Which row correctly labels this diagram of a cell surface membrane?
 | Cholesterol | Glycoprotein | Glycolipid | Protein | Phospholipid |
A. | 3 | 2 | 4 | 1 | 5 |
B. | 5 | 3 | 2 | 4 | 1 |
C. | 1 | 4 | 2 | 3 | 5 |
D. | 5 | 2 | 4 | 3 | 1 |
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Syllabus Edition
First teaching 2014
Last exams 2024
Which row correctly labels this diagram of a cell surface membrane?
 | Cholesterol | Glycoprotein | Glycolipid | Protein | Phospholipid |
A. | 3 | 2 | 4 | 1 | 5 |
B. | 5 | 3 | 2 | 4 | 1 |
C. | 1 | 4 | 2 | 3 | 5 |
D. | 5 | 2 | 4 | 3 | 1 |
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What is the main function of cholesterol in the cell surface membrane?
To provide hydrophilic channels.
To regulate membrane fluidity.
To assist active transport.
To assist cell adhesion.
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Which of the following correctly describes the model of membrane structure that is now widely accepted?
A phospholipid bilayer with a series of proteins that are free to move around within the membrane.
A phospholipid bilayer.
A phospholipid bilayer with a layer of protein on either side.
A phospholipid bilayer with a series of proteins in fixed positions throughout.
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Which of the statements about membrane fluidity is correct?
The higher the proportion of unsaturated fatty acid tails in a membrane, the higher the membrane fluidity.
Cholesterol can restrict the motion of the molecules in a membrane, increasing membrane fluidity.
Cells do not need to regulate membrane fluidity.
The lower the proportion of unsaturated fatty acid tails in a membrane, the higher the membrane fluidity.
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Which of the following modes of transport is not an example of active or bulk transport?
Water moving through a partially permeable membrane.
Phagocytosis of a pathogen.
Exocytosis.
Endocytosis.
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The sentence below describes a cellular process and an associated eukaryotic cellular structure.
 Cells which have a high rate of …I… will have many ...II… .
 Select the terms that best fit the gaps in this sentence.
 | I | II |
A | Facilitated diffusion | Mitochondria |
B | DNA replication | Lysosomes |
C | Exocytosis | Vesicles |
D | Phospholipid production | Ribosomes |
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The diagram below shows red blood cells that have been bathed in solutions of different solute concentration.
Which row of the table correctly describes the three solutions that these red blood cells have been bathed in?
 | I | II | III |
A | Same osmolarity (isotonic) |
Higher osmolarity (hypotonic) | Lower osmolarity (hypertonic) |
B | Same osmolarity (isotonic) |
Higher osmolarity (hypertonic) | Lower osmolarity (hypotonic) |
C | Same osmolarity (isotonic) |
Lower osmolarity (hypotonic) | Higher osmolarity (hypertonic) |
D | Higher osmolarity (hypertonic) | Lower osmolarity (hypotonic) | Same osmolarity (isotonic) |
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Which row correctly matches the molecules found in the cell surface membrane with their function?
 | Influences membrane fluidity | Act as receptor sites for hormones | Bind to antibodies |
A | Glycolipids and glycoproteins | Cholesterol | Proteins and glycolipids |
B | Glycoproteins | Glycolipids and glycoproteins | Cholesterol |
C | Cholesterol | Proteins and glycoproteins | Glycoproteins |
D | Phospholipids and cholesterol | Proteins and glycolipids | Phospholipids and cholesterol |
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Cystic fibrosis causes a defect in the cell surface membrane of epithelial cells, disrupting the transport of chloride ions out of affected cells.
Which membrane component is affected?
CholesterolÂ
Proteins
Glycolipids
PhospholipidsÂ
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A student sketches a section of a cell surface membrane to show the fluid mosaic model.
