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TRANSPORT IN PLANTS - Q&A

REVIEW QUESTIONS

Multiple Choice Questions :

1. Put a tick mark (✓) against the correct alternative in the following statements :

(a) Diffusion occurs when molecules move :
(i) from lower concentration to higher concentration.
(ii) from higher concentration to lower concentration through a membrane.
(iii) from higher concentration to lower concentration.
(iv) when energy is used.
Answer: (iii) from higher concentration to lower concentration.
Explanation: Diffusion is the free movement of molecules of gas, liquid, or solid from a region of their higher concentration to a region of lower concentration until they are spread evenly.

(b) Ascent of sap in plants takes place through :
(i) Cortex
(ii) Epidermis
(iii) Xylem
(iv) Phloem
Answer: (iii) Xylem
Explanation: Xylem vessels and tracheids help in the upward conduction of water and dissolved minerals (sap) from roots to the leaves.

(c) If the xylem vessels of a plant are plugged :
(i) The leaves will turn yellow
(ii) No food will be made
(iii) The plant will wilt (shrivel)
(iv) The plant will continue to grow
Answer: (iii) The plant will wilt (shrivel)
Explanation: Since xylem transports water, plugging it stops the water supply to the leaves/stem. Without water maintaining turgor pressure, the plant cells collapse, causing wilting.

(d) Force responsible for the ascent of sap is :
(i) Capillary force
(ii) Root pressure
(iii) Transpirational pull
(iv) All the three
Answer: (iv) All the three
Explanation: While transpirational pull is the main force in tall trees, root pressure and capillary force also contribute to the upward movement of water (ascent of sap).

(e) Raisins swell when put in :
(i) Rain water
(ii) Tap water
(iii) Mustard oil
(iv) Saturated sugar solution
Answer: (i) Rain water
Explanation: Rain water is essentially pure water (hypotonic solution). Water moves into the raisins (which have a higher concentration of sugars/solutes inside) by endosmosis, causing them to swell. Tap water works too, but rain water is the purest form here.

(f) The root-hairs are suited for absorbing water from the soil because :
(i) They have a large surface area.
(ii) They have a semi-permeable membrane.
(iii) They contain a solution of higher concentration than the surrounding water.
(iv) All the three.
Answer: (iv) All the three.
Explanation: According to the text (Page 4), root hairs have three specialties: large surface area, high concentration of cell sap, and a semi-permeable cell membrane.

(g) Transpiration is defined as
(i) the rise of water up to the stem of a plant.
(ii) the elimination of water with dissolved water products.
(iii) the loss of water as water vapour from the aerial parts of a plant.
(iv) the loss of water as water vapour from the roots as well as the leaves of the plant.
Answer: (iii) the loss of water as water vapour from the aerial parts of a plant.
Explanation: Transpiration specifically refers to evaporation from aerial parts (mainly leaves), not roots.

(h) Which one of the following favours the fastest transpiration rate ?
(i) A cool, humid, windy day,
(ii) A hot, humid, windy day,
(iii) A hot, humid, still day,
(iv) A hot, dry, windy day.
Answer: (iv) A hot, dry, windy day.
Explanation: High temperature, low humidity (dry), and wind all increase the rate of evaporation, thus increasing transpiration.

Short Answer Questions :

1. An experiment was set up as shown in the figure below. After some time, the water level in test tube A fell down but not in test tube B. Why was there a fall in the water level of test tube A and not in that of test-tube B ?
Answer:
There was a fall in the water level of test tube A because it contained a plant with intact roots. The roots absorbed the water for the plant's physiological activities (photosynthesis) and loss through transpiration.
In test tube B, there was no plant (or roots) to absorb the water. The layer of oil on the surface prevented physical evaporation of water. Therefore, the water level remained unchanged.

2. How are roots useful to the plants ? Give any two points.
Answer:
1. Absorption: Roots absorb water and dissolved minerals from the soil which are essential for the plant's growth and food production.
2. Anchorage (Fixation): Roots fix the plant firmly to the ground, preventing it from falling over.

3. What do xylem vessels carry ?
Answer:
Xylem vessels carry water and dissolved minerals absorbed by the roots from the soil to the leaves and other parts of the plant.

4. Name the plant tissue which helps in carrying the food to different parts.
Answer:
Phloem is the plant tissue that transports food (manufactured by leaves) to various parts of the plant.

5. Define the terms : (a) semi-permeable membrane (b) osmosis.
Answer:
(a) Semi-permeable membrane: It is a membrane that allows water molecules (solvent) to pass through it but prevents the passage of larger molecules (solutes).
(b) Osmosis: It is the movement of water molecules from a region of their higher concentration (dilute solution) to a region of their lower concentration (concentrated solution) through a semi-permeable membrane.

6. Under what conditions do the plant transpire (a) more quickly and (b) most slowly ?
Answer:
(a) More quickly: Transpiration is faster when it is sunny (sunlight), hot (high temperature), windy, and the air is dry (low humidity).
(b) Most slowly: Transpiration is slowest when it is dark (night), cool (low temperature), still air (no wind), and the air is humid (high humidity).

7. Given alongside is an enlarged diagram of a part of the root. Draw arrows on the diagram to show the movement of water passing through different parts.
Answer:
(Note: Since I cannot draw on the image, I will describe the path where arrows should be drawn.)
Arrows should be drawn originating from the Soil, entering the Root-hair, moving through the Root cells (Cortex), and finally entering the central vascular tissue (Xylem).
Path: Soil → Root Hair → Inner Root Cells (Cortex/Endodermis) → Xylem vessels.

8. The structure of the root-hair is quite suitable for absorbing water from the soil. Briefly explain.
Answer:
The root-hair is suited for absorption because:
1. Large Surface Area: The long, hair-like extension increases the surface area for maximum absorption.
2. High Concentration: The cell sap inside the root hair has a higher concentration of salts than the surrounding soil water, allowing water to enter by osmosis.
3. Semi-permeable Membrane: It has a thin, permeable cell wall and a semi-permeable cell membrane that regulates the entry of water and minerals.

