transportation in plants

• What is the process by which plants manufacture carbohydrates using light energy?

  Photosynthesis
• Where does photosynthesis occur in plants?

  In chlorophyll
• What is the primary carbohydrate produced during photosynthesis?

  Glucose
• What happens to glucose after it is produced in photosynthesis?

  It is converted to sucrose for transport or starch for storage
• Why can't glucose be transported around the plant on its own?

  Because it is too reactive
• What is a limiting factor in photosynthesis?

  Something present in short supply that restricts life processes
• What would be the limiting factor if there is a shortage of carbon dioxide?

  Carbon dioxide itself
• What is the purpose of depriving a plant of chlorophyll, light, and carbon dioxide in an experiment?

  To prove that these factors are necessary for photosynthesis
• What is the first step in the experiment to test for starch in plants?

  De-starch the plants by leaving them in the dark for 48 hours
• What does a positive starch test indicate after the experiment?

  That photosynthesis has occurred
• What is the purpose of boiling the leaf in water during the starch test?

  To kill the leaf and make it permeable
• Why do we need to remove chlorophyll from the leaf before adding iodine?

  To make the color change from iodine easier to see
• How can you investigate the effect of light on photosynthesis?

  By partially covering the leaves and observing starch production
• What is the expected result when investigating the effect of light on photosynthesis?

  Covered areas will show a negative starch test
• How do you investigate the effect of carbon dioxide on photosynthesis?

  By using a carbon dioxide absorber with a test plant
• What result would indicate that carbon dioxide is a limiting factor in photosynthesis?

  The test plant shows a negative starch test
• How can you investigate the effect of chlorophyll on photosynthesis?

  By using a plant with variegated leaves
• What would you expect to find in a starch test of a variegated leaf?

  Parts with chlorophyll will show a positive result
• What are the effects of light intensity, carbon dioxide concentration, and temperature on the rate of photosynthesis?

  • Light intensity: Increases until it plateaus due to another limiting factor
  • Carbon dioxide concentration: Increases until it plateaus due to another limiting factor
  • Temperature: Increases until enzymes denature and the rate drops to zero
• What are the main structures of a leaf and their functions related to photosynthesis?

  • Cuticle: Waterproofs the leaf
  • Upper epidermis: Barrier against disease, allows light entry
  • Palisade mesophyll: Main site of photosynthesis, packed with chloroplasts
  • Spongy mesophyll: Allows gas exchange
  • Vascular bundle: Contains xylem and phloem for transport
  • Lower epidermis: Protective layer with stomata
  • Stomata: Controls gas exchange and transpiration
• What are the two important mineral requirements for plants?

  Nitrate ions and magnesium ions
• What role do nitrate ions play in plants?

  They are used in building amino acids
• What happens to a plant with a nitrate ion deficiency?

  Growth slows, stems weaken, and leaves turn yellow
• What is the role of magnesium ions in plants?

  They are required to make chlorophyll
• What are the effects of magnesium ion deficiency in plants?

  Leaves turn yellow and growth slows due to reduced photosynthesis
• What is the transport system in plants made of?

  • Xylem: Transports water, mineral ions, and solutes from roots to leaves
  • Phloem: Transports nutrients from leaves to the rest of the plant
• How do root hair cells aid in water absorption?

  They increase the surface area for absorption
• How does water move from the soil into the xylem?

  Through osmosis
• What factors contribute to water movement in the xylem?

  Transpirational pull, root pressure, and cohesion
• What is transpirational pull?

  Negative pressure at the top of the plant due to water leaving via transpiration
• What is root pressure?

  Positive pressure at the bottom of the plant due to water absorption
• How does cohesion affect water movement in the xylem?

  It allows water molecules to stick together, drawing the column of water up
• How does water enter the leaf for photosynthesis?

  Through the vascular bundle into palisade or spongy mesophyll cells
• What is transpiration?

  The loss of water vapor from leaves via the stomata
• What factors affect the rate of transpiration?

  Temperature and humidity
• How does temperature affect transpiration rate?

  Higher temperatures increase diffusion rate, thus increasing transpiration rate
• How does humidity affect transpiration rate?

  Higher humidity reduces diffusion rate, thus reducing transpiration rate
• What is translocation in plants?

  • Movement of sucrose and amino acids in the phloem
  • Source: Region of production
  • Sink: Region of storage or where they are used
• What is the source in the context of translocation?

  The region of production
• What is the sink in the context of translocation?

  The region of storage or where substances are used