Biological molecules

• What is a monomer?


  A single molecule from which larger molecules are made
• What is a polymer?

  A chain of monomers
• How are polymers formed?

  Through condensation reactions
• What is a condensation reaction?

  A reaction that joins monomers together, forming a bond and releasing water
• How are polymers broken down into monomers?

  Through hydrolysis reactions
• What is a hydrolysis reaction?

  A reaction in which a bond is broken by the addition of a water molecule
• What is the definition of metabolism?

  The total sum of all chemical reactions in an organism
• What are the two types of metabolic reactions?

  Catabolic and anabolic reactions
• What are monosaccharides?


  Single sugar monomers; they are the simplest carbohydrates
• What are some examples of common monosaccharides?

  Glucose, galactose, and fructose
• What are the two forms of glucose?

  Alpha glucose and beta glucose
• How can we tell if glucose is alpha or beta?


  By the position of the hydroxyl group on carbon 1 (below for alpha, above for beta)
• How do disaccharides form?

  When two monosaccharides chemically react together in a condensation reaction
• What is the new bond formed called in the reaction between two monosaccharides?

  A glycosidic bond
• What monosaccharides make up sucrose?

  Glucose and fructose
• What monosaccharides make up lactose?

  Glucose and galactose
• What monosaccharides make up maltose?

  Glucose and glucose
• What is the structure of glycogen?

  A branched large polysaccharide molecule that is insoluble in water
• What is the structure of starch?

  A helical large polysaccharide molecule that is insoluble in water
• What is the structure of cellulose?


  Every other beta glucose molecule is inverted, with lots of hydrogen bonds linked to form strong fibers
• What is the test for starch?

  Iodine solution, which turns blue-black if positive and orange-yellow if negative
• What is the test for protein?

  Biuret solution, which turns purple if positive and remains blue if negative
• What is the test for lipids?

  Ethanol and water, which produces a white emulsion
• What is the test for reducing sugars?

  Benedict's test, which turns brick red if reducing sugars are present
• How do you test for non-reducing sugars?

  Heat with Benedict's; if negative, hydrolyze with HCl, neutralize with NaOH, and heat again
• What is the main function of starch?


  Major carbohydrate storage of plants
• What is the main function of cellulose?

  Provides strength and structural support to plant cell walls
• What is the main function of glycogen?


  Major carbohydrate storage for animals
• What characteristic of polysaccharides is important for them to do their jobs?

  They are insoluble in water, meaning they don't affect water potential and can't diffuse out of cells
• What two polysaccharides make up starch?

  Amylose and amylopectin
• What are five roles of lipids?

  Contribute to cell membrane flexibility, source of energy, waterproofing, insulation, and protection
• What are triglycerides made of?

  Three fatty acids and one glycerol
• What is a phospholipid?


  A type of lipid where one of the fatty acids is replaced by a phosphate group
• What bonds hold lipids together?

  Ester bonds
• What is the monomer of proteins?

  Amino acids
• What are two amino acids bonded together called?

  A dipeptide
• What bond holds proteins together?

  A peptide bond
• What is a polypeptide?


  Many amino acids joined together
• What is one or more polypeptides called?

  A protein
• What elements make up proteins?

  Carbon, hydrogen, oxygen, and nitrogen