Biology 5090 · O Level
Diffusion and osmosis
70 practice questions on Diffusion and osmosis, with worked solutions and instant marking.
An enzyme is used to remove the cell wall from a plant cell. What would happen if this cell were then put into distilled water?
May/June 2015
The diagram presents three plant cells, P, Q and R, with arrows indicating the direction in which water moves by osmosis. In which order should the cells be arranged for water potential, from highest to lowest?
May/June 2015
The diagram depicts three plant cells named P, Q and R. The arrows indicate the direction in which water moves by osmosis. What is the correct sequence of water potential in the cells, from highest to lowest?
May/June 2015
Describe how active transport takes place.
May/June 2015
Which processes are able to happen only across a membrane?
May/June 2016
Which processes can take place only via a membrane?
May/June 2016
An area of grassland is covered by sea-water. Sea-water has a very high salt concentration. What effect does the sea-water have on the functions of the root hairs?
May/June 2017
Which of the following processes will always take place down a concentration gradient?
May/June 2017
A student prepares four potato cylinders. Each cylinder is $30\,\text{mm}$ in length. The cylinders all have the same diameter. The potato cylinders are then put into sugar solutions with different concentrations. After one hour, the lengths of the cylinders are measured again. The results are shown in the table. Which sugar solution has a water potential nearest to that of the potato cells?
May/June 2017
Which of these statements about diffusion are correct?
May/June 2017
The paragraph below explains how water is absorbed by roots. Root hair cells have ......1...... cell walls, which help them take in water. The cytoplasm in the cell has a ......2...... water potential than the soil water, so water enters the root hair cell from the soil by ......3...... . Which words correctly fill spaces 1, 2 and 3?
May/June 2018
The diagram shows a plant cell after it has been placed in a solution for an hour. What explains the appearance of this cell?
May/June 2019
Which process happens only through diffusion?
May/June 2019
The diagram shows a group of cells in the root of a plant that is taking up water from the soil. In what way is the water potential of the cell labelled 2 different from the water potentials of the cells labelled 1 and 3?
May/June 2019
Define osmosis and explain why it counts as a distinctive form of diffusion.
May/June 2019
A sample of plant tissue is moved from a beaker containing water into a concentrated sugar solution. Which row shows what happens?
May/June 2021
The diagram illustrates two onion plants. From the information shown in the diagram, which statement about these onion plants is correct?
May/June 2021
By what process does water enter root hair cells?
May/June 2021
A piece of plant tissue is moved from a beaker containing water into a concentrated sugar solution. Which row shows what happens?
May/June 2021
The diagrams illustrate four different plant cells. Each one is performing aerobic respiration. Which diagram shows the movement of carbon dioxide molecules?
May/June 2022
The diagram is of a cell. Which cell process is illustrated by the movement of substances shown in the diagram?
May/June 2022
What does diffusion mean?
May/June 2022
The experiment illustrated was assembled and then left for 30 minutes. The membrane allows sugar and water through but does not allow starch or protein through. After 30 minutes, samples of the water in the beaker were tested using Benedict’s reagent, biuret reagent and iodine solution. What colours would be produced in these tests?
May/June 2022
The diagram presents a cross-section through a human molar tooth.
May/June 2022
Which statement is correct in all cases for both diffusion and osmosis?
May/June 2023
Which of the following statements about diffusion are correct?
May/June 2023
Several ways that molecules can travel into and out of cells are given. 1 Molecules move from a region of higher concentration to a region of lower concentration. 2 Molecules move from a region of lower concentration to a region of higher concentration. 3 Molecules move from a region of higher concentration to a region of lower concentration through a partially permeable membrane. Which statement is the correct one?
May/June 2023
A group of students investigated water movement by osmosis using potato tissue. They were given: • a balance • five cylinders of potato tissue with equal diameters • five different concentrations of sodium chloride (salt) solution at room temperature • five test-tubes • a sharp knife • a white tile • a marker pen / pencil • paper towels. They carried out the method below: • label the test-tubes 0%, 2%, 4%, 6% and 8% • cut each potato cylinder so that each one has a mass of $3.0\,\text{g}$ • put one potato cylinder into each test-tube • add the corresponding salt solution to each test-tube so that the potato cylinder inside is covered, as shown in Fig. 1.1 • note the time and leave the potato cylinders in the solutions for 40 minutes • after 40 minutes remove the potato cylinders from the test-tubes • dry each potato cylinder with a paper towel • measure and record the mass of each potato cylinder.
May/June 2023
If animal cells and plant cells are put into distilled water, the animal cells burst whereas the plant cells do not. Which statement accounts for this difference?
May/June 2024
An enzyme is used to remove the cell wall from a plant cell. What would occur if this cell were then put into distilled water?
May/June 2024
Frogs are amphibians, so their skin is partially permeable. They live in and close to water, for example lakes and marshes, where the water has a low concentration of mineral ions. Any water they require is taken in through their skin. Biologists worry that frogs living near coastlines could become endangered if global warming causes sea level to rise. Sea water has a high concentration of mineral ions. What would happen to the frogs if their habitat were flooded with sea water?
May/June 2025
Which combination of factors will cause diffusion to occur at the greatest rate through a membrane?
May/June 2025
A leaf from pondweed ($Elodea$) is mounted on a microscope slide. Sodium chloride solution is then added as a drop. The leaf cells are observed using a light microscope. Which statement describes the cells seen through the microscope?
May/June 2025
Which term refers to the diffusion of molecules?
Oct/Nov 2015
The diagram illustrates the net movement of water by osmosis between four neighbouring cells. Which cell has the greatest water potential?
