Finals

• Lipids play various functions:

  • Energy storage
  • Structural components of cell membranes
  • Signaling molecules
  • Insulation
  • Protection of organs
• The difference between fats and phospholipids:

  • Fats: consist of three fatty acids linked to glycerol
  • Phospholipids: have two fatty acids and a phosphate group attached to glycerol
• Properties of water:

  1. Water has a high heat capacity due to hydrogen bonds allowing it to absorb heat without a significant change in temperature

  2. Water has a high heat of vaporization, requiring energy to change from liquid to gas

  3. Water is a solvent due to its polarity, facilitating chemical reactions inside and outside living organisms

  4. Water molecules are cohesive and adhesive, sticking to other polar molecules and each other due to hydrogen bonding

  5. Water has a high surface tension, caused by hydrogen bonding, with more hydrogen bonds leading to a stronger web

  6. Ice is less dense than liquid water, forming a regular crystal lattice when frozen due to molecules coming closer together
• Calorie: the amount of heat needed to raise the temperature of 1g of water by 1°C

  Solute: dissolved substances in a solution

  Hydrophilic: molecules that can attract water

  Hydrophobic: non-ionized and non-polar molecules that cannot attract water
• Sodium hydroxide and soap are examples of bases
• The pH scale is used to indicate the acidity or basicity (alkalinity) of solutions, ranging from 0-14
• A pH below 7 is acidic, a pH above 7 is basic, and a pH of 7 is neutral
• Acidosis occurs when blood pH drops below 7 Alkalosis happens when blood pH rises to about 7.8
• Organic molecules (aka molecules of life) contain carbon and hydrogen.

  The chemistry of carbon accounts for the formation of a variety of organic molecules; carbon atoms can share up to 4 electrons with other atoms.
• Monomers are simple organic molecules that can link with other monomers to form a polymer
• Examples of polymer-monomer pairs:

  • Carbohydrate: monosaccharide
  • Lipid: fatty acids
  • Protein: amino acids
  • Nucleic acid: nucleotide
• Hydrolysis reaction: the reaction of a compound to form 2 or more smaller molecules

  It works b/c components of water are added that degrades polymers.
• Carbohydrates are organic molecules characterized by the presence of the atomic grouping H-C-OH; the ratio of hydrogen atoms to oxygen atoms is 2:1
• Monosaccharides are simple sugars or carbohydrates with a low (3-7) number of carbon atoms
• Pentoses are 5-carbon sugars, hexoses are 6-carbon sugars; glucose is a hexose with the formula C6H12O6
• Glucose is an immediate source of energy for the body; fructose is found in fruits, and galactose in milk
• Disaccharides like maltose are made from 2 combined glucose molecules by removing a hydroxyl (OH) group and a hydrogen (H) from each glucose, in a dehydration reaction
• Polysaccharides are long polymers made of glucose subunits; starch stores energy and is made from photosynthesis, while glycogen is a large storage form found in animal livers
• Glycogen can be broken down into glucose subunits when animals need energy
• Cellulose is a polysaccharide that functions as a structural component of cell walls in plants
• Glucose units in cellulose are joined by an alternating up/down position of the oxygen atoms, making it indigestible by humans but necessary for good health
• Chitin, found in the exoskeleton of crabs, is another structural polysaccharide that can be used to make thread and as a suture material
• Maltose formation:

  • Maltose is formed by the combination of two glucose molecules
  • It is a disaccharide formed by a dehydration synthesis reaction, where a water molecule is released
• Phospholipid structure:

  • Similar to a fat molecule, but with a phosphate group instead of a third fatty acid chain
  • The phosphate group and fatty acid chains interact differently due to the polar and non-polar nature of the molecule
• Fat molecule formation:

  • A fat molecule is made by dehydration synthesis of glycerol and three fatty acid chains
  • Fats are hydrophobic and have non-polar tails that interact with each other, while the polar heads interact with water
• Fats are hydrophobic molecules with non-polar tails that interact with each other, while the polar heads interact with water
• The formation of a fat molecule involves dehydration synthesis of glycerol and three fatty acid chains
• Maltose formation is the condensation of 2 glucose molecules and is the simplest disaccharide
• The polar heads of a phospholipid are hydrophilic (they interact with inside and outside of cell). The tails (fatty acids) are non-polar and they interact with each other.
• Steroids have 4 adjacent rings but their attached groups differe
• Steroids can be a part of the cell's membrane function as a precursor of other steroids, bile salts, and sex hormones (testosterone + estrogen)
• Fats are oils functioning as energy storage molecules in organisms
• Phospholipids form a membrane that separates the cell from its environment and form its inner components.
• Lipids: part of cell membranes and help control what goes in and out of your cells.