Plants- Including Transpiration + Gas Exchange

Question 1

How root hair cells are adapted for their functions in the plant

Answer 1

• long
• increases surface area…
• to absorb:
• water…
• by osmosis
• minerals
• by diffusion
• active transport

Question 2

Potometer apparatus use for finding transpiration rate

Answer 2

• measure distance bubble moves
• (You can calculate volume by multiplying distance by area)
• use reservoir / gas syringe to reset the bubble
• repeats (to calculate mean)
• measure time (to calculate rate)

Question 3

Transpiration practical (5)

Answer 3

• (use) bubble potometer
• measure bubble movement
• measure for a stated time
• control abiotic factor (like light, temperature, humidity)
• repeat and obtain average

Question 4

Name factors that affect rate of transpiration

Answer 4

• light intensity
• temperature
• humidity
• wind speed
• co2 concentration
• size / mass / age / species of plant

Question 5

How do factors affect transpiration rate

Answer 5

• light intensity:
• stomata open
• more CO2 for photosynthesis
• more water vapor escapes (more transpiration)
• temperature:
• increases kinetic energy
• more evaporation from leaf cells
• faster water vapor diffusion
• humidity:
• air already has lots of water vapor
• less diffusion (less steep diffusion gradient)
• wind speed:
• wind removes moist air from around stomata
• wind blows water away
• keeps diffusion gradient steep
• soil water availability:
• dry soil means less water is absorbed
• stomata may close to prevent water loss
• CO2 concentration:
• affects stomata opening
• size / age / species / mass of plant:
• affects number of stomata

Question 6

Why is transpiration helpful to plants

Answer 6

• draws water up to leaves
• cooling
• minerals
• prevents wilting
• (water for) photosynthesis