Oct/Nov 2015
Fig. 1.1 presents a plant cell before it is placed in a concentrated salt solution and again after it has been placed in one.
Oct/Nov 2015
Which row gives the description of diffusion into a cell?
Oct/Nov 2016
The diagram shows equipment set up to study osmosis. Which molecules will pass through the partially permeable membrane, and what change will happen to the solution level?
Oct/Nov 2016
The diagram shows apparatus set up to investigate osmosis. Which molecules will pass through the partially permeable membrane, and what change will happen to the solution level?
Oct/Nov 2016
The diagram indicates the direction in which water moves from one cell to another in a plant root. Which cell has the greater water potential, and in what direction does the water move?
Oct/Nov 2017
A student uses a potato and slices out three pieces from it. Each piece measures $5\,\text{cm} \times 0.5\,\text{cm} \times 0.5\,\text{cm}$. He then puts the three potato pieces into three separate sugar solutions. After two hours, he takes the potato pieces out of the sugar solutions and measures their lengths. The results are given in the table. Solution X: $5.2\,\text{cm}$ Solution Y: $4.7\,\text{cm}$ Solution Z: $5.3\,\text{cm}$ What conclusion can be drawn from these results?
Oct/Nov 2017
Which process does not need energy released during respiration?
Oct/Nov 2018
Which of these statements about osmosis are correct?
Oct/Nov 2018
Which of the following statements about diffusion are correct?
Oct/Nov 2018
The diagram illustrates a root hair cell together with the surrounding soil particles. Osmosis takes place when areas of higher and lower water molecule concentration are separated by a partially permeable membrane. On the diagram, what are these areas?
Oct/Nov 2018
Fig. 1 illustrates cells from a plant tissue that were placed on a slide in distilled water and examined with a microscope. Fig. 2 illustrates cells from the same plant tissue after they had been placed on a slide in concentrated salt solution.
Oct/Nov 2018
Which statement is true in every case for both diffusion and osmosis?
Oct/Nov 2019
Which process does not use the energy that respiration releases?
Oct/Nov 2019
Discs of uncooked potato tissue are first weighed to find their initial mass. They are then left in sucrose solutions with different concentrations. After 1 hour, they are weighed again to obtain their final mass. The graph shows how the ratio of initial mass to final mass varies with sucrose solution concentration. Which concentration of sucrose solution has the same water potential as the cells in the potato discs?
Oct/Nov 2019
In dialysis, substances including glucose, mineral salts, urea and water pass between the patient’s blood and the dialysis fluid. Which processes cause these movements?
Oct/Nov 2020
The diagram presents three plant cells, P, Q and R. The arrows indicate the direction in which water moves by osmosis. What is the correct sequence of water potential in the cells, from highest to lowest?
Oct/Nov 2020
Which of the following statements about diffusion are correct?
Oct/Nov 2020
State the substance that plants absorb by means of osmosis.
Oct/Nov 2020
Many processes in the body need energy. Which process is carried out without using energy?
Oct/Nov 2021
Which process takes place by diffusion only?
Oct/Nov 2021
What biological process is shown in the diagram?
Oct/Nov 2021
An experiment designed to investigate osmosis is arranged as shown. What happens to the level of the liquid in tube X and the concentration of the salt solution?
Oct/Nov 2021
Which one of the following statements about diffusion is correct?
Oct/Nov 2021
An experiment arranged as shown is used to study osmosis. What changes occur to the level of the liquid in tube X and to the concentration of the salt solution?
Oct/Nov 2021
The diagram illustrates an experiment. After $30$ minutes, tests were done on the contents of the membrane bag and on the water in the beaker. Which row gives the test results?
Oct/Nov 2022
The diagram illustrates the transfer of substances between blood in a capillary and tissue fluid. Through which process does water move from tissue fluid into the capillary?
Oct/Nov 2022
A diagram of a typical plant cell is shown after it has remained in a concentrated salt solution for 10 minutes. Which numbered structures are partially permeable?
Oct/Nov 2022
The diagram represents a typical plant cell that has been placed in a concentrated salt solution for $10$ minutes. Which numbered structures are partially permeable?
Oct/Nov 2022
The diagram presents two plant cells, X and Y. Cell X has a greater water potential than Y. In what direction, and through which process, will water move between these two cells?
Oct/Nov 2023
The bacterium Vibrio cholerae, which causes the disease cholera, acts on cells in the intestinal wall. It makes chloride ions move from the cells into the small intestine. Which process will then cause dangerously large amounts of watery diarrhoea to be produced?
Oct/Nov 2024
The diagram indicates the water potentials, given in units of $\text{kPa}$, for a group of plant cells. A more negative value means a lower water potential. Which sequence of arrows represents the net movement of water from cell X?
Oct/Nov 2024
Contact lenses are worn on the surface of the eye to correct vision defects. One kind of contact lens is partially permeable and is usually kept in a sterile sodium chloride solution. The sodium chloride solution has the same concentration as the fluid covering the surface of the eye. A person accidentally stores their contact lenses in distilled water instead of sodium chloride solution. They then put a contact lens onto the surface of their eye. Which pair of statements describes what happens next?
Oct/Nov 2025
Which of the following statements about osmosis is correct?
Oct/Nov 2025
Oxygen is formed in leaf cells during photosynthesis and diffuses out from the leaf. Through which route does the oxygen diffuse?
Oct/Nov 2025
Fig. 3.1 is a photomicrograph showing cells from a plant epidermis after treatment so that some of the cells are plasmolysed. Fig. 3.1 labels: cytoplasm in non-plasmolysed cell X; cytoplasm in plasmolysed cell Y; cell wall of plasmolysed cell Y; magnification \times150.
Oct/Nov 2025