Paper 2

• What do root hairs do in plants?

  They take in water and minerals from the soil.
• Why do root hairs grow into long "hairs"?

  To increase the surface area for absorbing water from the soil.
• How many root hairs cover each branch of a root?

  Millions of microscopic hairs.
• How do root hair cells take in minerals?

  By active transport.
• How is water taken in by root hair cells?

  Through osmosis.
• Why does water move into root hair cells by osmosis?

  Because there is usually a higher concentration of water in the soil than inside the plant.
• What is the function of the xylem in plants?

  To transport water from the roots to the leaves.
• What happens to a house plant if it is not watered for a few days?

  It starts to droop and may die.
• What is transpiration?

  The loss of water from the plant.
• What causes transpiration in plants?

  Evaporation and diffusion of water from the plant's surface.
• Where does most transpiration occur in a plant?

  At the leaves.
• What effect does evaporation have on water levels in leaves?

  It creates a slight shortage of water, drawing more water up from the rest of the plant.
• What is the relationship between transpiration and water uptake in plants?

  Water uptake is directly related to water loss by the leaves.
• Why do leaves have stomata?

  To allow for gas exchange during photosynthesis.
• How does light intensity affect transpiration rate?

  The brighter the light, the greater the transpiration rate.
• What happens to stomata at night?

  They begin to close as it gets darker.
• How does temperature affect transpiration?

  The warmer it is, the faster transpiration happens.
• How does wind speed influence transpiration rate?

  The higher the wind speed, the greater the transpiration rate.
• What effect does humidity have on transpiration?

  The drier the air around a leaf, the faster transpiration happens.
• What are the four main factors affecting transpiration rate?

  1. Light intensity
  2. Temperature
  3. Wind speed
  4. Humidity
• what can be to estimate transpiration rate?


  a potometer
• what is a potometer?

  a piece of aparatus that measures water uptake by a plant,
• What is the first step in using a potometer?

  Cut a shoot underwater to prevent air from entering the xylem
• Why should the shoot be cut at a slant when using a potometer?

  To increase the surface area for water absorption
• What should you do after assembling the potometer in water?

  Insert the shoot underwater to prevent air from entering
• What is the purpose of keeping the end of the capillary tube submerged in a beaker of water?

  To ensure no air can enter the system
• What should you check for after removing the potometer from the water?

  That it is airtight and watertight
• What should you do after drying the leaves of the shoot?

  Allow time for the shoot to acclimatize and then shut the tap
• What is the purpose of removing the end of the capillary tube until one air bubble forms?

  To create a starting point for measuring the distance moved by the bubble
• What should you do after recording the air bubble's starting position?

  Start a stopwatch and record the distance moved by the bubble per unit time
• Why is it important to keep the conditions constant throughout the experiment?

  To ensure accurate and reliable results
• what are some factors you could test using a potometer?


  • light intensity
  • temperature
  • humidity
  • wind speed