Biology Topic 1

• Monomer


  Smaller units which can create larger molecules
• Polymer


  Molecule made up of smaller units called monomers chemically bonded together
• Monomer of amino acid


  Makes polymer of protein
• Monomer of glucose


  Makes polymers of starch, cellulose, glycogen
• Monomer of nucleotide


  Makes polymers of DNA and RNA
• Condensation reaction


  Joining two molecules together, creating a chemical bond, removing a water molecule
• Hydrolysis reaction


  Breaks a chemical bond between two molecules and involves the use of a water molecule
• Monosaccharides


  glucose, fructose, galactose
• Disaccharides


  sucrose, maltose, lactose
• Polysaccharides


  starch, cellulose, glycogen
• Alpha glucose


  OH on bottom
• Beta glucose


  OH on top
• Isomers


  Same molecular formula, different structural formula
• Disaccharides are made up of

  - 2 monosaccharides

  - joined together by a glycosidic bond
• Glucose + glucose


  Maltose + water
• glucose + galactose


  lactose + water
• Glucose + fructose


  sucrose + water
• role of starch in plant cells

  Storage of glucose for energy in plants
• Role of cellulose in plants


  Provides structural strength in cell wall
• Glycogen role


  Storage of glucose for energy in animals (liver and muscle cells)
• Monomer of cellulose


  beta glucose
• Monomer of starch


  Alpha glucose
• Monomer of glycogen


  Alpha glucose
• Structure of starch


  - amylose and amylopectin

  - amylose is an unbranched helix

  - amylopectin is a branched molecule
• How does structure lead to function of starch

  Helix is compact so can fit a lot of glucose in a small space. Branched structure increases surface area for rapid hydrolysis back to glucose. Insoluble so won't effect water potential
• Structure of cellulose


  - polymer forms long straight chains

  - chains are held parallel by many hydrogen bonds to form fibrils
• Structure of glycogen


  Highly branched molecule to increase surface area, allowing for rapid hydrolysis back to glucose. Insoluble so won't effect water potential
• Triglyceride structure


  Glycerol backbone and 3 fatty acids
• Phospholipids structure


  Glycerol backbone, 2 fatty acids, phosphate group
• Formation of triglycerides


  Three condensation reactions between the fatty acids and the glycerol. 3 water molecules lost. Forms ester bonds
• Saturated fatty acid


  Hydrocarbon chain contains only single bonds between carbons
• Unsaturated fatty acid


  Hydrocarbon chain consists of at least one double bond between carbon atoms
• Properties of triglycerides


  - energy storage due to high ratio of energy-storing carbon-hydrogen bonds

  - high ratio of hydrogen to oxygen atoms, metabolic water source

  - insoluble in water, do not affect water potential
• Formation of phospholipids


  Two fatty acids bond to the glycerol via two condensation reactions, resulting in two ester bonds
• Properties of phospholipids


  - hydrophilic heads due to negative charge on phosphate group

  - attracts water and repels fats as it is charged

  - fatty acid know as the hydrophobic tail repels water but will mix with fats
• How many different amino acids

  20
• Dipeptides


  Formed when two amino acids join by a condensation reaction
• Polypeptides


  Formed by the condensation of many amino acids
• Primary protein structure


  The order of the amino acids in the polypeptide chain
• Secondary protein structure


  The sequence of amino acids causes parts of a protein to bend into an alpha helix or fold into a beta pleated sheet. Hydrogen bonds hold the structure together