(a)
Explain why active transport is important in root hair cells.
[ 3 ]
[Maximum number: 3]
Fig. 1.1 shows several villi from the ileum, which is part of the small intestine.
(a)
Fig. 1.2 shows the tip of a villus in more detail.
Fig. 1.2
The epithelial cells of the villi absorb nutrients by diffusion and active transport.
[ 3 ]
(i)
Describe how active transport differs from diffusion.
[ 3 ]
[Maximum number: 1]
Some examples of substances moving across membranes are listed.
1 glucose molecules into the epithelium that lines the small intestine
2 nitrate ions from a dilute solution in soil into a more concentrated solution in root hair cells
3 water molecules from mesophyll cells into the air spaces of a leaf
For which examples must oxygen be present?
A
1, 2 and 3
B
1 and 2 only
C
1 and 3 only
D
2 and 3 only
[Maximum number: 1]
Which process requires energy from respiration?
A
active transport
B
diffusion
C
osmosis
D
transpiration
[Maximum number: 1]
Which diagram represents active transport?
C
does not require energy from respiration
D
does not require energy from respiration
[Maximum number: 1]
Which statement about diffusion is correct?
A
The process requires energy from respiration.
B
The particles must cross a cell membrane.
C
The net movement of particles is up a concentration gradient.
D
The process involves the random movement of particles.
[Maximum number: 1]
Which is an example of active transport?
A
carbon dioxide entering a leaf
B
ion uptake by root hair cells
C
oxygen moving from the alveoli into the blood
D
water uptake by root hair cells
[Maximum number: 1]
Which process is involved in the uptake of glucose by the epithelial cells of kidney tubules?
A
active transport
B
diffusion
C
osmosis
D
transpiration
[Maximum number: 1]
The diagram shows a root hair cell.
Why does a root hair cell contain a large number of mitochondria?
A
to provide energy for the absorption of water from the soil
B
to provide energy for the diffusion of mineral ions from the soil
C
to provide energy for osmosis
D
to provide energy for the active transport of mineral ions from the soil
[Maximum number: 1]
What is not an example of active transport?
A
absorption of water by root hairs
B
reabsorption of glucose by kidney tubules
C
uptake of glucose by villi
D
uptake of ions by root hairs