Carbohydrates and Lipids

• Carbon can form up to 4 covalent bonds, allowing for the formation of diverse compounds
• Carbon atoms can form long chains with different lengths, arrangements (straight, branched, ring), and bond types (single, double, triple)
• Different bonds, rings, and functional groups can be added to the carbon skeleton to change the properties of the molecule
• Carbohydrates and lipids are both used as energy storage compounds
• Carbohydrates:

  • Monosaccharides like pentoses and hexoses are used for energy
  • Polysaccharides like starch in plants and glycogen in animals are compact and insoluble for energy storage
  • Cellulose, a structural polysaccharide in plants, has straight chains with hydrogen bonds
• Lipids:

  • Include fats, oils, waxes, and steroids
  • Triglycerides and phospholipids are formed by condensation reactions
  • Saturated, monounsaturated, and polyunsaturated fatty acids differ in double carbon bonds affecting melting point
  • Triglycerides in adipose tissues are used for long-term energy storage and thermal insulation
• Phospholipid bilayers are formed due to the hydrophobic and hydrophilic regions of phospholipids
• Non-polar steroids like oestradiol and testosterone can pass through the phospholipid bilayer
• Metabolism involves dehydration synthesis to form polymers and hydrolysis to break them down
• Dehydration synthesis:

  • Monomers form larger molecules by removing water molecules
• Hydrolysis:

  • Polymers disassemble by adding water molecules
• Condensation reactions consume energy, form covalent bonds, and remove water to link monomers into polymers
• Hydrolysis reactions release energy, break covalent bonds, and add water to break down polymers into monomers
• Macromolecules are large molecules (polymers) composed of smaller molecules (monomers)
• Carbohydrates are composed of monosaccharides, which are simple sugar molecules containing C, H, O (CH2O)n
• Monosaccharides are short-term energy storage molecules and their names often end in -ose
• Glucose is a hexose (6-sided) sugar that fuels respiration and forms the base unit for many polymers
• Galactose is a hexose sugar found in milk and cereals, less sweet than glucose
• Fructose is a pentose sugar commonly found in fruits and honey, the sweetest naturally occurring carbohydrate
• Ribose is a pentose sugar that forms the backbone of RNA
• Monosaccharide monomers are joined by condensation reactions to form polymers, with water as a waste product
• Disaccharides are formed by the bonding of two monosaccharides, such as maltose (glucose + glucose), lactose (glucose + galactose), and sucrose (glucose + fructose)
• Polysaccharides are polymers of sugars and serve various roles in organisms
• Starch is a plant polysaccharide made of α-glucose molecules, the major storage form of glucose in plants
• Glycogen consists of glucose monomers and is the major storage form of glucose in animals, stored in the liver and muscles
• Cellulose is a polymer of glucose and a major component of plant cell walls
• Glycoproteins are sugar-protein molecules that perform vital biochemical and structural functions
• ABO blood grouping is based on differences in the type of glycoprotein present on red blood cells
• Cell-cell recognition and cell adhesion are roles of glycoproteins
• Glucose, sucrose, and fructose are different types of sugars
• Glucose is a monosaccharide
• Sucrose is a disaccharide composed of glucose and fructose
• Fructose is also a monosaccharide