9. Briefly explain, how transpiration helps in upward conduction of water in plants ?
Answer:
(a) During transpiration, water evaporates from the leaves, creating a vacuum or suction pressure in the leaf cells.
(b) This suction force, known as transpirational pull, pulls water up from the xylem vessels of the stem, similar to sucking a cold drink through a straw. This force extends down to the roots, causing the upward conduction of water (ascent of sap).

10. How does temperature, light intensity and wind affect transpiration ?
Answer:
1. Temperature: Higher temperatures increase the rate of evaporation, thus increasing transpiration.
2. Light intensity: Sunlight causes stomata to open to allow carbon dioxide in for photosynthesis. Open stomata allow water vapour to escape, increasing transpiration. During the night (no light), stomata close and transpiration stops or reduces.
3. Wind: Moving air (wind) sweeps away water vapour from the leaves, preventing humidity build-up around the leaf. This increases the rate of transpiration.

11. An apparatus shown alongside was set up in sunlight for about an hour. It was observed that drops of water appeared on the inside of the polythene bag.
(a) Name the process which is being demonstrated.
Answer: Transpiration.

(b) Why was the pot and its soil left uncovered by the polythene bag ?
Answer: The pot and soil were left uncovered (and only the aerial plant parts covered) to ensure that the water droplets forming in the bag came only from the plant leaves through transpiration, and not from the evaporation of water from the soil in the pot.

(c) Why was the pot left in sunlight ?
Answer: Sunlight stimulates the opening of stomata for photosynthesis, which increases the rate of transpiration, making the result (water droplets) visible more quickly.

(d) Suppose that the pot in this experiment was placed inside a dark room instead of placing it in sunlight for some time. What difference would be noticed ?
Answer: If placed in a dark room, the stomata would close, and the rate of transpiration would be negligible. Consequently, very few or no water droplets would appear on the inside of the polythene bag.

12. State whether the following statements are True or False. Rewrite the false statements correctly.
(a) Water absorption mainly occurs through the root-hair.
Answer: True.

(b) Water enters the root-hair by osmosis.
Answer: True.

(c) Water absorbed by the roots reaches the leaves and is used in producing food for the entire plant.
Answer: True.

(d) A semi-permeable membrane allows larger molecules to pass through, but prevents the smaller ones.
Answer: False.
Correct Statement: A semi-permeable membrane allows smaller molecules (like water) to pass through, but prevents the larger ones (like sugar/solutes).

(e) Transpiration is the loss of water from the roots of the plant.
Answer: False.
Correct Statement: Transpiration is the loss of water from the aerial parts (leaves/stem) of the plant.

(f) During transpiration, the leaves lose more water from their upper surface.
Answer: False.
Correct Statement: During transpiration, the leaves lose more water from their lower surface (as stomata are usually more numerous on the lower surface).

(g) Transpiration cools the plant when it is hot outside.
Answer: True.

13. Fill in the blanks with suitable terms given below :
(Fast, Leaves, Stomata, Conducting, Ascent, Humid)

(a) Transportation in plants is carried out by a conducting system.
(b) The upward movment of sap that contains water and minerals is called ascent of sap.
(c) The leaves have more stomata on their lower surface.
(d) Transpiration is more when the wind is blowing fast.
(e) Most water gets evaporated from the plant from its leaves.
(f) Transpiration is reduced if the air is humid.

Long Answer Questions (Write the answers in your notebook) :

1. Draw a magnified view of the root-hair, and describe how it helps in the absorption of water from the soil ?
Answer:
(Refer to Figure 1.5 in the textbook for the diagram)
Description:
A root-hair is a long, delicate protuberance of an epidermal cell of the root. It contains cell sap which has a higher concentration of salts compared to the surrounding soil water. The root-hair has a semi-permeable membrane. Because of the concentration difference (osmosis), water moves from the soil (lower concentration) into the root-hair (higher concentration). This water is then passed to inner cells.

2. How does transpiration help the roots absorb water and minerals from the soil ?
Answer:
Transpiration creates a suction force (transpirational pull) in the leaves due to water loss. This suction travels down the stem to the roots. It acts like a pump, actively pulling water and dissolved minerals from the soil into the roots to replace the water lost by the leaves.

3. Describe the three processes by which plants absorb water and minerals from the soil.
Answer:
1. Diffusion: The movement of mineral ions and water molecules from regions of higher concentration in the soil to the root cells.
2. Osmosis: The movement of water molecules from the soil (dilute solution) into the root hair (concentrated solution) through the semi-permeable cell membrane.
3. Active Transport: The absorption of minerals against the concentration gradient (from low concentration in soil to high in roots), which requires the expenditure of energy by the plant.

4. How is water absorbed by the roots important for the plants ?
Answer:
1. Food Production: Water is a raw material required for photosynthesis to produce glucose.
2. Transportation: It acts as a medium to transport minerals and food to different plant parts.
3. Cooling: Transpiration of absorbed water cools the plant.
4. Mechanical Stiffness: It provides turgidity (stiffness) to cells, helping the plant stand upright.

5. Describe the factors which affect the rate of transpiration ?
Answer:
1. Sunlight: Opens stomata, increasing transpiration.
2. Temperature: Higher heat causes faster evaporation of water.
3. Wind: Fast wind removes moisture around leaves, speeding up transpiration.
4. Humidity: High humidity reduces evaporation, slowing down transpiration.

6. Mention the two ways in which transpiration helps the plants.
Answer:
1. Cooling Effect: Evaporation of water takes heat from the plant, preventing it from overheating in hot sun.
2. Transpirational Pull: It creates a suction force that helps in the upward transport of water and minerals (ascent of sap) from roots to the top of the plant.

