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Complete the sentence by putting a cross (X) in the box next to your answer - Edexcel - GCSE Biology - Question 3 - 2012 - Paper 1
Question 3
Complete the sentence by putting a cross (X) in the box next to your answer. Plants lose water, into the air, by a process called __________ A active transport B ... show full transcript
Worked Solution & Example Answer:Complete the sentence by putting a cross (X) in the box next to your answer - Edexcel - GCSE Biology - Question 3 - 2012 - Paper 1
Step 1
Step 2
Complete the sentence by putting a cross (X) in the box next to your answer.
Answer
The maximum mass of water lost from the plant in this investigation was 32 g (option B), calculated as follows:
Mass lost = mass after investigation - mass before investigation Mass lost = 115 g - 90 g = 25 g at 25 °C, and similarly for others, with the maximum being 32 g.
Step 3
Describe the effect of temperature on water loss from this plant during the investigation.
Answer
Temperature affects water loss from the plant significantly. As the temperature increases, the rate of transpiration tends to rise. Initially, from 15°C to 35°C, water loss increases; however, at 45°C, there is a slight decrease in water loss compared to 35°C. This suggests that while higher temperatures promote transpiration, extreme heat may cause stress or damage to plant tissues, resulting in reduced water loss.
Step 4
Suggest why the plastic bag was placed around the plant pot during this investigation.
Answer
The plastic bag was likely placed around the plant pot to:
- Prevent evaporation/loss of water from the soil.
- Ensure that the mass of calcium chloride only changed due to water loss from the plant and not from the soil.
- Maintain the validity of the investigation, making it fair and reliable.
Step 5
Explain how glucose production could be affected if this plant lost a lot of water.
Answer
If the plant loses a significant amount of water, its ability to photosynthesize may be compromised. Water is a crucial reactant in photosynthesis; a lack of water can lead to stomatal closure to reduce water loss, which in turn limits CO2 intake necessary for glucose production. Consequently, the plant's overall glucose output could decrease, affecting its growth and energy storage.
Step 6
Describe the process that moves water from the soil into the plant.
Answer
Water moves from the soil into the plant primarily through the process of osmosis. Osmosis is the movement of water from an area of lower solute concentration (the soil) to an area of higher solute concentration (the root cells of the plant) across a semi-permeable membrane. As water enters the roots, it travels through the xylem vessels to reach the leaves, where it is used for photosynthesis or lost through transpiration.