Water Potential in Plants
40 Questions
2 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What causes water to move into the plant cell osmotically?

  • Higher osmotic potential of the solution compared to the cell
  • Higher solute concentration in the cytosol than in the solution (correct)
  • Higher pressure in the cytosol compared to the solution
  • Lower solute concentration in the cytosol than in the solution

    • What is a consequence of ΨSsoln being greater than ΨScell?

  • Water leaves the cell
  • The cell becomes plasmolyzed
  • Water enters the cell
  • The pressure potential of the cell increases (correct)

    • Which of the following is not a factor contributing to the turgor pressure of a plant cell?

  • Presence of a rigid cell wall
  • Presence of a selectively permeable plasma membrane
  • Presence of high atmospheric pressure (correct)
  • High solute concentration in the cytosol

    • What condition results in no net water movement in a plant cell?

    <p>ΨSsoln = Ψcell</p> Signup and view all the answers

    Which statement about turgor pressure is true?

    <p>Turgor pressure is due to the outward pressure of the cell wall</p> Signup and view all the answers

    Which of the following states the relationship between ΨScell and ΨSsoln correctly?

    <p>ΨScell is less negative than ΨSsoln</p> Signup and view all the answers

    What happens to a plant cell when its ΨPcell is less than ΨPsoln?

    <p>The cell may become plasmolyzed</p> Signup and view all the answers

    When a plant cell reaches equilibrium with its surrounding solution, what is true about its water potential?

    <p>Ψcell equals Ψsoln</p> Signup and view all the answers

    What role does the extensibility of the cell wall play in a less idealized cell?

    <p>It allows for significant volume changes.</p> Signup and view all the answers

    What effect does placing a less idealized cell in a solution with lower solute concentration than its cytosol have on the cell?

    <p>Water moves into the cell, diluting its solute content.</p> Signup and view all the answers

    What condition leads to plasmolysis in a less idealized cell?

    <p>Lower solute concentration inside the cell than outside.</p> Signup and view all the answers

    When a less idealized cell's solute potential (ΨS) is greater than that outside the cell, what happens?

    <p>Water exits the cell, and solute concentration increases inside.</p> Signup and view all the answers

    What is the primary characteristic of a plasma membrane (PM) in a less idealized cell?

    <p>It is selectively permeable to water but not to solutes.</p> Signup and view all the answers

    How does the selective permeability of the less idealized cell's PM affect water movement?

    <p>Water moves freely, but solutes cannot.</p> Signup and view all the answers

    What occurs when the cell's turgor pressure (ΨPcell) increases?

    <p>The cell becomes more rigid and swollen.</p> Signup and view all the answers

    What happens to the cellular solute content when a less idealized cell is placed in a hypertonic solution?

    <p>The solute content becomes concentrated.</p> Signup and view all the answers

    What happens to a plant cell when it is placed in a solution with higher osmotic strength?

    <p>Plasmolysis occurs as the cell loses water.</p> Signup and view all the answers

    What is the turgor pressure of a flaccid cell?

    <p>0 MPa</p> Signup and view all the answers

    How does adding mannitol to a beaker of pure water affect osmotic potential?

    <p>It increases the solute concentration and decreases osmotic potential.</p> Signup and view all the answers

    What is the relationship between solute potential (ΨS) and pressure potential (ΨP) in plasmolysis?

    <p>Pressure potential is equal to zero during plasmolysis.</p> Signup and view all the answers

    What happens to the concentration of solutes in the cell during plasmolysis?

    <p>It equals that of the bathing solution.</p> Signup and view all the answers

    Which of the following statements correctly describes turgid cells?

    <p>Turgid cells have a turgor pressure of about 0.5 MPa.</p> Signup and view all the answers

    What could be inferred about a solution with a lot of mannitol added to it?

    <p>It contains a high concentration of solutes.</p> Signup and view all the answers

    What does ΨP represent in the context of plant cells?

    <p>Turgor pressure inside the cell.</p> Signup and view all the answers

    What does ΨP represent in the equation Ψ = ΨS + ΨP + ΨM?

    <p>Effect of pressure on water potential</p> Signup and view all the answers

    How does increasing pressure affect ΨP?

    <p>It increases the free energy of the system</p> Signup and view all the answers

    At standard atmospheric pressure, what is the value of ΨP?

    <p>0 MPa</p> Signup and view all the answers

    What happens to water movement in response to pressure gradients?

    <p>Water moves from higher ΨP to lower ΨP</p> Signup and view all the answers

    Which of the following statements about ΨP and atmospheric pressure is true?

    <p>ΨP increases above 0 MPa under high atmospheric pressure</p> Signup and view all the answers

    In plant tissues, what maximum value can ΨP reach?

    <p>3 MPa</p> Signup and view all the answers

    When atmospheric pressure is below standard atmospheric pressure, what happens to ΨP?

    <p>ΨP becomes negative</p> Signup and view all the answers

    What is generally assumed regarding atmospheric pressure when calculating plant water relations?

