TRANSPORT IN PLANTS

• Structure of a Leaf

  
• Guard Cells

  
• Measuring Water Uptake by a Leafy Shoot Using a Potometer

  
• What is the function of the epidermis in plants?

  Protection of the outer surfaces
• Which tissue is the main site of photosynthesis in the leaf?

  Palisade mesophyll
• What is the purpose of the air spaces in the spongy mesophyll?

  Allow gases to diffuse through the leaf
• What do xylem vessels transport through a plant?

  Water and minerals
• What additional function do xylem vessels provide to the plant?

  Supports the plant
• What do phloem vessels transport through a plant?

  Dissolved food materials
• Where is meristem tissue mainly found in a plant?

  Tips of roots and shoots
• What is the function of meristem tissue?

  Produce new cells for growth
• What do plant tissues form?

  Organs
• Why are many chloroplasts located close to the top of the leaf?

  To trap maximum sunlight
• Why are there lots of air spaces in the leaf?

  To allow gases to diffuse
• What is the role of stomata in the leaf?

  Allow diffusion of gases
• What cells control the opening and closing of stomata?

  Guard cells
• Through what cell does water enter the plant?

  Root hair cells
• How does water enter the plant from the soil?

  Osmosis
• What does the water contain that is transported in the xylem?

  Dissolved minerals
• Where does the water and minerals travel after entering the roots?

  To the stems and leaves
• What happens to most of the water at the leaves?

  Evaporates and diffuses out
• What is the loss of water from the leaves called?

  Transpiration
• What are the small pores called that water diffuses out of?

  Stomata
• How does transpiration aid in water transport?

  Draws water up xylem vessels
• How does an increase in temperature affect the rate of transpiration?

  Increases the rate
• How does faster air flow affect the rate of transpiration?

  Increases the rate
• How does increased light intensity affect the rate of transpiration?

  Increases the rate
• How does increased humidity affect the rate of transpiration?

  Decreases the rate
• What is the role of guard cells in the leaf?

  Open and close stomata
• Why are stomata closed at night?

  Reduce water loss
• What happens when guard cells take up water?

  Stomata open
• What happens when water is scarce in guard cells?

  Stomata close
• Where are stomata mainly found on the leaf?

  Bottom surface
• Why are stomata mainly on the bottom surface of the leaf?

  To reduce water loss
• How can the rate of transpiration from a cut shoot be estimated?

  Rate shoot takes up water
• Why is measuring water uptake only an estimate of transpiration?

  Some water is used
• What tissue transports dissolved sugars from the leaves?

  Phloem tissue
• What is the movement of food through phloem tissue called?

  Translocation
• How are xylem and phloem cells specialized to transport water, minerals, and sugars?

  • Xylem: dead cells forming continuous tubes for efficient water and mineral transport, thickened walls for support.
  • Phloem: living cells with sieve plates allowing sugar solutions to flow, companion cells provide energy.
• Why does increased light intensity increase the rate of transpiration?

  Causes stomata to open