Syllabus Edition
First teaching 2023
First exams 2025
The diagram represents three possible pathways through a cell surface membrane.
Which process is represented by each arrow?
| 1 | 2 | 3 | |
|
A |
facilitated diffusion | diffusion | active transport |
| B | active transport | diffusion | facilitated diffusion |
| C | facilitated diffusion | active transport | diffusion |
| D | active transport | facilitated diffusion | diffusion |
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Which mode of transport is energy independent?
diffusion
active transport
exocytosis
endocytosis
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Complete the sentence:
“Plasmolysis occurs when a(n) ____X____ cell is immersed in a _____Y_____ solution.”
| X | Y | |
| A | animal cell | pure water |
| B | animal cell | strong saline |
| C | plant cell | pure water |
| D | plant cell | strong saline |
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Cells require the following molecules for normal functioning:
Which molecules require a protein for transport across the cell surface membrane?
1 only
1 and 3
1, 2 and 4
1, 2, 3 and 4
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What form of cellular transport is shown in the diagram above?
exocytosis
facilitated diffusion
protein pump
endocytosis
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The following are all examples of cellular transport:
|
1 |
bacterium engulfed by phagocytes |
|
2 |
digestive enzymes being secreted from the pancreas |
|
3 |
an egg cell taking up liquid nutrients from follicle cells |
|
4 |
the release of neurotransmitters from the presynaptic neuron |
Which examples require bulk transport?
1 and 2
1 and 3
1, 2 and 4
1, 2, 3 and 4
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Which of the following statements regarding membrane transport is false?
a protein channel is specific to one type of solute
proteins are not transported across cell membranes
polar and charged solutes will not cross the cell membrane
glucose is always actively transported by protein carriers
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“Diffusion is a result of…”
Which option correctly completes the sentence?
cellular energy forcing molecules to collide with each other.
cellular energy moving molecules across a partially permeable membrane.
molecules constantly moving and colliding with each other.
molecules being attracted to each other.
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Substance X moves through a protein channel into a cell.
Which statement best describes substance X and it’s movement?
oxygen moving via osmosis down its concentration gradient
glucose moving via diffusion down its concentration gradient
sodium ion moving via active transport against its concentration gradient
chloride ion moving via facillitated diffusion down its concentration gradient
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The movement of water is dependent on the water potential either side of a partially permeable membrane.
What is the correct equation for calculating the total water potential (Ψ) from solute potential (Ψs)and pressure potential (Ψp)?
Ψs × Ψp = Ψ
Ψs ÷ Ψp = Ψ
Ψs + Ψp = Ψ
Ψs – Ψp = Ψ
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A student places an animal cell and a plant cell into distilled water and notes down the following observations.
Animal cell: swells then bursts
Plant cell: swells
What is the reason for this difference?
plant cell surface membranes are partially permeable
animal cells have no vacuole
animal cells have no cell wall
plant cell walls are freely permeable
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The water potential of sea water is approximately –2500 kPa. Halophytes are plants that are able to survive in regions where they are regularly exposed to sea water.
Which adaptation would you expect halophytes to have to enable them to live in this environment?
root hair cells with a very high water potential
leaves that have a large surface area and a thick cuticle
root hair cells which accumulate salts and other solutes
a high density of stomata that are open most of the time
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A model to demonstrate the mass flow hypothesis of translocation is illustrated in the diagram.
In a plant, what are the structures W, X, Y and Z and what is the direction of flow of solution along X?
| phloem | xylem | roots | leaves | direction of flow along X | |
| A | W | X | Y | Z | from Y to Z |
| B | W | X | Z | Y | from Y to Z |
| C | X | W | Y | Z | from Z to Y |
| D | X | W | Z | Y | from Z to Y |
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An artificial partially permeable membrane called visking tubing can be used to demonstrate diffusion. The pores in the membrane are approximately 2.4 nm in diameter which allows glucose molecules to pass through.
Which of the following could pass through the pores?
1 and 4 only
3 only
2 and 3 only
none of these
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Some viruses bind to the cell surface membrane before entering the host cell.
Which sequence of events results in a viral invasion of a cell?
binding to the hydrophilic part of a phospholipid, followed by exocytosis
binding to a glycoprotein receptor, followed by exocytosis
binding to a protein receptor, followed by endocytosis
binding to a cholesterol molecule, followed by endocytosis
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The diagram represents the phloem pathway and adjacent cells from leaf to root in a plant.
What process is occurring between 1 to 2 and what is the effect on the water potential at 2?
| process from 1 to 2 | water potential at 2 | |
| A | active transport of sucrose | becomes less negative |
| B | active transport of sucrose | becomes more negative |
| C | diffusion of sucrose | becomes less negative |
| D | diffusion of sucrose | becomes more negative |
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Diagrams 1, 2 and 3 show red blood cells in different states after each being submerged in a different solution.
What is the correct order of the water potential of each solution from lowest to highest?
