly branched than other polysaccharides and because they store excess sugars.