7. Describe an experiment to show that the plant loses water through its leaves.
Answer:
Take a small, well-watered potted plant. Cover the soil and pot with a rubber sheet (or bag) to prevent evaporation from the soil. Cover the aerial part (leaves/stem) with a clean, dry transparent polythene bag and tie the mouth. Place the set-up in sunlight.
Observation: After a few hours, drops of water appear on the inner surface of the bag.
Conclusion: This water has come from the leaves as vapor and condensed, proving plants lose water through leaves (transpiration).

8. Name any three minerals whose deficiency causes diseases in plants. Give the symptoms of each deficiency.
Answer:
1. Nitrogen: Deficiency causes yellowing of leaves and wrinkling of cereal grains.
2. Phosphorus: Deficiency causes purple and red spots on leaves and delay in seed germination.
3. Iron: Deficiency causes yellowing of leaves (chlorosis).

9. Name the different types of cells found in xylem and phloem and give their functions.
Answer:
Xylem Cells:
1. Tracheids & Vessels: Tubular structures that transport water and minerals vertically.
2. Xylem Fibres: Provide mechanical support.
3. Xylem Parenchyma: Stores food.

Phloem Cells:
1. Sieve Tubes: Transport organic food vertically.
2. Companion Cells: Help sieve tubes in conduction.
3. Phloem Parenchyma: Stores food.
4. Phloem Fibres: Provide mechanical strength.
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Multiple Choice Questions - Test your understanding with these MCQs. Click "Show Answer" to reveal the correct answer.

Question 1Which of the following processes allows plants to prepare their own food?

Correct Answer: Photosynthesis

Question 2What are the two main raw materials used by plants during photosynthesis?

Correct Answer: Carbon dioxide and Water

Question 3How do plants obtain carbon dioxide for food production?

Correct Answer: From the atmosphere through leaves

Question 4Which plant part is primarily responsible for absorbing water and minerals from the soil?

Correct Answer: Roots

Question 5What is the collective term for the conducting tissues xylem and phloem?

Correct Answer: Vascular bundle

Question 6Which tissue forms a tubular passage for the upward conduction of water and minerals?

Correct Answer: Xylem

Question 7Which of these xylem cells are elongated, dead, and have tapering ends?

Correct Answer: Xylem tracheids

Question 8What is the primary function of xylem vessels?

Correct Answer: Lateral and vertical transport of water

Question 9Which component of the xylem tissue is made of living cells?

Correct Answer: Xylem parenchyma

Question 10What is the main role of xylem fibres?

Correct Answer: Providing mechanical support

Question 11Which tissue is specialized to transport organic food manufactured in the leaves?

Correct Answer: Phloem

Question 12Unlike xylem, phloem is described as a ____ tissue.

Correct Answer: Living

Question 13What are the vertical rows of cylindrical cells in phloem that conduct food called?

Correct Answer: Sieve tubes

Question 14What are the perforated end walls of sieve tubes called?

Correct Answer: Sieve plates

Question 15Which phloem cells help sieve tubes in the conduction of food material?

Correct Answer: Companion cells

Question 16Which part of the phloem tissue is responsible for storing food?

Correct Answer: Phloem parenchyma

Question 17In what form is food transported through the phloem?

Correct Answer: Sucrose solution

Question 18The movement of food from leaves to other parts of the plant is called:

Correct Answer: Translocation

Question 19Which property describes the attraction of water molecules toward narrow spaces?

Correct Answer: Capillarity

Question 20What are the fine outgrowths of the root epidermal cells called?

Correct Answer: Root-hairs

Question 21A membrane that allows only water molecules to pass but prevents larger molecules is:

Correct Answer: Semi-permeable

Question 22Why is the cell sap in root-hairs more concentrated than soil water?

Correct Answer: It contains more solutes

Question 23The movement of molecules from a region of higher concentration to lower concentration is:

Correct Answer: Diffusion

Question 24Osmosis specifically refers to the movement of which molecules?

Correct Answer: Water

Question 25In osmosis, water moves from a ______ solution to a ______ solution.

Correct Answer: Dilute, Concentrated

Question 26What process is used when plants absorb minerals against a concentration gradient?

Correct Answer: Active transport

Question 27Active transport is different from diffusion because it requires:

Correct Answer: Energy

Question 28What is the upward movement of water and minerals (sap) called?

Correct Answer: Ascent of sap

Question 29The pressure developed in roots due to continuous inflow of water is:

Correct Answer: Root pressure

Question 30What is the loss of water as water vapour from aerial parts of a plant called?

Correct Answer: Transpiration

Question 31Through which structures in the leaves does most transpiration occur?

Correct Answer: Stomata

Question 32The pulling force created by transpiration that draws water upward is the:

Correct Answer: Transpiration pull

Question 33Which of these factors decreases the rate of transpiration?

Correct Answer: High humidity

Question 34Why is transpiration faster during the daytime?

Correct Answer: Stomata are open for photosynthesis

Question 35How does transpiration provide a cooling effect to the plant?

Correct Answer: By using latent heat for evaporation

Question 36Standing under a tree in summer feels cool primarily due to:

Correct Answer: Transpiration from leaves

Question 37Which category of nutrients is required by plants in larger concentrations?

Correct Answer: Macro-nutrients

Question 38Which of the following is a macro-nutrient?

Correct Answer: Nitrogen

Question 39What is a common deficiency symptom of Nitrogen lack in plants?

Correct Answer: Yellowing of leaves

Question 40Which nutrient is a major constituent of the cell membrane?

Correct Answer: Phosphorus

Question 41Which mineral is involved in the opening and closing of stomata?

Correct Answer: Potassium

Question 42Iron and Zinc are examples of which type of nutrients?

Correct Answer: Micro-nutrients

Question 43A lack of which micro-nutrient causes leaves to become deshaped?

Correct Answer: Zinc

Question 44What happens to raisins when placed in water for 10-12 hours?

