Plant Systems (Gas Exchange and Transport Systems)

• Describe the role of stomata and guard cells?

  Carbon dioxide and oxygen move in and out of leaves through openings called stomata. Guard cells control the opening and closing of stomata.
• Explain how the leaf facilitates gas exchange.

  The exchange of oxygen, carbon dioxide and water in transpiration, occur by the stomata.
• What properties make plant cells optimal for photosynthesis?

  Spongy and palisade mesophyll, epidermis, cuticle, and vascular bundles.
• What does the spongy mesophyll do?

  Allows for the movement of gas.
• What does the palisade mesophyll do?

  Contains chloroplast that allow for photosynthesis to occur.
• What does the epidermis of a plant do?

  A layer of protection.
• What does the cuticle do?

  Is impermeable to water, therefore prevents the loss of necessary water.
• What does the vascular bundles do?

  Include the xylem and phloem, transporting all important substances.
• What does the xylem do?

  Xylem transports and stores water. It allows for the water to travel up and is considered dead.
• What does the phloem do?

  The phloem is responsible for transporting sugars, proteins, and other organic molecules in plants. They allow for the substances to travel to all areas around the plant. Has sieves that controls the travel of the sugars.
• Explain how water and dissolved minerals move through the xylem.

  During transpiration, the evaporation of water leaves a negative water potential gradient causes water to move up through the xylem.
• How does a higher temperature effect transpiration?

  Increases transpiration rate.
• How does a higher humidity affect water loss in transpiration?

  Will decrease transpiration rates.
• Explain translocation?

  Translocation occurs in the phloem tissue, which consists of phloem vessels. These phloem vessels run from the leaves into every other part of the plant and are responsible for transporting dissolved organic solutes, such as sucrose and amino acids, from the sources to the sinks.