A student investigated transpiration. Fig. 3.1 is a diagram of the apparatus used in the investigation. Fig. 3.1 - The student watered the plant before the investigation started. - She measured the mass of water lost every five minutes. - The mass of water lost represents the rate of transpiration. - She took measurements in still air and with a fan moving air past the plant. - $$$\quad$$$ She plotted her results on a graph as lines labelled $$$\mathbf{A}$$$ and $$$\mathbf{B}$$$. Fig. 3.2 shows the results. Fig. 3.2 Calculate the difference in the mass of water lost between the results for $$$\mathbf{A}$$$ and the results for $$$\mathbf{B}$$$ at $$$\mathbf{3 0}$$$ minutes. . g

Biology

IGCSE&ALevel

CAIE

Exam No：0610_w23_qp_31 Year：2023 Question No：3(b)(i)

Answer:

Knowledge points:

8.2.1 Identify root hair cells, as seen under the light microscope, and state their functions

8.2.2 State the pathway taken by water through root, stem and leaf as root hair cell, root cortex cells, xylem and mesophyll cells

8.2.3 Investigate, using a suitable stain, the pathway of water through the above-ground parts of a plant

8.2.4 Explain that the large surface area of root hairs increases the rate of the absorption of water by osmosis and ions by active transport

8.3.1 State that water is transported from the roots to leaves through the xylem vessels

8.3.2 Define transpiration as loss of water vapour from plant leaves by evaporation of water at the surfaces of the mesophyll cells followed by diffusion of water vapour through the stomata

8.3.3 Investigate and describe the effects of variation of temperature and humidity on transpiration rate

8.3.4 Explain how water vapour loss is related to the large surface area of cell surfaces, interconnecting air spaces and stomata

8.3.5 Explain the mechanism by which water moves upwards in the xylem in terms of a transpiration pull that draws up a column of water molecules, held together by cohesion

8.3.6 Explain how and why wilting occurs

8.3.7 Explain the effects of variation of temperature and humidity on transpiration rate

Answer:

Knowledge points:

Solution:

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