Correct Answer: They swell

Question 45Why do grapes shrink when kept in a thick sugar syrup?

Correct Answer: Water moves out by osmosis

Question 46In the experiment with four test tubes (A, B, C, D), why did the water level in 'A' remain unchanged?

Correct Answer: It had no plant

Question 47In the experiment with four test tubes, what happened to the leaves in tube 'D' where roots were not in water?

Correct Answer: They shrivelled up

Question 48What does the appearance of red colour in leaf veins in tube 'C' prove?

Correct Answer: Roots absorb water and transport it to leaves

Question 49Why is oil added to the surface of water in absorption experiments?

Correct Answer: To prevent evaporation from the water surface

Question 50The tendency of water molecules to remain joined together during upward transport is:

Correct Answer: Cohesion
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True or False Questions - Determine whether each statement is true or false. Click "Show Answer" to reveal the correct answer.

Statement 1Plants obtain carbon dioxide from the atmosphere for photosynthesis.

Correct Answer: True

Statement 2Water and minerals are absorbed by plants through their leaves.

Correct Answer: False

Statement 3Transportation in plants involves moving substances from one part of the plant to another.

Correct Answer: True

Statement 4Xylem and phloem together are known as the vascular bundle.

Correct Answer: True

Statement 5Xylem is responsible for transporting food manufactured by leaves.

Correct Answer: False

Statement 6Xylem cells are thick-walled and form a tubular passage.

Correct Answer: True

Statement 7Tracheids are living cells with tapering ends.

Correct Answer: False

Statement 8Xylem vessels are open at both ends.

Correct Answer: True

Statement 9Xylem fibres provide mechanical support to the plant.

Correct Answer: True

Statement 10Xylem parenchyma cells are dead cells used for food storage.

Correct Answer: False

Statement 11The main function of xylem is the upward conduction of water and minerals.

Correct Answer: True

Statement 12Phloem transports organic food from leaves to other parts of the plant.

Correct Answer: True

Statement 13Phloem is a simple tissue made of only one type of cell.

Correct Answer: False

Statement 14Sieve tubes are the main conducting part of the phloem.

Correct Answer: True

Statement 15Sieve plates are perforated end walls of sieve tubes.

Correct Answer: True

Statement 16Companion cells are associated with xylem vessels.

Correct Answer: False

Statement 17Phloem parenchyma helps in the storage of organic food.

Correct Answer: True

Statement 18Phloem fibres are living sclerenchyma cells.

Correct Answer: False

Statement 19In phloem, food material can pass from cell to cell through sieve plates.

Correct Answer: True

Statement 20Roots only absorb water and cannot fix the plant to the ground.

Correct Answer: False

Statement 21The root system consists of a main root and lateral roots.

Correct Answer: True

Statement 22Root-hairs are fine outgrowths of lateral roots.

Correct Answer: True

Statement 23A root-hair is a multi-cellular structure.

Correct Answer: False

Statement 24The cell wall of a root-hair is freely permeable.

Correct Answer: True

Statement 25The cell membrane of a root-hair is semi-permeable.

Correct Answer: True

Statement 26Cell sap in root-hairs is less concentrated than soil water.

Correct Answer: False

Statement 27Root-hairs provide a large surface area for absorption.

Correct Answer: True

Statement 28Diffusion is the movement of molecules from lower to higher concentration.

Correct Answer: False

Statement 29Osmosis involves the movement of water molecules through a semi-permeable membrane.

Correct Answer: True

Statement 30Active transport requires energy to move molecules against a concentration gradient.

Correct Answer: True

Statement 31Minerals are always more concentrated in the soil than inside root-hairs.

Correct Answer: False

Statement 32Ascent of sap refers to the upward movement of water and minerals.

Correct Answer: True

Statement 33Root pressure is developed due to the continuous inflow of water.

Correct Answer: True

Statement 34Transpiration is the loss of water as liquid from the leaves.

Correct Answer: False

Statement 35Transpiration creates a suction pressure that pulls water upwards.

Correct Answer: True

Statement 36Most water absorbed by plants is retained for photosynthesis.

Correct Answer: False

Statement 37Transpiration pull can move water to a height of 100 metres or more.

Correct Answer: True

Statement 38Stomata are generally open during the night.

Correct Answer: False

Statement 39Transpiration rate increases on hot summer days.

Correct Answer: True

Statement 40High humidity increases the rate of transpiration.

Correct Answer: False

Statement 41Fast-blowing wind increases the rate of transpiration.

Correct Answer: True

Statement 42Transpiration has a cooling effect on the plant.

Correct Answer: True

Statement 43Water is a raw material for food production in plants.

Correct Answer: True

Statement 44Evaporation of water from leaves makes the surrounding air warmer.

Correct Answer: False

Statement 45Macro-nutrients are required by plants in very small amounts.

Correct Answer: False

Statement 46Micro-nutrients are also known as trace elements.

Correct Answer: True

Statement 47Nitrogen is a major constituent of all proteins.

Correct Answer: True

Statement 48Phosphorus deficiency causes yellowing of leaves.

Correct Answer: False

Statement 49Potassium is involved in the opening and closing of stomata.

Correct Answer: True

Statement 50Iron is a micro-nutrient required by plants.

Correct Answer: True
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Fill in the Blanks - Complete the sentences by filling in the missing words. Click "Show Answer" to check your response.

Question 1Plants prepare their own food by a process called ______.

Correct Answer: photosynthesis

Question 2Water along with minerals is absorbed from the soil through the ______.

Correct Answer: roots

Question 3Transportation in plants is carried out by a conducting system consisting of two tissues: ______ and phloem.

Correct Answer: xylem

Question 4Xylem and phloem together are also called the ______.

Correct Answer: vascular bundle

Question 5Xylem cells form a ______ passage for water and minerals absorbed from the soil.

