Carbohydrates

• Carbohydrate

  • most abundant class of bioorgnanic mols
• Sources of carbohydrates:

  • green plants - capable of synthesizing glucose from CO2 & water, using solar energy : photosynthesis

  
• 2 main uses for carbohydrates in plants:

  1. Cellulose (carbohydrates) - structural elements
  2. Starch - energy reserves
• Functions of Carbs in humans:

  1. Carbs oxidation provides energy
  2. Carbs storage in the form of glycogen: a short-term energy reserve
  3. Carbs supply carbon atoms for synthesis of biochemical substances (proteins, lipids, nucleic acids)
  4. Carbs form part of the structural framework of DNA & RNA mols
  5. Carbs linked to proteins function in a variety of recognition process
  6. Carbs linked to lipids are structural components of cell membrane
• Carbohydrates Empirical Formula:

  CnH2nOn
• Carbohydrates is a polyhydroxy aldehyde, a polyhydroxy ketone or a compound that leads to either upon hydrolysis.
• Glucose - polyhydroxy aldehyde

  Fructose - polyhydroxy ketone
• Aldose - carbohydrate w/ aldehyde group

  Ketose - carbohydrate w/ ketone group
• Monosaccharide

  • contains a single polyhydroxy aldehyde/ketone
  • water-soluble
  • white crystalline solids

  
• NUmber of C atoms

  A) trioses

  B) tetroses

  C) pentoses

  D) hexoses

  E) heptoses

  F) nonoses

  G) glyceraldehyde

  H) erythrose

  I) ribose

  J) Glucose, fructose

  K) seduheptulose

  L) neuraminic acid

  
• Common Monosaccharide

  A) primary energy source

  B) fruits, veggies, honey

  C) sweeter than glucose, energy source

  D) fruits, honey, root veggies

  E) important for glycoproteins/lipids

  F) dairy products

  G) part of RNA & ATP

  H) synthesized

  I) part of DNA

  J) synthesized

  K) glycosylation

  L) fruits, veggies, glycoproteins

  
• Oligosaccharide

  • contains 2-6 monosaccharide units
  • water-soluble
  • crystalline
  • joined by condensation reaction
• Polysaccharide

  • contains many (7+) monosaccharide units
  • formed by condensation reaction
• types of CHO (carbohydrates) are related to each other through hydrolysis

  
• Polysaccharides/Glycans

  
• Starch

  • CHO reserved in plants
  • 2 types of glucose polymer
  • Ex. Cereals, roots, tubers veggies
• Dextran

  • breakdown product of starch
  • Ex. several commercial products
• Inulin

  • polymer of fructose
  • water-soluble
  • for assessing kidney function
  • Ex. dahlia bulbs, garlic, onion
• Glycogen

  • main storage polysaccharide in animal cell
  • abundant in liver
• Cellulose

  • cannot be digested by mammals (due to lack of enzymes)
  • can be contained by certain ruminants & herbivores
  • microorganisms in the gut
  • most abundant polysaccharide, major constituent of fiber
• Chitin

  • structural polysaccharide found in the exoskeleton
  • 2nd most abundant polysacc.