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What is the function of root hairs in plants?
The cell wall of a root hair is selectively permeable.
False
What is the main function of the cell membrane in a root hair?
The cell membrane is selectively permeable, allowing only selected substances to pass through it.
The root system of a plant consists of the main root and _______________________ roots.
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What is the main component of a root hair that allows it to absorb water and nutrients?
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Root hairs are extensions of the nucleus of an epidermal cell.
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The_____________________ of a root hair is rigid and freely permeable.
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Match the following components of a root hair with their descriptions:
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What is the effect of sunlight on the rate of transpiration?
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High humidity increases the rate of transpiration.
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What is the cooling effect of transpiration in plants?
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The rate of transpiration is higher when the temperature is ___________.
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Match the factors with their effects on the rate of transpiration:
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What is the process of water and minerals moving upwards from the roots to the stern called?
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What is the effect of wind on the rate of transpiration?
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Transpiration helps maintain the concentration of sap inside the plant body.
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Osmosis is the process of water moving from an area of high concentration to an area of low concentration.
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What is the role of root-hairs in the ascent of sap?
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Why is transpiration important in plants?
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The central _______________ is responsible for transporting water and minerals upwards from the roots.
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Match the following components with their functions:
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What is the direction of the movement of water and minerals in the ascent of sap?
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The ascent of sap is an active process that requires energy.
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What is one importance of the ascent of sap?
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What are the three main ways water is important for plants?
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During photosynthesis, water combines with oxygen to produce glucose and carbon dioxide.
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What is the cooling effect experienced under a tree on a hot summer day due to?
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Water in xylem and phloem of a plant transports substances in a ______________ form.
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Match the ways water is important for plants with their descriptions:
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What is the purpose of covering a small, well-watered potted plant with a transparent polythene bag in Activity 3?
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What is the primary characteristic of a semi-permeable membrane?
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The concentration of sugar molecules is higher in Side A.
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What is the main difference between Side A and Side B?
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The semi-permeable membrane has pores of a size that allows _______ molecules to pass through.
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Match the following components with their descriptions:
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What is the direction of water molecules in the diagram?
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Sugar molecules can pass through the semi-permeable membrane.
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What is the purpose of the diagram in the figure?
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Study Notes
Root System in Plants
- A plant's root system consists of a main root, lateral roots, and root hairs.
- Root hairs are long extensions of epidermal cells that absorb water and minerals from the soil.
- Root hairs have a rigid cell wall and a selectively permeable cell membrane that allows water and minerals to pass through.
Structure of a Root Hair
- A root hair cell consists of a cell wall, cell membrane, cytoplasm, and nucleus.
- The cell wall is rigid and freely permeable, allowing substances to pass through.
- The cell membrane is selectively permeable, allowing only selected substances to pass through.
Semi-Permeable Membrane
- A semi-permeable membrane allows certain substances to pass through while restricting others.
- Water molecules can pass through the pores of the membrane, but sugar molecules cannot.
Ascent of Sap
- Water absorbed by root hairs enters the xylem and is transported upwards to the stem and leaves.
- This process is called the ascent of sap.
- The ascent of sap is driven by transpiration, which creates a negative pressure that pulls water upwards.
Factors Affecting Transpiration
- Sunlight: Transpiration rate increases during the day when stomata are open.
- Temperature: High temperatures increase the rate of transpiration.
- Wind: Faster wind speeds increase the rate of transpiration.
- Humidity: High humidity reduces the rate of transpiration.
Importance of Transpiration
- Cooling effect: Transpiration helps plants cool themselves by evaporating water.
- Maintaining sap concentration: Transpiration helps maintain the concentration of sap inside the plant body.
Uses of Water in Plants
- Transportation: Water transports substances in a solution form within the plant.
- Food production: Water is used in photosynthesis to produce glucose and oxygen.
- Cooling: Transpiration produces a cooling effect, making the air cooler and more pleasant.
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Description
This quiz covers the structure and function of the root system in plants, including the main root, lateral roots, and root hairs.