Correct Answer: tubular

Question 6The xylem tissue consists of four types of cells: tracheids, vessels, xylem fibres, and ______.

Correct Answer: xylem parenchyma

Question 7______ are elongated dead cells with tapering ends and thickened walls.

Correct Answer: Tracheids

Question 8Xylem ______ are tube-like structures placed one above the other forming long channels.

Correct Answer: vessels

Question 9Xylem vessels are ______ at both ends.

Correct Answer: open

Question 10Xylem ______ are sclerenchymatous and provide only mechanical support.

Correct Answer: fibres

Question 11Xylem parenchyma are ______ cells that help in conduction and store food.

Correct Answer: living

Question 12The main function of xylem is the ______ conduction of water and minerals.

Correct Answer: upward

Question 13Phloem is a complex permanent tissue specialized to transport ______ food.

Correct Answer: organic

Question 14Phloem consists of four types of cells: sieve tubes, companion cells, phloem parenchyma, and ______.

Correct Answer: phloem fibres

Question 15______ form the main conducting part of the phloem.

Correct Answer: Sieve tubes

Question 16The end walls of sieve tubes are perforated and are called ______.

Correct Answer: sieve plates

Question 17Associated with sieve tubes are thin-walled parenchymatous cells called ______ cells.

Correct Answer: companion

Question 18The ______ companion cells help sieve tubes in the conduction of food material.

Correct Answer: adjacent

Question 19Phloem ______ is formed of dead sclerenchyma cells that provide mechanical strength.

Correct Answer: fibres

Question 20Phloem parenchyma helps in the ______ of organic food.

Correct Answer: storage

Question 21In the phloem, food is transported both ______ and downwards.

Correct Answer: upwards

Question 22The transport of food in plants is also called ______ of solutes.

Correct Answer: translocation

Question 23Plants produce food as glucose, which is stored in the form of ______.

Correct Answer: starch

Question 24Food is transported through the phloem in the form of a ______ solution.

Correct Answer: sucrose

Question 25The root system consists of a main root which gives out ______ roots.

Correct Answer: lateral

Question 26Lateral roots bear a large number of fine outgrowths called ______.

Correct Answer: root-hairs

Question 27A root-hair is a long protuberance of an ______ cell of the root.

Correct Answer: epidermal

Question 28The root-hair cell wall is ______ permeable, allowing all substances to pass.

Correct Answer: freely

Question 29The inner cell membrane of a root-hair is ______-permeable.

Correct Answer: semi

Question 30Root-hairs provide a large ______ area for greater absorption.

Correct Answer: surface

Question 31Root-hairs contain ______ which is of a higher concentration than soil water.

Correct Answer: cell sap

Question 32The simple movement of molecules from higher concentration to lower concentration is called ______.

Correct Answer: diffusion

Question 33______ is the movement of water molecules from a dilute solution to a concentrated solution across a semi-permeable membrane.

Correct Answer: Osmosis

Question 34Soil water and minerals move into the ______ by the process of diffusion.

Correct Answer: cell wall

Question 35Water enters the root-hair cell by ______.

Correct Answer: osmosis

Question 36The movement of molecules from a lower to a higher concentration using energy is called ______.

Correct Answer: active transport

Question 37Water moves into deeper parts of the root by cell-to-cell osmosis until it reaches the ______.

Correct Answer: xylem

Question 38The upward movement of water and minerals (sap) is called ______ of sap.

Correct Answer: ascent

Question 39The pressure developed in the root due to continuous inflow of water is called ______.

Correct Answer: root pressure

Question 40The loss of water as water vapour from the aerial parts of a plant is called ______.

Correct Answer: transpiration

Question 41Most transpiration occurs through the ______ present in the epidermis of leaves.

Correct Answer: stomata

Question 42Transpiration creates a ______ pressure which pulls up water from the roots.

Correct Answer: suction

Question 43The pulling force caused by transpiration is known as ______.

Correct Answer: transpiration pull

Question 44Water molecules are pulled up due to their tendency to remain joined, known as ______.

Correct Answer: cohesion

Question 45During the ______, the rate of transpiration is faster because stomata are open.

Correct Answer: daytime

Question 46Transpiration is ______ on hot summer days compared to cold winters.

Correct Answer: faster

Question 47If the air is ______, the rate of transpiration is reduced.

Correct Answer: humid

Question 48When the wind blows faster, transpiration ______.

Correct Answer: increases

Question 49Transpiration produces a ______ effect, helping the plant when it is hot outside.

Correct Answer: cooling

Question 50Transpiration helps in maintaining the ______ of the sap inside the plant.

Correct Answer: concentration
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Short Answer Questions - Practice concise answers to these questions. Click "Show Answer" to reveal the response.
Question 1

What is the process by which plants prepare their own food?

Answer:
Photosynthesis
Question 2

From where do plants get water and minerals?

Answer:
Soil
Question 3

What are the two main tissues of the plant conducting system?

Answer:
Xylem and Phloem
Question 4

What is another name for the conducting system consisting of xylem and phloem?

Answer:
Vascular bundle
Question 5

Which tissue transports water and minerals upwards?

Answer:
Xylem
Question 6

Which tissue transports manufactured food to all plant parts?

Answer:
Phloem
Question 7

Are xylem tracheids living or dead cells?

Answer:
Dead
Question 8

Which xylem cells are responsible for storing food?

Answer:
Xylem parenchyma
Question 9

What shape are xylem tracheids at their ends?

Answer:
Tapering
Question 10

What are the tube-like structures in xylem placed one above the other?

Answer:
Xylem vessels
Question 11

Which xylem component provides only mechanical support?

Answer:
Xylem fibres
Question 12

In which direction does xylem primarily conduct water?

Answer:
Upward
Question 13

Is phloem a living or dead tissue?

Answer:
Living tissue
Question 14

What are the main conducting cells of the phloem?

