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What is the primary function of xylem in plants?
What is the primary function of xylem in plants?
Xylem cells are living cells that contain cell contents.
Xylem cells are living cells that contain cell contents.
False
What adaptation do xylem cells have that allows them to support plants?
What adaptation do xylem cells have that allows them to support plants?
Thickened outer walls with lignin
Root hair cells absorb water and minerals from the soil through ______.
Root hair cells absorb water and minerals from the soil through ______.
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Match the following functions with their corresponding structures:
Match the following functions with their corresponding structures:
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What is the significance of root hairs in plants?
What is the significance of root hairs in plants?
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The process of mineral ion absorption by root hair cells occurs through osmosis.
The process of mineral ion absorption by root hair cells occurs through osmosis.
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What drives water entry into root hair cells?
What drives water entry into root hair cells?
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What process causes water to pass into root hair cells?
What process causes water to pass into root hair cells?
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Water moves through root cortex cells before entering the xylem.
Water moves through root cortex cells before entering the xylem.
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What is the name of the vessels that carry water up to the leaves in plants?
What is the name of the vessels that carry water up to the leaves in plants?
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The pathway of water is: root hair cell → root cortex cells → ______ → leaf mesophyll cells.
The pathway of water is: root hair cell → root cortex cells → ______ → leaf mesophyll cells.
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Match the following components with their roles:
Match the following components with their roles:
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What can be used to investigate water movement in plants?
What can be used to investigate water movement in plants?
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A cross-section of the celery shows that all areas of the stalk are stained when dyed water is used.
A cross-section of the celery shows that all areas of the stalk are stained when dyed water is used.
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What happens to the leaves of a celery plant in dyed water after a few hours?
What happens to the leaves of a celery plant in dyed water after a few hours?
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Which of the following factors affects the rate of transpiration?
Which of the following factors affects the rate of transpiration?
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High humidity decreases the rate of transpiration.
High humidity decreases the rate of transpiration.
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What happens to a plant when it wilts?
What happens to a plant when it wilts?
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When a plant wilts, it is because __________ water evaporates from its leaves than is available in the soil.
When a plant wilts, it is because __________ water evaporates from its leaves than is available in the soil.
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Match the factors affecting transpiration with their effects:
Match the factors affecting transpiration with their effects:
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What is the purpose of using heat in the process described?
What is the purpose of using heat in the process described?
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Dry leaves will affect the transpiration rate results.
Dry leaves will affect the transpiration rate results.
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What should be done to the air bubble before recording the end location?
What should be done to the air bubble before recording the end location?
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Transpiration occurs faster when the ______ increases.
Transpiration occurs faster when the ______ increases.
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Match the following environmental factors with their effect on transpiration:
Match the following environmental factors with their effect on transpiration:
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What is the first step in setting up the experiment for measuring transpiration?
What is the first step in setting up the experiment for measuring transpiration?
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Changing multiple environmental factors at once is recommended during the experiment.
Changing multiple environmental factors at once is recommended during the experiment.
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What should you do after allowing the plant to adapt to a new environment?
What should you do after allowing the plant to adapt to a new environment?
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What happens to the rate of transpiration as temperature increases?
What happens to the rate of transpiration as temperature increases?
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Wind speed has no effect on the rate of transpiration.
Wind speed has no effect on the rate of transpiration.
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What creates a continuous column of water in the transpiration stream?
What creates a continuous column of water in the transpiration stream?
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Transpiration produces a tension or ‘pull’ on the water in the xylem vessels that is created by the _____ of the leaves.
Transpiration produces a tension or ‘pull’ on the water in the xylem vessels that is created by the _____ of the leaves.
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What role do stomata play in transpiration?
What role do stomata play in transpiration?
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The many interconnecting air spaces between mesophyll cells help to create a large surface area for evaporation.
The many interconnecting air spaces between mesophyll cells help to create a large surface area for evaporation.
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What is the primary pathway for water movement from roots to leaves in a plant?
What is the primary pathway for water movement from roots to leaves in a plant?
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What is the main substance transported by phloem?
What is the main substance transported by phloem?
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Phloem vessels are made of dead cells.
Phloem vessels are made of dead cells.
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What is the process called when sucrose and amino acids are moved through the phloem?
