1.4 Membrane transport [66
marks]
1. What is/are required for facilitated diffusion? [1 mark]
I. A concentration gradient
II. ATP
III. A channel protein
A. I only
B. I and III only
C. II and III only
D. I, II and III
,2. In an experiment on osmosis, red blood cells were immersed in a salt [1 mark]
solution for two hours. The micrographs show the appearance of these
cells before and after immersion in the salt solution.
[Source: Ed Uthman, Acanthocytes, from peripheral blood [image online] Available
at:
https://en.wikipedia.org/wiki/Acanthocyte#/media/File:Acanthocytes,_Peripheral_Blood_
This file is licensed under the Creative Commons Attribution 2.0 Generic (CC BY
2.0) https://creativecommons.org/licenses/by/2.0/ Source adapted.]
What explains the observed changes?
A. The salt solution was hypertonic and entered the red blood cells.
B. The salt solution was hypotonic and disrupted the membranes of the red blood
cells.
C. The salt solution was hypertonic and water moved into it from the red blood
cells.
D. The salt solution was hypotonic and mineral salts were lost from the red blood
cells.
, 3. Which feature(s) allow(s) transport of glucose in blood plasma? [1 mark]
I. It is hydrophobic.
II. It is polar.
III. Its solubility is low at 37 °C.
A. I only
B. II only
C. I and II only
D. II and III only
4. How is facilitated diffusion in axons similar to active transport? [1 mark]
A. They both require the energy of ATP.
B. They both move substances against a concentration gradient.
C. They both use sodium–potassium pumps.
D. They are both carried out by proteins embedded in the axon membrane.
marks]
1. What is/are required for facilitated diffusion? [1 mark]
I. A concentration gradient
II. ATP
III. A channel protein
A. I only
B. I and III only
C. II and III only
D. I, II and III
,2. In an experiment on osmosis, red blood cells were immersed in a salt [1 mark]
solution for two hours. The micrographs show the appearance of these
cells before and after immersion in the salt solution.
[Source: Ed Uthman, Acanthocytes, from peripheral blood [image online] Available
at:
https://en.wikipedia.org/wiki/Acanthocyte#/media/File:Acanthocytes,_Peripheral_Blood_
This file is licensed under the Creative Commons Attribution 2.0 Generic (CC BY
2.0) https://creativecommons.org/licenses/by/2.0/ Source adapted.]
What explains the observed changes?
A. The salt solution was hypertonic and entered the red blood cells.
B. The salt solution was hypotonic and disrupted the membranes of the red blood
cells.
C. The salt solution was hypertonic and water moved into it from the red blood
cells.
D. The salt solution was hypotonic and mineral salts were lost from the red blood
cells.
, 3. Which feature(s) allow(s) transport of glucose in blood plasma? [1 mark]
I. It is hydrophobic.
II. It is polar.
III. Its solubility is low at 37 °C.
A. I only
B. II only
C. I and II only
D. II and III only
4. How is facilitated diffusion in axons similar to active transport? [1 mark]
A. They both require the energy of ATP.
B. They both move substances against a concentration gradient.
C. They both use sodium–potassium pumps.
D. They are both carried out by proteins embedded in the axon membrane.
