Chapter 4

• Elements - are substances that cannot be broken into simpler substances by chemical changes
• SOME COMMON ELEMENTS FOUND IN PLANTS:

  1. Carbon
  2. Oxygen
  3. Hydrogen
  4. Nitrogen
  5. Phosphorus
  6. Potassium
  7. Magnesium
  8. Iron
  9. Calcium
• Carbon - Backbone of organic molecules
• Oxygen - Present in most organic molecules and required for aerobic respiration
• Hydrogen - Present in most organic molecules
• Nitrogen - Present in all proteins and nucleic acids, also present in chlorophyll
• Phosphorus - Present in nucleic acids and energy transfer molecules such as ATP
• Potassium - Helps provide ionic balance in cells
• Magnesium - Present in chlorophyll
• Iron - Component of certain enzymes
• Calcium - Constituent of cell walls
• Atom - Smallest possible particle of an element
• Proton - positive charge
• Neutron - uncharged particle
• Electron - negative charge
• Chemical Bonds - attractive force that holds two or more atoms together in a compound
• Ionic bond - Force of attraction between two oppositely charged ions
• Ions - atom w/ negative or positive electric charge
• Covalent Bond - when two atoms share a pair of electrons to complete their outermost energy levels
• molecule - When to or more atoms join one another by covalent bonding and the smallest unit of covalent compound
• Inorganic Substances - Compound that do not contain carbon and the substances taken into the cell from the outside. Also, ionic bonding is present
• Water - Most important inorganic compound in the cell
• Water:

  • Making up more than 90% of the fresh weight of the cytoplasm
  • Solvent that dissolves ions and molecules entering and leaving the cell
  • One of the raw materials needed for photosynthesis
  • Provides pressure needed for the maintenance of cell form
  • Absorbs heat
• Carbon Dioxide - Raw material for photosynthesis
• Oxygen - Raw material for cellular respiration
• Mineral salts - Compound formed when an acid is neutralized by a base
• Mineral Salt:

  • Found in the cell in very small amounts
  • Very essential for the growth of plants
  • Serves as raw material together with CO2 and water that is used to synthesize that many complex organic materials in the cell
  • Maintains osmotic pressure and acid-base balance
• Organic Substance - Carbon-containing compounds that are synthesized by the living cell from inorganic raw materials. Also, contains covalent bonding.
• Carbohydrates - Organic compound containing carbon, hydrogen, and oxygen atoms with general formula (CH2O)n. Also, the main source of cellular energy
• Monosaccharides - Simple sugars
• Hexose - most important monosaccharide
• Glucose and fructose - hexose that are common in plants
• Disaccharides - Double sugars
• Sucrose - most abundant disaccharides in plants which is composed of glucose and fructose molecule
• Maltose - composed of two glucose molecules occurs in a free state only to a limited extent, but may readily be obtained by the hydrolysis of starch
• Polysaccharides - Union of many simple sugars
• Cellulose and Starch - Two most abundant polysaccharides in plants
• Cellulose - major structural material in the cell wall
• Starch - reserved water-insoluble food that is stored in many cells
• Lipids - Storage form of energy