What is the process called when sucrose and amino acids are moved through the phloem?
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During winter, the phloem may transport dissolved sucrose and amino acids from the __________ to other parts of the plant.
During winter, the phloem may transport dissolved sucrose and amino acids from the __________ to other parts of the plant.
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Match the following terms with their definitions:
Match the following terms with their definitions:
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Which part of the plant typically becomes the source during the summer?
Which part of the plant typically becomes the source during the summer?
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Phloem transport only occurs in one direction.
Phloem transport only occurs in one direction.
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Name the two main substances that are primarily transported through the phloem.
Name the two main substances that are primarily transported through the phloem.
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Study Notes
Transport in Plants
- Xylem and Phloem: Plants contain two types of transport vessels: xylem and phloem.
- Xylem Vessels: Transport water and minerals from the roots to the stem and leaves.
- Phloem Vessels: Transport food materials (primarily sucrose and amino acids) made during photosynthesis from leaves to non-photosynthesizing parts of the plant. These are in vascular bundles throughout the plant.
- Vascular Bundles: These bundles group the xylem and phloem together, which are arranged throughout the root, stem and leaves.
Xylem Function
- Function: Transport tissue for water and dissolved mineral ions.
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Adaptations:
- Cells are joined end-to-end, with no cross walls, forming a long continuous tube.
- The cells are essentially dead, without contents, allowing for efficient water transport.
- Outer walls are thickened with lignin, providing strength and support to the plant.
Root Hair Cells
- Structure: Extensions of epidermal cells in the root. Increase the surface area for absorption.
- Function: Absorption of water and mineral ions from the soil primarily by osmosis. Active transport also plays a role.
Pathway Taken by Water
- Process: Water moves from the soil, through the root hair cells, through the cortex cells, to the xylem vessels, and then to the leaves. This movement is primarily driven by osmosis.
- Pathway: root hair cell → root cortex cells → xylem → leaf mesophyll cells
Investigating Water Movement
- Method: A plant (like celery) is placed in a dyed water solution.
- Observation: After a few hours, the leaves and stem will take on the color of the dye. This shows the pathway of water transport, indicating that xylem vessels transport the water through the plant. Specific dissection of celery cross-sections using a scalpel will easily isolate the xylem vessels.
Transpiration
- Definition: Evaporation of water from plant leaves, followed by diffusion of water vapor through the stomata, which are typically on the underside of plant leaves to reduce water loss.
- Xylem Adaptation: Xylem vessels are adapted in structure that facilitates upward movement of water against gravity. The hollow structure, lack of cell contents and reinforcing lignin support the column of water. Lignin reinforces walls to keep them stable and hollow for efficient water movement.
- Mechanism: Cohesion and adhesion give water molecules the tendency to stick together and resist downward movement. Transpiration creates a tension, or pull, on water in the xylem, drawing water up the plant.
Explaining the effects of temperature, wind speed, and humidity
- Temperature: Higher temperatures lead to faster transpiration rates due to increased evaporation.
- Wind Speed: Higher wind speeds increase transpiration because they remove water vapor from around the leaf, increasing the concentration gradient for water loss.
- Humidity: Higher humidity decreases transpiration because the air is already saturated with water vapor, lowering the concentration gradient.
Transpiration Stream (Extended)
- Mechanism: Water molecules are drawn up the xylem by the transpiration pull. The cohesion of water molecules and adhesion of water (to the xylem cell walls) is crucial in this process, creating a continuous column against gravity.
Translocation (Extended)
- Substance Transported (Sugars): Sugars (mainly sucrose) and amino acids manufactured during photosynthesis are carried around the plant in phloem. This movement is called translocation.
- Direction: The direction can change in different stages of the plant's life cycle. It is generally from the source (where glucose is produced), to the sink (where it is stored or used).
- Xylem vs Phloem: Xylem moves water in one direction, whereas translocation can work in all directions in the phloem.
Wilting
- Cause: If water loss from leaves exceeds water uptake by the roots, the plant wilts due to reduced turgor pressure in the cells.
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Description
This quiz explores the functions and adaptations of xylem and root hair cells in plants. It covers water and mineral absorption processes, as well as the significance of these structures in supporting plant life. Test your knowledge on how water moves through various plant parts!