1 < 2 < 3
3 < 1 < 2
2 < 3 < 1
2 < 1 < 3
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Various factors affect the rate of diffusion of molecules.
Which conditions would result in the fastest rate of diffusion?
|
difference in concentration |
temperature (°C) |
surface area : volume ratio |
molecule | |
| A | 1 | 25 | 4 | sodium |
| B | 5 | 15 | 2 | glucose |
| C | 10 | 35 | 0.5 | water |
| D | 20 | 20 | 3 | oxygen |
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Which of the following membrane proteins does not undergo a conformational change to perform its function?
voltage gated aquaporin
sodium-glucose symporter
ATP-ase proton pump
non-gated channel protein
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Two solutions are separated by a partially permeable membrane. The two solutions have a different concentration of glucose (black dots).
Which of the following best describes what will happen to the amount of glucose, volume of water and concentration of solution?
| Solution | Amount of glucose | Volume of Water | Concentration | |
| A |
1 2 |
remains constant remains constant |
decreases increases |
increases decreases |
| B |
1 2 |
increases decreases |
remains constant remains constant |
increases decreases |
| C |
1 2 |
remains constant remains constant |
increases decreases |
decreases increases |
| D |
1 2 |
decreases increases |
increases decreases |
remains constant remains constant |
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The fluidity of the cell surface membrane can be altered by a variety of factors.
Which process would be least changed if the fluidity of cell surface membranes is decreased?
endocytosis
osmosis
diffusion
active transport
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The diagram shows an experiment constructed by a student to measure the water potential of beetroot cells. The results are shown in the table below.
| Concentration of sucrose solution (mol dm-3) | Water potential of sucrose solution (kPa) | Direction and Speed of Droplet Movement |
| 0.1 0.2 0.3 0.4 0.5 0.6 0.7 |
-251 -1876 |
down, very quickly down, quickly down, slowly laterally up, slowly up, quickly up, very quickly |
What is the water potential of the beetroot cells?
-251
-793
-1083
-1876
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An aerobic cell stops responding to growth regulation signals, causing the volume of the cytoplasm to increase and the cell to grow. Eventually the cell dies.
Which of the following cell transport methods affects cell growth?
|
1 |
diffusion |
|
2 |
active transport |
|
3 |
exocytosis |
|
4 |
osmosis |
1 only
1 and 4 only
2 and 3 only
1, 2 and 3 only
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An experiment to calculate the water potential of potato was performed using the following protocol:
The mean weight of the potato cubes was 2.5g before being added to solution and the graph shows the weights of potato cubes after the experiment.
What concentration of sucrose has the same water potential as the potato?
0 M
0.12 M
0.31 M
0.66 M
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Two agar blocks of different sizes are produced and universal indicator is added, making the agar turn purple.
The cubes are then placed in hydrochloric acid solution. Universal indicator turns red in acid. After 10 minutes, the amount of agar that has turned red is measured.
In which agar block will the rate of diffusion be fastest and why?
1 because the surface area to volume ratio is smaller
1 because the surface area to volume ratio is bigger
2 because the surface area to volume ratio is bigger
both will be the same as the surface area to volume ratio is equal
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Radish discs were placed in a solution containing Na+ ions.
The concentration of O2 in the air bubbled through the solution was changed and the rate of Na+ uptake measured. The results are shown.
| Concentration of oxygen / % | Rate of Na+ uptake / arbitrary units |
| 3.10 | 31 |
| 12.6 | 64 |
| 19.8 | 83 |
Which process is responsible for the uptake of Na+ in this experiment?
simple diffusion
facilitated diffusion
osmosis
active transport
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The diagram shows a glass cylinder within which a partially permeable membrane separates two compartments, G and H, of the same volume (V).
Each compartment contains saline solution, the concentration (C) in G is double the concentration in H.
The membrane is attached to a sliding piston.
Which equations correctly describe the concentration and volume of compartments when osmotic equilibrium is reached?
CG = 2CH and VG = 2VH
CG = CH and VG = VH
CG = 2CH and VG = VH
CG = CH and VG = 2VH
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Four solutions are made, each containing 15 g l-1 of a molecule. Which molecule would produce the solution with the lowest water potential?
starch
DNA
glucose
insulin
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The graph shows how the concentration of a substance affects its rate of absorption into a cell.
Substance X enters by simple diffusion, substance Y by facilitated diffusion.
Why does the curve for substance Y plateau above a certain concentration?
ATP production rate reaches a maximum level
The concentration of Y reaches equilibrium on each side of the membrane
Carrier proteins are saturated
The membrane because impermeable to Y at a certain concentration
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The cell walls of three plant cells, X, Y and Z, are in contact with each other. The water potentials inside each cell are shown in the table
| Cell | Water potential (kPa) |
|
X Y Z |
-900 -300 -600 |
How will water move by osmosis between the cells?
Z to X Y to Z X to Y
Y to X Z to Y X to Z
X to Z Y to Z Z to Z
Y to Z Y to X Z to X
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