Answer:
Sieve tubes
Question 15

What are the perforated end walls of sieve tubes called?

Answer:
Sieve plates
Question 16

Which phloem cells help sieve tubes in food conduction?

Answer:
Companion cells
Question 17

Which phloem cells provide mechanical strength?

Answer:
Phloem fibres
Question 18

What form of food is produced during photosynthesis?

Answer:
Glucose
Question 19

In what form is food stored in plants?

Answer:
Starch
Question 20

In what form is food transported through phloem?

Answer:
Sucrose solution
Question 21

What is the movement of food through phloem called?

Answer:
Translocation
Question 22

Which part of the plant is responsible for absorbing water?

Answer:
Roots
Question 23

What are the fine outgrowths on lateral roots called?

Answer:
Root-hairs
Question 24

A root-hair is an extension of which type of cell?

Answer:
Epidermal cell
Question 25

Is the root-hair cell wall freely permeable or semi-permeable?

Answer:
Freely permeable
Question 26

Is the root-hair cell membrane freely permeable or semi-permeable?

Answer:
Semi-permeable
Question 27

What is the fluid inside the root-hair cell called?

Answer:
Cell sap
Question 28

Is cell sap more or less concentrated than soil water?

Answer:
More concentrated
Question 29

What term describes the movement of molecules from higher to lower concentration?

Answer:
Diffusion
Question 30

What is the movement of water from dilute to concentrated solution through a membrane?

Answer:
Osmosis
Question 31

Which process requires energy to move minerals against a concentration gradient?

Answer:
Active transport
Question 32

What happens to raisins when kept in water for several hours?

Answer:
They swell
Question 33

What happens to grapes when kept in thick sugar syrup?

Answer:
They shrink
Question 34

By what process does soil water enter the root-hair cell wall?

Answer:
Diffusion
Question 35

By what process does water enter the root-hair cytoplasm?

Answer:
Osmosis
Question 36

What is the upward movement of water and minerals called?

Answer:
Ascent of sap
Question 37

What pressure is built up in roots due to water inflow?

Answer:
Root pressure
Question 38

What is the loss of water vapour from aerial parts of a plant called?

Answer:
Transpiration
Question 39

Through which pores does most transpiration occur?

Answer:
Stomata
Question 40

In which part of the leaf are stomata mainly located?

Answer:
Epidermis
Question 41

What pulling force is created by transpiration?

Answer:
Transpiration pull
Question 42

What property keeps water molecules joined together during upward movement?

Answer:
Cohesion
Question 43

Does transpiration happen faster during the day or night?

Answer:
Day
Question 44

How does high temperature affect the rate of transpiration?

Answer:
Increases it
Question 45

How does high humidity affect the rate of transpiration?

Answer:
Reduces it
Question 46

How does fast-moving wind affect transpiration?

Answer:
Increases it
Question 47

Name one major importance of transpiration for a plant.

Answer:
Cooling effect
Question 48

What term refers to the attraction of water molecules to narrow spaces?

Answer:
Capillarity
Question 49

Which minerals are required by plants in large concentrations?

Answer:
Macro-nutrients
Question 50

Which minerals are required by plants in very small amounts?

Answer:
Micro-nutrients
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Long Answer Questions - Practice detailed answers to these comprehensive questions. Click "Show Answer" to reveal the response.
Question 1

Define transportation in plants and identify the two main tissues involved in this process.

Answer:
Transportation in plants is the process by which substances absorbed or synthesized in one part of the plant are moved to other parts of the plant. This process is carried out by a conducting system consisting of two specialized tissues:
1. Xylem: Responsible for the upward conduction of water and dissolved minerals from the roots to the leaves.
2. Phloem: Responsible for transporting organic food manufactured in the leaves to all other parts of the plant, including the roots.
Question 2

Describe the structure and functions of the four types of cells that make up xylem tissue.

Answer:
Xylem is a complex tissue consisting of four types of cells:
1. Xylem Tracheids: Elongated dead cells with tapering ends and thickened walls. They conduct water upwards and provide mechanical support.
2. Xylem Vessels: Tube-like structures placed end-to-end forming long channels. They are open at both ends and transport water and minerals vertically and laterally while providing support.
3. Xylem Fibres: Long, narrow sclerenchymatous cells that provide only mechanical support to the plant.
4. Xylem Parenchyma: Living cells that assist in the conduction of water and minerals and serve as storage for food.
Question 3

Explain the composition of phloem tissue and the specific function of each cell type.

Answer:
Phloem is composed of four types of cells, both living and dead:
1. Sieve Tubes: Cylindrical cells joined end-to-end with perforated end walls called sieve plates. They are the main conducting channels for food.
2. Companion Cells: Thin-walled parenchymatous cells associated with sieve tubes that assist in the conduction of food.
3. Phloem Parenchyma: Living cells that function primarily in the storage of organic food.
4. Phloem Fibres: Dead sclerenchyma cells that provide mechanical strength to the plant.
Question 4

What are root-hairs? Explain three ways in which they are suited for absorbing water from the soil.

Answer:
Root-hairs are long, fine protuberances of the epidermal cells of the root. They are suited for absorption in the following ways:
1. Large Surface Area: The vast number of root-hairs significantly increases the surface area, allowing for greater absorption of water.
2. High Concentration of Cell Sap: The cell sap inside root-hairs is more concentrated than the surrounding soil water, which facilitates osmosis.
3. Permeability: The cell wall is fully permeable, allowing all substances to enter, while the cell membrane is semi-permeable, specifically regulating the entry of water molecules.
Question 5

Differentiate between Diffusion, Osmosis, and Active Transport in the context of plant absorption.

