CHAPTER: BIOLOGICAL MACROMOLECULES

• 4 Classes of Biological Macromolecules:

  • Carbohydrates - provide energy to the body; mainly composed of starch
  • Lipids - compounds that are nonpolar (hydrophobic) in nature
  • Proteins - one of the most abundant organic molecules in living systems
  • Nucleic Acids - the most important macromolecule for the continuity of life
• Monomers - single subunits or building blocks
• Polymers - monomers combine to form larger molecules
• Biological Macromolecule - large molecules, necessary for life
• Dehydration Synthesis - "to put together while losing water"
• Dehydration Synthesis - where monomers release water as byproducts
• Hydrolysis - "to split water"
• Hydrolysis - a water molecule is used during a breakdown
• Dehydration and hydrolysis reactions are catalyzed, or "sped up," by specific enzymes
• Dehydration reactions - involve the formation of new bonds, requiring energy
• Hydrolysis reactions - break bonds and release energy
• Carbohydrates are broken down by: Amylase, Lactase, Sucrase, Maltase
• Lipids are broken down by: Lipase
• Proteins are broken down by: Pepsin, Peptidase
• 3 Subtypes of Carbohydrates:

  • Monosaccharide (mono=one) - most common is glucose; carbons = 3 to 7
  • Disaccharide (di=two) - two monosaccharides undergo a dehydration reaction
  • Polysaccharide (poly=many) - long chain of monosaccharides
• Aldose - if the sugar has an aldehyde group (R-CHO)
• Ketose - if the sugar has a ketone group (RC(=O)R')
• Carbohydrates - represented by the stoichiometric formula (CH2O)n, where n is the number of carbons in the molecule
• Carbohydrates - are made up of carbon, hydrogen and oxygen, with a 1:2:1 ratio
• Hydrogen Atom = H+ ; Hydroxyl Molecule = OH-
• Glucose - an important source of energy; C6H12O6 ratio
• Galactose - part of lactose (milk sugar)
• Fructose - found in sucrose, in fruit; (table sugar)
• Triose - 3 carbons

  Pentose - 5 carbons

  Hexose - 6 carbons
• When energy is released from glucose, the energy used helps to make Adenosine Triphosphate (ATP).
• Glycosidic Bond - a covalent bond between a carbohydrate molecule and another molecule
• Examples of Disaccharides:

  1. Lactose - milk sugar; Glucose + Galactose
  2. Maltose - malt sugar; Glucose + Glucose
  3. Sucrose - table sugar; Glucose + Fructose
• Examples of polysaccharides:

  • Starch - form of sugar in plants; amylose + amylopectin
  • Glycogen - form of glucose in humans
  • Cellulose - cell wall; wood and paper
  • Chitin - a major component in fungal cell walls
• Cellulase - a enzyme that can break down cellulose into glucose monomers
• Glycogenolysis - glycogen is broken down to release glucose whenever blood glucose levels decrease
• Fiber - insoluble part in plants; mostly cellulose; promotes regular bowel movement by adding "bulk"
• To lose weight, a low-carb diet is recommended.
• Examples of Lipids:

  • Fats - glycerol + fatty acid
  • Oils - liquid at room temperature
  • Waxes - hydrophobic nature; feathers of animals
  • Phospholipids - major components of the plasma membrane
  • Steroids - fused ring structure; grouped with lipids as they are hydrophobic
• Glycerol - organic compound with 3 carbons, 5 hydrogens, and 3 hydroxyl groups
• Fatty acids - long chain of hydrocarbons
• Fats - "triacylglycerols" or "triglycerides" because of its chemical structure
• Palmitic Acid, a saturated fatty acid, comes from Palm Trees.
• Arachidic Acid = "Arachis hypogea" (groundnuts or peanuts)
• Unsaturated Fatty Acid - when the hydrocarbon chain contains a double bond; example is Oleic Acid
• Adipocytes - where mammals store fats