Question 1: Define transpiration in plants.

Answer: Transpiration is the process by which water vapour is lost from the plant mainly through the stomata in the leaves.

Question 2: Describe how the structure of leaf stomata facilitates transpiration.

Answer: Stomata are small pores surrounded by guard cells that can open and close, allowing water vapour to diffuse out when open, thereby facilitating transpiration.

Question 3: Explain why transpiration is important for plants.

Answer: Transpiration helps in cooling the plant, maintaining water flow from roots to leaves, and enabling the uptake of minerals from the soil.

Question 1: Calculate the transpiration rate if 600 grams of water is lost over 12 hours. Express your answer in grams per hour.

Answer: Transpiration rate = 50 grams per hour

Question 2: If a plant has a surface area of 0.5 m² and loses 200 grams of water in 4 hours, what is the rate of transpiration per square metre per hour? (Show your working.)

Answer: Transpiration rate = 100 grams per square metre per hour

Question 1: Describe a simple experiment to measure the rate of transpiration in a plant. Include the variables you would control, the variables you would measure, and safety precautions.

Answer: An experiment can involve covering a plant with a sealed, transparent bag to collect water vapour or using a potometer. Control variables include temperature, humidity, and light intensity. Measure the amount of water lost over time. Safety precautions include handling equipment carefully and avoiding damage to the plant.

Question 1: A plant exposed to high light intensity shows an increased rate of water loss compared to the same plant in low light. Explain the physiological reasons for this observation.

Answer: High light intensity causes the stomata to open wider to facilitate gas exchange, increasing water vapour loss through transpiration.

Question 1: Discuss how understanding transpiration can help improve irrigation practices in agriculture. Include potential benefits and challenges.

Answer: Understanding transpiration helps optimise watering schedules to prevent water wastage and ensure adequate water supply. Benefits include increased crop yield and water conservation. Challenges involve variability due to weather conditions and plant species differences.