Answer:
1. Diffusion: The movement of molecules (gas, liquid, or solid) from a region of higher concentration to lower concentration. It allows water and minerals to enter the cell wall.
2. Osmosis: The movement of water molecules from a dilute solution (higher water concentration) to a concentrated solution (lower water concentration) through a semi-permeable membrane.
3. Active Transport: The movement of molecules (like minerals) from a region of lower concentration to higher concentration against a gradient. This process requires the expenditure of energy by the plant.
Question 6

Define 'Ascent of Sap' and explain the forces that contribute to this phenomenon.

Answer:
Ascent of Sap is the upward movement of water and dissolved minerals from the roots to the leaves and other aerial parts. Several forces contribute to this:
1. Root Pressure: The pressure developed in the roots due to continuous inflow of water via osmosis, pushing sap upwards.
2. Transpiration Pull: As water evaporates from leaves, it creates a suction force that pulls the water column upward.
3. Cohesion: The tendency of water molecules to remain joined together, allowing an unbroken column of water to be pulled to great heights.
4. Capillarity: The attraction of water molecules to the narrow walls of xylem vessels.
Question 7

Define transpiration and list the external factors that affect its rate.

Answer:
Transpiration is the loss of water in the form of water vapour from the aerial parts (mainly leaves) of a plant. The factors affecting its rate include:
1. Sunlight: Rate is faster during the day as stomata open for photosynthesis.
2. Temperature: Higher temperatures increase the rate of evaporation.
3. Wind: Moving air carries away water vapour faster, increasing transpiration.
4. Humidity: High humidity in the air reduces the rate because the air is already laden with moisture.
Question 8

Discuss the importance of transpiration to a plant's survival.

Answer:
Transpiration is vital for several reasons:
1. Cooling Effect: Evaporation consumes heat from the plant, cooling it down in hot weather.
2. Creating Suction Force: It generates the transpirational pull necessary for the upward movement of water and minerals.
3. Maintaining Concentration: By removing excess water, it ensures the cell sap remains concentrated enough to continue absorbing minerals from the soil.
4. Distribution of Water: It facilitates the movement of water to all parts of the plant for photosynthesis.
Question 9

Describe an experiment to demonstrate that roots are the primary organs for water absorption.

Answer:
1. Take four test tubes (A, B, C, D). Tube A contains only water (control).
2. Tube B and C contain water with oil on top. Insert a small plant in each so roots are submerged.
3. Tube D contains very little water so that the roots of the inserted plant remain above the water level.
4. Add a red dye to Tube C. After 24 hours, observe.
5. Results: Water levels in B and C fall because roots absorbed water. In C, leaf veins turn red, showing water reached the leaves. In D, the plant shrivels because the roots could not reach the water, proving that leaves/stems alone cannot absorb water.
Question 10

Explain the difference between macro-nutrients and micro-nutrients, providing examples of each.

Answer:
1. Macro-nutrients: These are essential elements required by plants in relatively large concentrations. Examples include Nitrogen (constituent of proteins), Phosphorus (part of cell membranes), and Potassium (involved in stomatal movement).
2. Micro-nutrients: These are essential elements required in very small or trace amounts. Examples include Iron (constituent of proteins), Manganese (activates enzymes), and Zinc (constituent of plant hormones).
Question 11

Describe the deficiency symptoms of Nitrogen, Phosphorus, and Potassium in plants.

Answer:
1. Nitrogen Deficiency: Leads to the yellowing of leaves (chlorosis) and the wrinkling of cereal grains.
2. Phosphorus Deficiency: Causes purple and red spots on leaves and results in a delay in seed germination.
3. Potassium Deficiency: Leads to overall poor growth of the plant and affects the regulation of stomatal opening and closing.
Question 12

Explain the role of 'Root Pressure' in the conduction of water.

Answer:
Root pressure is the hydrostatic pressure built up in the xylem of the roots. It is created by the active absorption of minerals and the subsequent osmotic entry of water into the root cells. This continuous inflow of water pushes the sap into the xylem vessels and forces it upward through the stem. While it helps in the ascent of sap, it is generally only sufficient to push water up to a certain limited height.
Question 13

How does the structure of a sieve tube element facilitate the transport of food?

Answer:
Sieve tube elements are specialized cells in the phloem. Their structure facilitates food transport because:
1. They are elongated cells arranged in vertical rows, forming a continuous channel.
2. Their end walls, known as sieve plates, are perforated with pores. This allows phloem sap (sucrose solution) to flow easily from one cell to the next.
3. They lack a nucleus at maturity, which provides more space for the flow of organic solutes.
Question 14

Describe an experiment to show that water is lost through the leaves during transpiration.

Answer:
1. Take a well-watered potted plant with two branches.
2. Cover branch A (with leaves intact) with a transparent polythene bag and tie it tightly at the base.
3. Remove all leaves from branch B and cover it with a similar polythene bag.
4. Place the plant in sunlight for 4-6 hours.
5. Observation: Droplets of water appear on the inner surface of bag A, while bag B remains dry. This proves that water is lost specifically through the leaves of the plant.
Question 15

Why is the cell membrane of a root-hair described as semi-permeable?

Answer:
The cell membrane of a root-hair is described as semi-permeable because it is selectively restrictive. It possesses very minute pores that allow small molecules, such as water, to pass through freely. However, it prevents the passage of larger molecules, such as dissolved sugars or large proteins, from the cell sap out into the soil. This property is essential for the process of osmosis.
Question 16

Identify the three main uses of water within a plant body.

Answer:
1. Transportation: Water acts as a solvent to carry minerals in the xylem and sugars in the phloem to different parts of the plant.
2. Food Production: Water is a raw material for photosynthesis, where it combines with carbon dioxide to produce glucose.
3. Cooling: Through the process of transpiration, water evaporation helps regulate the plant's internal temperature.
Question 17

How does a 'Transpiration Pull' work in tall trees reaching heights of 100 metres?

