Question 6
[Maximum number: 1]
Why do some root cells have root hairs?
A
for the maintenance of the temperature of the cell sap
B
to increase the surface area of the cells
C
to increase the volume of the cell sap
D
to provide a place for cell nuclei
IGCSE Biology Extended 8.2.2—Large surface area of root hairs Topic Practice
8.2.2—Large surface area of root hairs
• State that the large surface area of root hairs increases the uptake of water and mineral ions
Question 16
[Maximum number: 1]
How is the structure of root hair cells related to their function?
A
They have chloroplasts for photosynthesis.
B
Their cell wall is partially permeable to absorb water by osmosis.
C
They have a large surface area to increase the rate of mineral ion uptake.
D
Both the cell wall and cell membrane control the active uptake of mineral ions.
Question 3(c)(i)
[Maximum number: 2]
Fig. 3.1 shows a photomicrograph of a section of a root.
Fig. 3.1
Scientists wanted to determine the flow-rate of water in roots.
They measured the flow-rate in three zones of onion roots as shown in Fig. 3.2.
Fig. 3.2
They measured the flow-rate in healthy roots and roots that had been treated with a toxic solution.
Their results are shown in Table 3.1.
Table 3.1
Calculate the percentage increase in the average flow-rate between zone 1 and 3 for healthy roots.
Give your answer to two significant figures.
Show your working.