Water and carbohydrates

• structure of water

  polar molecule structure. Water (H2O) has a slightly negative oxygen atom and slightly positive hydrogen atoms due to unequal charge distribution.
• Structure of water


  Structure of water

  
• dipole


  molecule which has partially positive and partially negative parts
• Hydrolysis reaction

  Reaction that requires water, and breaks down the chemical bonds of larger molecules into smaller components.
• Condensation reaction


  Reaction which joins monomer by chemical bonds and involve the elimination of a water molecule.
• Cohesion


  The attraction of molecules to other molecules of the same kind.

  The property of water molecules that allows them to stick together during hydrogen bonding

  cohesive allow good transport and flow.

  Eg: transpiration, transpiration transport of water and nutrients in plants

  Blood flow through narrow vessels in the cardiovascular system in animals
• Adhesion


  The attraction between unlike molecules.

  allows food transport as polar molecules can be dissolved and carried

  makes water a good solvent as substances are dissolved in it
• explain how of water is essential for living organisms

  dipolar nature means water molecules have both slightly positive and negative charges so they form hydrogen bonds with themselves and other similar molecules. Water can be used as a transport medium for all organisms as it adhesion makes it a solvent. The polar molecules can be transported for example water can carry oxygen and nutrients cells in the body.
• Carbohydrates


  Organic substances and a store of energy. It’s an organic molecule because it has carbon in a large amount. It contains carbon hydrogen and oxygen in the ratio 1:2:1
• Three main groups of carbohydrates

  1. Monosaccharides/single sugars- glucose, fructose, galactose
  2. Disaccharides/double sugars- sucrose, maltose, lactose
  3. Polysaccharides/many sugar units joined together- starch, glycogen, cellulose
• Monosaccharides/ single sugars


  monomer building blocks for more complex carbohydrates. sweet. Soluble in water and form crystals.

  classified by the number of carbon atoms

  General formula: CnH2nOn

  • triose (n=3) -glyceraldehyde
  • Pentose (n=5) -ribose, deoxyribose
  • hexose (n=6) -glucose,fructose
• Glucose chain formula


  Glucose chain formula

  
• Glucose ring structure’s (alpha and beta glucose)


  glucose ring structures

  
• Four monosaccharides

  1. Alpha glucose
  2. Beta glucose
  3. Fructose
  4. Galactose
• 4 monosaccharides and their roles

  Monosaccharides

  
• Drawing a glucose molecule

  Glucose molecule

  
• pentose sugars

  Ribose and deoxyribose pentose sugars have different chemical properties and biological roles
• Pentose sugars

  and deoxyribose have different chemical properties and biological roles

  
• Disaccharides structure


  Disaccharides

  
• What are disaccharides

  • formed from two monosaccharides joined by a glycosidic bond by a condensation reaction (removal of water between two hydroxyl groups)
  • ”double sugars”
  • Sweet and soluble.
• Examples of disaccharides

  1. Maltose (malt sugar) - formed from 2 glucose molecules by an alpha 1-4 glycosidic bond
  2. Sucrose (cane sugar) - glucose and fructose by alpha 1-4 glycosidic bond
  3. Lactose (milk sugar) - glucose and galactose by beta 1-4 glycosidic bond
• Polysaccharides

  • large insoluble molecules
  • Made of many (hundreds to thousands) of sugar unit e.g. glucose
  • Two types: storage or structural polysaccharides
  • Storage: starch, glycogen
  • Structural: cellullose
• What is starch?

  • Storage polysaccharide of plants
  • Stored as granules in plant cells
  • plants make glucose in photosynthesis, glucose molecules joint to make starch
  • Starch is constructed from two different polysaccharide
• What polysaccharides is starch constructed from?

  1. amylose

  • unbranched helix- coil/ spiral shaped chain
  • shape allows it to be more compact for more to be stored in plants
  • 1-4 glycosidic bonds between alpha glucose molecules

  1. amylopectin

  • branched - results in many terminal glucose molecules, easily hydrolysed providing glucose for use during cellular respiration or added for storage
  • 1-4 and 1-6 glycosidic bond between alpha glucose
• What is glycogen?

  • Storage polysaccharide of animals and bacteria.
  • Stored as granules and the liver
  • similar to starch but more branched
• Properties of starch


  • insoluble
  • Compact- can store a lot of glucose in small space
  • Doesn’t diffuse out of cell easily
  • Branching allows for quick hydrolysis- enzymes can break down branches quickly for glucose release
• Properties of glycogen

  • insoluble
  • Compact
  • Highly branched- allow rapid hydrolysis to release glucose quickly