Bio-molecules

• Carbohydrates are the most abundant biomolecules on Earth, found everywhere, and a major source of energy for all living organisms such as animals and plants
• Carbohydrates are not only important for energy, they also serve as important structural components, e.g. DNA contains the carbohydrate ribose and plant cell walls are made of the carbohydrate cellulose
• Carbohydrates


  Molecules containing carbon, hydrogen, and oxygen atoms in a molar ratio of 1:2:1
• Types of carbohydrates


  • Monosaccharides
  • Disaccharides
  • Oligosaccharides
  • Polysaccharides
• Monosaccharides


  The smallest units that make up carbohydrates, also called simple sugars
• Main monosaccharides in the human diet

  • Glucose
  • Galactose
  • Fructose
• Glucose


  • Contains 6 carbon atoms
  • Can be in alpha or beta configuration
• Disaccharides


  Made up of two monosaccharides linked together
• Disaccharides

  • Maltose
  • Lactose
  • Sucrose
• Forming disaccharides


  1. Condensation reaction (removal of water)
• Maltose


  • Two glucose molecules linked by an alpha 1-4 glycosidic bond
• Lactose


  • Galactose and glucose linked by a beta 1-4 glycosidic bond
• Sucrose


  • Glucose and fructose linked by a glucose alpha 1 - fructose beta 2 bond
• Oligosaccharides


  Short chains of monosaccharides, typically less than 20
• Polysaccharides


  Long chains of monosaccharides, more than 20
• Homo-polysaccharides


  • Can be unbranched or branched
• Starch


  • Made of glucose, can be unbranched (amylose) or branched (amylopectin)
  • Branch points have alpha 1-6 glycosidic bonds
• Glycogen


  • Made of glucose, similar to starch but more frequently branched
• Cellulose


  • Unbranched homo-polysaccharide of glucose in beta configuration, linked by beta 1-4 glycosidic bonds
  • Humans cannot digest cellulose
• Starch (storage of energy in plants):

  made entirely out of glucose:

  amylose : unbranched (a1-4 glycosidic bonds)

  amylopecitin : branched (a1-4 and a1-6 glycosidic bonds)

  branch point every 28-30 glucose atoms
• mono and disaccharides are readily soluble in water,while polysacchrides are not.
• Most of the molecules in living organisms fall into three categories: carbohydrates, proteins and lipids
• These all contain carbon and so are described as organic molecules
• Carbohydrates


  Long chains of simple sugars
• Glucose


  A simple sugar (a monosaccharide)
• Maltose

  When 2 glucose molecules join together (a disaccharide)

  
• Starch, glycogen or cellulose

  When lots of glucose molecules join together (a polysaccharide)

  
• Glycogen, cellulose and starch are all made from glucose molecules

  
• Carbohydrates

  • Monosaccharides – sugars with a single carbon ring, eg. glucose, fructose
  • Disaccharide – sugars with two carbon rings, eg. maltose, sucrose
  • Polysaccharide – many glucose molecules joined together, eg. glycogen (found in animals), starch (found in plants)
  • Cellulose – consists of even longer chains of glucose molecules

  
• Mono- and disaccharides are readily soluble in water
• Polysaccharides are not readily soluble in water
• Carbohydrates play an important role in the human body. They act as an energy source, help control blood glucose and insulin metabolism, participate in cholesterol and triglyceride metabolism, and help with fermentation
• All the monosaccharides have the formula as (CH2O) n. Here, the two hydrogen atoms and one oxygen atom associate itself to the central carbon molecule. A hydroxyl group is formed when oxygen will bond with hydrogen. Several carbon molecules bond together because 4 bonds can form on carbon
• Starch, cellulose and glycogen are all polysaccharides made up of glucose subunits. Both starches and cellulose are made of glucose molecules, but the difference between them is that starch is a branched polymer, while cellulose is a linear polymer. This difference makes starch more digestible than cellulose

  
• Carbohydrates are biological molecules made of carbon, hydrogen, and oxygen in a ratio of roughly one carbon atom to one water molecule. This composition gives carbohydrates their name: they are made up of carbon (carbo-) plus water (-hydrate)

  
• Dietary fiber increases the weight and size of your stool and softens it. A bulky stool is easier to pass, decreasing your chance of constipation. If you have loose, watery stools, fiber may help to solidify the stool because it absorbs water and adds bulk to stool. Helps maintain bowel health
• Carboxyl group


  
  
• A functional group consisting of a carbon atom double-bonded to an oxygen atom and single-bonded to a hydroxyl group (-OH). Found in carboxylic acids.
• Hydroxyl group


  
  
• A functional group consisting of a hydrogen atom bonded to a hydroxide ion. Found in many biological molecules, including carbohydrates, proteins, and lipids.