Water Potential quiz #2 Flashcards
Water Potential quiz #2
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Which of the following plant cells would exhibit the most turgor pressure: a wilted plant cell, a flaccid plant cell, or a healthy plant cell?
A healthy plant cell would exhibit the most turgor pressure because its vacuole is full, causing the cell contents to push against the cell wall. Turgor pressure in plant cells is created by the force of the cytoplasm pushing against what structure?
Turgor pressure is created by the cytoplasm pushing against the cell wall. What drives the flow of water through the xylem in plants?
The flow of water through the xylem is driven by the cohesion-tension theory, where evaporation creates negative pressure that pulls water upward. Which of the following processes help a plant conserve water: transpiration, photosynthesis, or closing stomata?
Closing stomata helps a plant conserve water by reducing transpiration. Water potential is generally most negative in which of the following parts of a plant: roots, leaves, or stem?
Water potential is generally most negative in the leaves due to evaporation and transpiration. Which structure or compartment is part of the symplast in plant cells?
The symplast includes the cytosol of plant cells connected by plasmodesmata. Which describes the cells of a wilted plant: turgid, flaccid, or plasmolyzed?
The cells of a wilted plant are flaccid due to loss of turgor pressure. What is the main water source for land plants?
The main water source for land plants is soil, from which water is absorbed through the roots. If a plant is losing too much water through evaporation, what mechanism can it use to reduce water loss?
A plant can close its stomata to reduce water loss through evaporation. What is the role of the Casparian strip in plant roots?
The Casparian strip blocks the apoplastic route, forcing water into endodermal cells to regulate ion flow and solute concentration. What is water potential in plants, and how do solute potential and pressure potential contribute to it?
Water potential (ψ) is the potential energy of water to move between environments. It is determined by solute potential (ψs), which is negative and decreases as solute concentration increases, and pressure potential (ψp), which can be positive or negative. Water moves from areas of high water potential to low water potential. What role does the Casparian strip play in water and ion transport in plant roots?
The Casparian strip is a waxy barrier in the endodermis that blocks the apoplastic route, forcing water and dissolved ions to enter endodermal cells via the symplastic or transmembrane routes. This allows the plant to regulate ion flow and solute concentration before water enters the xylem. How do guard cells regulate the opening and closing of stomata, and why is this important for plant water potential?
Guard cells open stomata by accumulating potassium ions, causing water to enter and cells to swell. To close stomata, potassium ions exit, water follows, and cells shrink. This regulation balances water loss through transpiration with the need for gas exchange, maintaining plant water potential and health.
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