photosynthesis

• Write the balanced symbol equation for photosynthesis. 

  6 C O₂  + 6 H₂ O ➔ C₆ H₁₂ O₆  + 6 O₂
• Plants need energy to produce glucose. 

  Where do plants get this energy from?

  The sun
• Which part of a plant cell absorbs the energy needed for photosynthesis?

  Chlorophyll
• Write down the word equation for photosynthesis

  Carbon Dioxide + Water ➔ Glucose + Oxygen
• Balance the symbol equation for photosynthesis

  6 CO₂  + 6 H₂O ➔ C₆H₁₂O₆  + 6 O₂
• Is photosynthesis an endothermic or exothermic reaction?

  Endothermic
• Give the uses of glucose:

  • Respiration
  • Can be converted into starch
  • Can be converted into cellulose for the cell wall
  • Can be converted into amino acids
  • Can be converted into lipids
  • Can be converted into sucrose
• Why is photosynthesis an endothermic reaction?

  It requires light energy
• What is photosynthesis?

  The process that plants and algae use to make glucose, requires carbon dioxide and water
• Facts about light needed in photosynthesis

  • The chlorophyll absorbs it
  • The chlorophyll are in chloroplasts
• Facts about water - reactant needed in photosynthesis

  • Absorbed by root hair cells in the soil
  • Absorbed by osmosis
  • Transported in the xylem to the leaves.
• Facts about carbon dioxide - reactant needed in photosynthesis

  •  It Diffuses into the leaf from the air
  • This happens via stomata.
• Facts about oxygen - product from photosynthesis

  • It diffuses out of the leaf from the air
  • It does this via stomata
• How are leaves well adapted for photosynthesis?

  • They are green so they contain a lot of chlorophyll
  • They are broad so there is an increased surface area for absorbing light
  • They are flat so there is a short distance for the diffusion of gases.
• What are the adaptations of the upper epidermis and what are their uses?

  It is transparent to allow light to pass through to palisade cells
• What are the adaptations of the spongy mesophyll and what are their uses?

  There are lots of air spaces to help carbon dioxide diffuse into palisade cells and oxygen to diffuse out of stomata
• What are the adaptations of palisade cells and what are their uses?

  lots of chloroplasts so more light can be absorbed for an increased rate of photosynthesis
• What are the adaptations of the veins of the plant and what are their uses?

  •  Xylem to transport water into palisade cells
  • Phloem to transport glucose away from the leaf
• What are the adaptations of the guard cells of the plant and what are their uses?

  open and close stomata to allow gas exchange but reduce transpiration.
• What are the factors that determine the rate of photosynthesis?

  • Light intensity
  • Temperature
  • Carbon Dioxide concentration
• Explain the role of carbon dioxide in photosynthesis and how increasing its concentration might affect the rate of photosynthesis.

  • carbon dioxide is one of the reactants required for photosynthesis
  • increasing the concentration of carbon dioxide increases the rate of photosynthesis up to a point
  • after this point other factors such as light intensity or temperature may become limiting
• What do you use to test if starch is present in a leaf?

  Iodine
• What would the positive results of the iodine test show?

  The presence of starch is highlighted in the colour blue or black
• What would the negative results of the iodine test show?

  It is highlighted in the colour yellow or brown