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Lipids and Carbohydrates

Page history last edited by Zachary Tullis 14 years, 7 months ago

Carbohydrates

 

Carbohydrates are classified into three groups according to the number of sugar molecules that are there.

 

 

Monosaccharide- is the simplest kind of a carbohydrate. It is made up of a single sugar molecule that is either fructose or glucose.

 

 

 

 

 

 

 

 

 

 

 

 

Disaccharide- this carbohydrate consists of two sugar molecules joined by a glycosidic linkage. So when glucose or fructose lint to make up sucrose, the formula is C12H22O11.

 

 

Examples of common disaccharide:

 

  1. glucose + fructose = (common table sugar)
  2. glucose + galactose= (the sugar in milk)
  3. glucose + glucose= (maltose)

 

 

Polysaccharide is made up of a series of connected monosaccharides. Thus, a polysaccharide is a polymer because it consist repeating units of a monosaccharide.

 

Examples of Polysaccharides:

 

  1. Starch is a polymer of (a)-glucose molecules. It is the principle energy storage in plant cells.
  2. Glycogen is a polymer of (a)-glucose molecules. It differs from starch by its pattern of polymer branching. It is a major energy storage molecule in animal cells.
  3. Cellulose is a polymer of (b)-glucose molecules. It serves as a structural molecule in the walls of plant cells and is the major component of wood.
  4. Chitin is polymer similar to cellulose, but each (b) glucose molecule has a nitrogen-containing group linked to the ring. Chitin serves as a structural molecule in the walls of fungus cells and in the exoskeletons of insects, other arthropods, and mollusks.

 

Lipids

 

 

 

Lipids are broadly defined as any fat-soluble , naturally-occurring molecule, such as fats, oils, waxes, cholesterol, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, triglycerides, phospholipids, and others. The main biological functions of lipids include energy storage, as structural components of cell membranes, and as important signaling molecules.

 

 

  1. Triglycerides include fats and oils. They consist of three fatty acids attached to the glycerol molecule.
  • A saturated fatty acid has a single covalent bond between each pair of carbon atoms, and each carbon atoms have two hydrogen bonded to it.
  • A monounsaturated fatty acid had one double covalent bond and ach of the two carbons in this bond has one hydrogen atom bonded to it.
  • A polyunsaturated fatty acid is similar to a monounsaturated fatty acid except that there are two or more double covalent bonds.

 

  1. Phospholipids are a class of lipids and are a major component of all cell membranes. It looks just like a lipid except that one of the fatty acids is replaced by a phosphate group. Phospholipids are determined by an amphipathic molecule because it has both polar and non polar regions. They are usually found in sandwich like formations with the hydrophobic tails grouped together on the inside and the hydrophilic heads facing the inside.
  2. Steroids are classified by the backbone of four linked carbon rings.

Examples of Steroids

 

  • Cholesterol
  • Certain hormones, including testosterone and estrogen.

 

 

 

 

 

Page Created by: Vivian, Zeljana, Julie

 

Comments (1)

wikiuser0019 said

at 1:52 pm on Jun 3, 2009

okay

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