How would they correctly label their sketch?
 | W | X | Y | Z |
A | Integral protein | Peripheral protein | Phospholipid | Glycoprotein |
B | Peripheral protein | Integral protein | Glycoprotein | Phospholipid |
C | Glycoprotein | Peripheral protein | Integral protein | Phospholipid |
D | Integral protein | Integral protein | Glycoprotein | Phospholipid |
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Select the table row that correctly completes the following sentence:
Cholesterol is a component of animal cell membranes. Most of a cholesterol molecule is ...I… . This means that cholesterol ...II…Â
 | I | II |
A | ...hydrophobic, so it is attracted to the hydrocarbon tails at the centre of the membrane. | ...reduces the fluidity of the membrane and reduces its permeability to particles such as sodium ions and hydrogen ions. |
B | ...hydrophilic, so it is attracted to the hydrocarbon tails at the centre of the membrane. | ...increases the fluidity of the membrane and reduces its permeability to particles such as sodium ions and hydrogen ions. |
C | ...hydrophobic, so it is attracted to the hydrocarbon tails at the centre of the membrane. | ...reduces the fluidity of the membrane and increases its permeability to particles such as sodium ions and hydrogen ions |
D | ...hydrophilic, so it is attracted to the phosphate heads on the periphery of the membrane. | ...increases the fluidity of the membrane and increases its permeability to particles such as sodium ions and hydrogen ions. |
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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 and 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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Halophytes are plants that are able to survive in regions where they are regularly covered by salty seawater.Â
Which adaptation would you expect halophytes to have to enable them to live in this environment?
Root hair cells with a low osmolarity.
Cells with a high number of chloroplasts.
Root hair cells which accumulate salts and other solutes.
Cells with a low number of mitochondria.
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The Davson-Danielli model of cell membrane structure stated that cell membranes consisted of a phospholipid bilayer sandwiched between two layers of protein.
Which piece of evidence contributed to the falsification of the Davson-Danielli model and the acceptance of the Singer-Nicolson fluid mosaic model?
The presence and positioning of globular peripheral and integral proteins.
The amphipathic properties of phospholipids.
The presence of a hydrophobic region on the surface of the membrane.
The orientation of the hydrophobic phospholipid tails away from the proteins.
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What is the difference between simple diffusion and facilitated diffusion?
 | Simple diffusion | Facilitated diffusion |
A | Diffusion rate inversely proportional to concentration gradient | Diffusion rate proportional to concentration gradient |
B | Never involves a membrane | Always involves a membrane |
C | Occurs across any part of the membrane | Occurs via channels in the membrane |
D | A passive process that does not require energy from ATP | An active process that requires energy from ATP |
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Signalling molecules are used to transfer information around the body. Once at the target cell, there are different ways in which different types of signalling molecule cause a response.
Which of the following is able to enter a cell directly through the phospholipid bilayer to cause a response without the requirement for a membrane protein?
lipid-based hormones
protein-based hormones
neurotransmitters
charged molecules
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Proteins in the cell surface membranes of mouse cells and human cells were labelled with coloured dyes, with a different colour for human and mouse proteins.
When a cell from each species is fused together, the different-coloured labels are first found in different regions of the hybrid cell’s cell surface membrane. After 40 minutes, the labels are evenly distributed around the entire cell surface membrane. This is shown in the diagram below; the viewpoint is looking down onto the surface of the membrane.
 What explains this observation?
Groups of protein and phospholipid molecules in the cell surface membrane are attached to each other and move together.
Only protein molecules in the outer layer of the cell surface membrane can move freely between phospholipid molecules.
All protein molecules in the cell surface membrane are fixed to structures within the cell, but phospholipid molecules move freely between them.
Protein molecules in the outer layer of the cell surface membrane and those which span the bilayer can move freely between phospholipid molecules.
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Membranes in cells include the following components.
Which row of the table shows the correct function of each component?Â
 |
Stabilising the hydrophobic layer |
Recognising self / non self |
Being not fully permeable to water |
Transporting ions through membranes |
A. |
1 |
2 |
3 |
4 |
B. |
3 |
1 |
2 |
4 |
C. |
1 |
3 |
1 |
2 |
D. |
4 |
3 |
4 |
2 |
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An experiment to calculate the osmolarity of potato was performed using the following protocol:
The mean mass of the potato cubes was 2.50g before being added to the solution and the graph shows the masses of potato cubes after the experiment.
What concentration of sucrose has the same osmolarity as the potato?
0.00 mol dm-3
0.12 mol dm-3
0.31 mol dm-3
0.66 mol dm-3
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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.Â
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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