2022-05-15T13:35:02+03:00[Europe/Moscow] en true <p>each stoma is surrounded by </p>, <p>feature of outside facing cell walls of guard cells</p>, <p>feature of adjacent facing cell walls of guard cells</p>, <p>guard cells have bands of</p>, <p>true or false</p><p>guard cells have plasmodesmata</p>, <p>describe the CSM of the guard cells</p>, <p>describe the contents of the cytoplasm</p>, <p>describe the chloroplasts of guard cells</p>, <p>describe the mitochondria of guard cells</p>, <p>when do stomata open</p>, <p>what is required for inward osmosis to happen in the guard cells</p>, <p>mechanism to open stomata (1)</p>, <p>mechanism to open stomata (2)</p>, <p>mechanism to open stomata (3)</p>, <p>what is an electrochemical gradient</p>, <p>mechanism to open stomata (4)</p>, <p>mechanism to open stomata (5)</p>, <p>mechanism to open stomata (6)</p>, <p>what is the function of the cellulose microfibrils</p>, <p>what is the importance of having thick outside facing and thin adjacent cell facing cell walls</p>, <p>mechanism to close stomata (1)</p>, <p>mechanism to close stomata (2)</p>, <p>mechanism to close stomata (3)</p>, <p>mechanism to close stomata (4)</p> flashcards

A2 Guard Cells

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  • each stoma is surrounded by

    two guard cells

  • feature of outside facing cell walls of guard cells

    thick

  • feature of adjacent facing cell walls of guard cells

    thin

  • guard cells have bands of

    cellulose microfibrils

  • true or false

    guard cells have plasmodesmata

    false

  • describe the CSM of the guard cells

    often folded and contains many channel and carrier proteins

  • describe the contents of the cytoplasm

    there is a high density of chloroplasts and mitochondria and several small vacuoles

  • describe the chloroplasts of guard cells

    have thylakoids but with few grana

  • describe the mitochondria of guard cells

    have many cristae

  • when do stomata open

    when they gain water by osmosis and become turgid

  • what is required for inward osmosis to happen in the guard cells

    a decrease in water potential

  • mechanism to open stomata (1)

    in response to light, ATP-powered proton pumps in the guard cell CSM actively transport hydrogen (H+) ions out of the guard cell

  • mechanism to open stomata (2)

    this leaves the inside of the guard cells negatively charged compared to the outside

  • mechanism to open stomata (3)

    causes channel proteins in the guard cell CSM to open allowing potassium (K+) ions to move down the electrochemical gradient and enter the guard cells

  • what is an electrochemical gradient

    the combination of the electrical gradient and concentration gradient

  • mechanism to open stomata (4)

    influx of potassium ions increases the solute concentration inside the guard cells lowering the water potential inside the cells

  • mechanism to open stomata (5)

    water now enters the guard cells by osmosis through aquaporins in the CSM and accumulate in the vacuoles increasing their size

  • mechanism to open stomata (6)

    this increases the turgor pressure of the guard cells causing the stoma to open

  • what is the function of the cellulose microfibrils

    only allow guard cells to increase in length not diameter

  • what is the importance of having thick outside facing and thin adjacent cell facing cell walls

    thin walls bend more easily than thick walls causing the guard cells to become curved, opening the stoma

  • mechanism to close stomata (1)

    after certain environmental stimuli are detected, the proton pumps in the guard cell CSM stop actively transporting H+ ions out of the guard cell

  • mechanism to close stomata (2)

    the potassium ions leave the guard cells

  • mechanism to close stomata (3)

    water potential gradient is now reversed and water leaves the guard cell by osmosis

  • mechanism to close stomata (4)

    this causes the guard cell to become flaccid, closing the stomata