osmosis flashcards

All 20 cards

1. Card 1

   Define diffusion and provide an example of this process in biological systems.

   Diffusion is the movement of molecules from areas of high concentration to areas of lower concentration. An example is the diffusion of oxygen into cells and carbon dioxide out of cells.

2. Card 2

   How are cell membranes selectively permeable, and what role do proteins play in this characteristic?

   Cell membranes are selectively permeable because they allow some, but not all, materials to pass through. Proteins embedded in the membrane facilitate the passage of certain chemicals, either by diffusion or active transport, while acting as barriers to others.

3. Card 3

   Define osmosis and provide an example of where it occurs.

   Osmosis is the movement of water from an area of high concentration to an area of lower concentration across a semi-permeable membrane. An example is water moving into an animal cell when it is immersed in pure water.

4. Card 4

   Explain what is meant by the term 'turgid' in the context of plant cells.

   A plant cell is said to be turgid when it has absorbed water, causing the cytoplasm to push against the cell wall. The cell wall prevents the cell from bursting, leading to an increase in internal pressure.

5. Card 5

   Describe how turgidity is used in plants for support.

   Turgor pressure, the force of the cell contents against the cell wall, is crucial for plant structure. When plant cells are turgid, they become firm, providing rigidity and support to the plant, which helps it stand upright.

6. Card 6

   Explain how a high salt or sugar concentration can be used to preserve food.

   High concentrations of salt or sugar preserve food by creating an environment where microorganisms lose water through osmosis. This osmotic dehydration causes the microbial cells to shrivel and die, preventing food spoilage.

7. Card 7

   Describe a simple experiment to demonstrate osmosis.

   An experiment to demonstrate osmosis could involve placing a plant cell (like a potato slice) into solutions of varying salt concentrations. By observing changes in the potato's mass or firmness, one can infer the movement of water due to osmosis.

8. Card 8

   Distinguish between a solute, a solvent, and a solution.

   A solute is a substance that is dissolved, such as salt. A solvent is the liquid that dissolves other substances, with water being the most common. A solution is the mixture formed when a solute dissolves in a solvent, like saltwater.

9. Card 9

   Why is osmosis considered a special form of diffusion?

   Osmosis is considered a special form of diffusion because it involves the movement of molecules (specifically water) from a region of higher concentration to a region of lower concentration. The key distinction is that osmosis occurs across a selectively permeable membrane.

10. Card 10

    What is osmoregulation, and why is it important for organisms like Amoeba?

    Osmoregulation is the control of water and salt levels within a cell or organism. For organisms like Amoeba, which live in freshwater, osmoregulation is vital to prevent excessive water intake by osmosis, often managed by structures like contractile vacuoles.

11. Card 11

    Explain the difference in how animal cells and plant cells respond when placed in a less concentrated solution.

    When placed in a less concentrated solution, water moves into both animal and plant cells by osmosis. Animal cells, lacking a cell wall, will swell and can burst (hemolysis), while plant cells become turgid due to their rigid cell wall preventing bursting.

12. Card 12

    What happens to a plant cell when it is placed in a highly concentrated solution, and what is this process called?

    When a plant cell is placed in a highly concentrated solution, it loses water by osmosis. This causes the cell membrane to shrink and pull away from the cell wall, a process known as plasmolysis.

13. Card 13

    How does active transport differ from diffusion in terms of energy requirement and concentration gradient?

    Active transport differs from diffusion because it requires energy and moves chemicals against the diffusion gradient (from an area of lower concentration to higher concentration). Diffusion, conversely, is a passive process that does not require energy and moves substances down the concentration gradient.

14. Card 14

    Why do animal cells burst when immersed in pure water, but plant cells do not?

    Animal cells burst in pure water because they lack a rigid cell wall, allowing excessive water intake to build up pressure until the cell membrane ruptures. Plant cells, however, possess a strong cell wall that resists the internal pressure, preventing them from bursting and instead becoming turgid.

15. Card 15

    What is the function of the kidneys in relation to osmosis and diffusion?

    The kidneys play a crucial role in osmoregulation by helping to regulate salt and water levels in the blood. This involves processes of both osmosis and diffusion to maintain the body's internal fluid balance.

16. Card 16

    Provide an example of a chemical that is transported into a cell via active transport.

    An example of a chemical transported into a cell via active transport is glucose. Cells often need to take in glucose even when its concentration is already high inside the cell, requiring energy to move it against the concentration gradient.

17. Card 17

    What is the significance of the cell wall being 'fully permeable' in plant cells?

    The cell wall in plant cells is fully permeable, meaning it allows water and dissolved substances to pass through freely. This characteristic is important because it allows water to reach the selectively permeable cell membrane, where osmosis can then occur, leading to turgor.

18. Card 18

    Explain the relationship between turgor and plasmolysis in plant cells.

    Turgor is the outward pressure of the vacuole and cell membrane pushing against the cell wall when a plant cell is full of water. Plasmolysis is the opposite, occurring when the cell loses water and the cell membrane pulls away from the cell wall.

19. Card 19

    How do micro-organisms contribute to food spoilage, and how does food preservation using salt or sugar counteract this?

    Micro-organisms like bacteria and fungi on food cause spoilage by metabolizing nutrients. Food preservation with high salt or sugar concentrations works by inducing osmosis, drawing water out of these microbes, causing them to shrivel and die, thus preventing their growth and spoilage.

20. Card 20

    What is crenation, and under what conditions does it occur in animal cells?

    Crenation is the process where animal cells lose water due to osmosis and consequently shrink and shrivel. This occurs when animal cells are placed in a more concentrated solution (hypertonic solution), meaning the outside environment has less water than inside the cell.

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