    <p>AP is typically ignored in calculations</p> Signup and view all the answers

    What happens to the protoplasm during plasmolysis?

    <p>It shrinks and pulls away from the cell wall.</p> Signup and view all the answers

    What is the relationship between ΨPcell and ΨSenvironment in a plasmolyzed cell?

    <p>ΨPcell is zero MPa, which equals ΨSenvironment.</p> Signup and view all the answers

    What effect does a concentrated solution have on onion epidermal cells?

    <p>It causes the cells to exhibit plasmolysis.</p> Signup and view all the answers

    During plasmolysis, what remains attached to the cell wall?

    <p>Strands of the plasma membrane.</p> Signup and view all the answers

    Which component largely composes the protoplasm in onion cells?

    <p>Vacuoles.</p> Signup and view all the answers

    What does ΨP represent in the context of plasmolysis?

    <p>Pressure potential inside the cell.</p> Signup and view all the answers

    What is the typical observation when onion epidermal cells undergo turgor pressure?

    <p>Cells exhibit a full and swollen appearance.</p> Signup and view all the answers

    What is the role of anthocyanins in the vacuoles of onion cells?

    <p>They act as pigments for coloration.</p> Signup and view all the answers

    Study Notes

    Water Potential Components

    • Water potential (Ψ) is the sum of pressure potential (ΨP), solute potential (ΨS), and matric potential (ΨM): Ψ = ΨS + ΨP + ΨM.
    • Pressure potential (ΨP) is the effect of pressure on water potential and is not affected by solute concentration. Increasing pressure increases the free energy of the system.
    • Water moves from areas of higher pressure potential to lower pressure potential across a selectively permeable membrane.
    • Standard atmospheric pressure (SAP) defines ΨP = 0 MPa (1 atm = 0.1013 MPa). ΨP > 0 MPa if atmospheric pressure (AP) exceeds SAP; ΨP < 0 MPa if AP is below SAP. Generally, ΨP = AP – SAP.
    • In plant water relations calculations, slight deviations from SAP are often ignored, assuming AP = SAP = 0.1013 MPa. Plant tissues can have ΨP values up to 3 MPa.

    Plant Cell Turgor

    • Plant cell turgor results from a higher solute concentration in the cytosol compared to the outside, a selectively permeable plasma membrane (PM), and a cell wall preventing rupture.
    • A high cellular solute concentration and cell wall lead to positive pressure potential (ΨPcell > 0).

    Less Idealized Plant Cell

    • A less idealized plant cell has a somewhat extensible cell wall, allowing volume changes.
    • If placed in a solution with lower solute concentration than the cytosol, water moves into the cell osmotically, diluting the cellular solute content and increasing ΨPcell.
    • If placed in a solution with higher solute concentration, water moves out osmotically, concentrating the cellular solute content and decreasing ΨPcell.

    Plasmolysis

    • Plasmolysis occurs when ΨScell > ΨS of the surrounding solution (i.e., solute concentration in the cell is lower than in the environment).
    • During plasmolysis, the PM pulls away from the cell wall, and the protoplasm shrinks. ΨPcell becomes 0 MPa, and ΨScell equals the solute potential of the environment.

    Red Onion Epidermal Peels and Plasmolysis

    • Red onion epidermal peels are useful for visualizing plasmolysis due to the presence of anthocyanins (red pigments).
    • In dilute solutions, cells are turgid (ΨP > 0 MPa). In concentrated solutions, protoplasm shrinks and pulls away from the cell wall, showing loss of turgor (ΨP = 0 MPa).

    Turgid vs. Flaccid Cells

    • A turgid leaf cell has a positive pressure potential (e.g., ~0.5 MPa), while a flaccid cell has zero turgor (ΨPcell = 0 MPa).
    • Cells in plasmolysis have the same ΨP (0 MPa) but different ΨS, with plasmolyzed cells having a lower (more negative) ΨS.

    Thought Experiment: Mannitol Addition

    • Initially, in a beaker of pure water, Ψ = 0, ΨS = 0, and ΨP = 0.
    • After adding mannitol, ΨS becomes negative, and ΨP remains unchanged (0 MPa) in an open container, meaning the overall water potential (Ψ) also becomes negative.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Water Potential PDF

    Description

    This quiz covers the key components of water potential, including pressure potential, solute potential, and matric potential. Understand how these factors influence water movement in plant cells and their significance in plant turgor. Test your knowledge on the equations and principles governing these concepts.

    More Like This

    Quiz sobre procesos de difusión
    10 questions

    Quiz sobre procesos de difusión

    PlushAwareness avatar
    PlushAwareness
    Plant Physiology: Water Potential
    20 questions

    Plant Physiology: Water Potential

    RichStarlitSky avatar
    RichStarlitSky
    Water Potential in Plants
    6 questions

    Water Potential in Plants

    BrotherlySymbol avatar
    BrotherlySymbol
    Potenziale Idrico nelle Piante
    39 questions

    Potenziale Idrico nelle Piante

    ReceptiveNovaculite7120 avatar
    ReceptiveNovaculite7120
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser