Chapter 9: plants as organism

• Endothermic


  Requiring heat energy
• Chlorophyll


  Green pigment in chloroplasts that absorbs light energy
• Chloroplast


  Organelle in plant cells where photosynthesis occurs
• Photosynthesis


  1. Absorption of light energy

  2. Conversion of light energy to chemical energy
• Adaptations of plants


  • Large surface area to absorb light energy
  • Air spaces to allow gas exchange
  • Veins to transport materials
• Limiting factors


  Anything that limits the rate of a reaction
• Temperature


  Affects the rate of photosynthesis
• At low temperatures, the rate of photosynthesis is lower due to reduced enzyme activity
• As temperature increases, the rate of photosynthesis increases
• At very high temperatures, enzymes are denatured and photosynthesis stops
• There is an optimum temperature for the maximum rate of photosynthesis
• Concentration/level of carbon dioxide increases as a plant respires faster
• When a plant doesn't respire, the carbon dioxide levels increase at night
• When light intensity increases in the morning, carbon dioxide is used up
• Controlling factors like environment (temperature, light intensity, carbon dioxide concentration) can give the fastest rates of photosynthesis and increase yield
• Temperature is maintained at optimum levels
• The glucose produced during photosynthesis is used for respiration, growth, and storage as starch
• Starch is the storage format of carbohydrates
• Plants produce cellulose to aid and strengthen cell walls
• Plants produce proteins made with amino acids
• Mineral ions and proteins are required for healthy plant growth and are absorbed against a concentration gradient
• Magnesium, nitrate, and phosphate are important mineral ions for plants
• Transpiration is the evaporation of water from the leaves and stems of a plant
• Transpiration creates a constant movement of water molecules through the xylem from the roots to the leaves
• Cohesion and adhesion of water molecules enables the transpiration stream
• Transpiration produces tension or 'pull' on the water in xylem vessels
• Companion cells


  Help keep sieve cells alive