Carbohydrates

• What are carbohydrates considered in nature?

  The most abundant organic molecules
• What are the various functions of carbohydrates?

  • Dietary requirement
  • Storage form of energy
  • Component of cell membrane
  • Structural components of many organisms
• How are carbohydrates classified based on the number of sugars?

  • Monosaccharides: 1 saccharide
  • Disaccharides: 2 monosaccharides
  • Oligosaccharides: 3-10 monosaccharides
  • Polysaccharides: >10 monosaccharides
• What is an example of a monosaccharide?

  Glucose
• What is an example of a disaccharide?

  Sucrose
• How are monosaccharides classified based on the number of carbon atoms?

  Trioses, Tetroses, Pentoses, Hexoses
• What distinguishes aldoses from ketoses in monosaccharides?

  Aldoses have carbonyl at the end; ketoses elsewhere
• What are isomers?

  Compounds with the same formula but different structures
• What happens during the cyclization of monosaccharides?

  • Monosaccharides can form ring structures
  • Less than 1% exists in open-chain form
  • Creates an anomeric carbon (former carbonyl carbon)
• What is the significance of glycosidic bonds in carbohydrates?

  • Link monosaccharides to form di-, oligo-, or polysaccharides
  • Catalyzed by glycosyltransferases
• What are examples of important polysaccharides?

  Glycogen, starch, cellulose
• What is the main storage form of glucose in plants?

  Starch
• What is the structure of amylose in starch?

  α helix structure

  
• What is the role of glucose in the human body?

  Important energy source in all cells
• What is the main sugar in the human body?

  Glucose
• Why can't glucose be stored in its form?

  It affects osmotic balance
• What is ribose used for in the body?

  In nucleotides and nucleic acids
• What are glycoproteins and glycolipids made from?

  Glucose and other carbohydrates
• What is the role of glucose in the plasma membrane?

  Present in plasma membrane
• What is the process of dehydration reaction in glycosidic bond formation?

  • Monosaccharides join to form disaccharides
  • Water is released during the reaction
• What is the glycosidic bond in sucrose?

  α(1→2) glycosidic bond

  
• What are common disaccharides and their components?

  • Lactose: β-galactose + α-glucose
  • Maltose: α-glucose + α-glucose
  • Sucrose: α-glucose + β-fructose
• What defines a reducing sugar?

  Can open its ring and act as a reducing agent
• Why are all monosaccharides considered reducing agents?

  They can open their ring structure
• What happens to the aldehyde group in reducing sugars?

  It undergoes oxidation to form carboxylic acid
• What is the significance of the aldehyde group in reducing sugars?

  It allows sugars to undergo oxidation readily
• What is the main test for detecting reducing sugars?

  Benedict’s Test
• What is the result of Benedict’s Test with glucose?

  Changes from blue to red
• What is the main storage form of glucose in animals?

  Glycogen
• What is the role of glycogen in the body?

  Storage form of glucose in animals
• What is the structure of cellulose?

  Polymers of glucose
• What is the primary function of starch in plants?

  Main storage form of glucose
• What percentage of starch is accounted for by amylose?

  ~20%
• What is the structure of amylose?

  α helix structure

  
• What are the key characteristics of carbohydrates?

  • Composed of carbon, hydrogen, and oxygen
  • Serve as energy sources and structural components
  • Classified by the number of sugar units
• What are the types of glycosidic bonds?

  • α-bond: anomeric hydroxyl in α configuration
  • β-bond: anomeric hydroxyl in β configuration

  
• What are the differences between reducing and non-reducing sugars?

  • Reducing sugars can open their ring structure
  • Non-reducing sugars cannot open their ring structure
• What are the roles of glucose in the body?

  • Energy source for cells
  • Building block for polysaccharides
  • Component of nucleotides
• What type of sugars can react with chromogenic agents?

  Reducing sugars
• What happens to the aldehyde group in reducing sugars?

  It becomes oxidized