Carbohydrates & Lipids

• What are the two essential biological molecules discussed in the overview?

  Carbohydrates and lipids
• What roles do carbohydrates and lipids play in biological systems?

  • Energy storage
  • Structural integrity
  • Cellular functions
• What are monosaccharides?

  The simplest form of carbohydrates
• How do monosaccharides link together?

  Through condensation reactions
• What is a condensation reaction?

  When two molecules join, releasing a water molecule
• What are disaccharides and how are they formed?

  • Formed when two monosaccharides combine
  • Examples include sucrose, lactose, and maltose
• What is sucrose composed of?

  Glucose and fructose
• What is lactose composed of?

  Glucose and galactose
• What is maltose composed of?

  Glucose and glucose
• What happens during the formation of sucrose?

  The hydroxyl group of glucose reacts with that of fructose, releasing water
• What type of bond is formed in sucrose?

  A glycosidic bond
• What are polysaccharides and their roles in biological systems?

  • Formed when many monosaccharides link together
  • Roles include:
  • Cellulose: Structural polysaccharide in plant cell walls
  • Starch: Energy storage in plants
  • Glycogen: Energy storage in animals
• What is cellulose?

  A structural polysaccharide in plant cell walls
• What is starch used for in plants?

  Energy storage
• What is glycogen?

  The energy storage form in animals
• How is cellulose structured?

  It is a linear polymer of glucose units connected by β-1,4 glycosidic bonds
• What is the significance of the β-1,4 linkage in cellulose?

  It creates a flat structure allowing hydrogen bonding between chains
• What are the two types of glucose polymers in starch?

  Amylose and amylopectin
• How is amylose structured?

  As a linear chain linked by α-1,4 glycosidic bonds
• How is amylopectin structured?

  As a branched structure with α-1,4 and α-1,6 glycosidic bonds
• What is glycogen's structure compared to starch?

  Glycogen is more highly branched than starch
• Why is glycogen more highly branched?

  For faster energy mobilization
• What is the common mistake students make regarding glycogen?

  Confusing glycogen with glucose
• What are fatty acids?

  Building blocks of many lipids consisting of a carboxylic acid group attached to a hydrocarbon chain
• How are fatty acids classified?

  Based on double bonds
• What are saturated fatty acids?

  Fatty acids with no double bonds
• What are monounsaturated fatty acids?

  Fatty acids with one double bond
• What are polyunsaturated fatty acids?

  Fatty acids with multiple double bonds
• What is an example of a saturated fatty acid?

  Stearic acid (18:0)
• What is an example of a monounsaturated fatty acid?

  Oleic acid (18:1)
• What is an example of a polyunsaturated fatty acid?

  Linoleic acid (18:2)
• What are cis and trans isomers of fatty acids?

  • Cis Isomers: Hydrogen atoms on the same side of the double bond, causing a bend
  • Trans Isomers: Hydrogen atoms on opposite sides, resulting in a straighter shape
• What is the common form of stored fat?

  Triglycerides
• How are triglycerides formed?

  Through a condensation reaction between three fatty acids and one glycerol molecule
• What does the prefix "tri" in triglycerides refer to?

  Three fatty acids
• What does "glyceride" refer to in triglycerides?

  The glycerol backbone
• What are the health implications of trans fats and saturated fatty acids?

  • Linked to increased health risks, particularly cardiovascular diseases
  • Not all saturated fats are equally harmful; coconut oil may have different effects
• How should students evaluate health claims about lipids?

  • Assess research quality
  • Identify potential conflicts of interest
  • Distinguish correlation from causation
• What is the energy content of lipids compared to carbohydrates?

  Lipids provide 9 kcal/g, while carbohydrates provide 4 kcal/g
• Why are lipids more suitable for long-term energy storage?

  They are hydrophobic, allowing compact storage