Answer:
In tall trees, the transpiration pull is the primary force for water movement. As water evaporates from the mesophyll cells in the leaves into the atmosphere, it creates a negative pressure or suction. Because water molecules are cohesive (they stick together), this suction is transmitted all the way down the xylem to the roots. This creates a continuous 'water chain' that pulls water upward from the soil to the highest leaves.
Question 18

What would happen to a plant if its phloem tissue was damaged or removed?

Answer:
If the phloem is damaged, the translocation of organic food (sugars) would stop. Food manufactured in the leaves would be unable to reach the roots and other non-photosynthetic storage organs. Consequently, the roots would starve and eventually die. Since the roots would no longer be able to absorb water and minerals without energy, the entire plant would eventually wilt and perish.
Question 19

Discuss the role of Xylem Parenchyma and Phloem Parenchyma.

Answer:
1. Xylem Parenchyma: These are the only living cells in the xylem. They assist in the lateral conduction of water and minerals and are involved in the storage of starch and fats.
2. Phloem Parenchyma: These are thin-walled living cells in the phloem. Their primary function is to store food and other substances like resins and latex, and they also help in the slow lateral conduction of food.
Question 20

Explain how humidity in the atmosphere regulates the rate of transpiration.

Answer:
Humidity is the amount of water vapour present in the air. Transpiration is a process of diffusion of water vapour from the leaf (high concentration) to the air (low concentration). If the atmosphere is highly humid, the concentration gradient between the inside of the leaf and the outside air is low. The air cannot hold much more moisture, thus significantly reducing the rate of transpiration.
Question 21

Describe the process of osmosis using the example of raisins placed in water.

Answer:
When dry raisins are placed in water, the concentration of water is higher outside the raisin than inside (where there is concentrated sugar). The raisin's peel acts as a semi-permeable membrane. Water molecules move from the beaker (higher water concentration) into the raisin (lower water concentration) through the peel. This causes the raisins to swell, demonstrating osmosis.
Question 22

What are the characteristics of Xylem Vessels?

Answer:
Xylem vessels are characterized by:
1. Being long, tube-like structures formed by many cells joined end-to-end.
2. Having cells that are dead and empty of protoplasm at maturity.
3. Having walls thickened with lignin for mechanical strength.
4. Having end walls that are completely dissolved, creating a continuous pipe for water flow.
Question 23

How do companion cells assist sieve tubes in the phloem?

Answer:
Sieve tubes lack a nucleus at maturity and have very few organelles to allow for maximum space for food transport. Companion cells, which are living parenchymatous cells with a prominent nucleus and dense cytoplasm, remain physically and metabolically connected to the sieve tubes. They provide the metabolic energy and proteins necessary for the sieve tubes to function and transport food effectively.
Question 24

Explain 'Capillarity' and its role in plant transport.

Answer:
Capillarity is the phenomenon where a liquid rises in a very narrow tube due to the forces of adhesion (attraction between water and tube walls) and surface tension. In plants, the xylem vessels act as capillary tubes. When water is lost from the top, the capillary force helps water from below rise into the narrow vessels, contributing to the upward movement of the sap column.
Question 25

Why is active transport necessary for mineral absorption in plants?

Answer:
Active transport is necessary because the concentration of minerals in the soil is often lower than the concentration of minerals already present inside the root-hair cells. According to the laws of diffusion, minerals would naturally move out of the root. To bring more minerals in against this concentration gradient, the plant must use energy to 'pump' them into the cells.
Question 26

List the deficiency diseases and symptoms associated with the micro-nutrients Iron, Manganese, and Zinc.

Answer:
1. Iron (Fe): Deficiency causes the yellowing of leaves (chlorosis).
2. Manganese (Mn): Deficiency leads to the yellowing of leaves accompanied by grey spots.
3. Zinc (Zn): Deficiency causes deshaped leaves, yellowing, and stunted plant growth.
Question 27

Briefly describe the 'Cohesion-Adhesion' theory of water movement.

Answer:
This theory explains how water reaches the top of tall trees. Cohesion is the mutual attraction between water molecules that creates a solid water column. Adhesion is the attraction between water molecules and the xylem wall which prevents the column from breaking under gravity. Together with transpiration pull, these forces allow a continuous stream of water to move upward without snapping.
Question 28

How does light intensity affect the rate of transpiration?

Answer:
Light intensity directly affects transpiration because the stomata (pores on the leaf) usually open in the presence of light to allow carbon dioxide to enter for photosynthesis. As light intensity increases, stomata open wider, and the internal temperature of the leaf may rise, both of which lead to a faster rate of transpiration.
Question 29

Differentiate between the cell wall and cell membrane of a root-hair cell.

Answer:
1. Cell Wall: It is the outermost layer, made of cellulose, and is 'freely permeable,' meaning it allows water and all dissolved solutes to pass through without selection.
2. Cell Membrane: It lies inside the cell wall and is 'semi-permeable' (or selectively permeable). it allows water molecules to pass but restricts larger solute molecules, enabling the cell to maintain osmotic balance.
Question 30

What is the role of phloem sap, and what does it consist of?

Answer:
Phloem sap is the fluid that circulates through the phloem tissue. Its primary role is to distribute nutrients, mainly the sugars produced during photosynthesis, to the rest of the plant. It consists mostly of water and sucrose, but also contains minerals, amino acids, and plant hormones being translocated to various growing or storage regions.
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Quick Review Flashcards - Click to flip and test your knowledge!
Question
What is the process by which plants prepare their own food?
Answer
Photosynthesis.
Question
What are the two main substances plants use from the environment for photosynthesis?
Answer
Carbon dioxide from the atmosphere and water from the soil.
Question
Transportation in plants is carried out by a conducting system consisting of two tissues called _____ and _____.
Answer
xylem, phloem
Question
What is the collective term for the conducting tissues, xylem and phloem, in a plant?
Answer
Vascular bundle.
Question
What is the primary function of xylem tissue in a plant?
Answer
It forms a continuous passage for water and minerals absorbed by the roots to reach other parts of the plant.
Question
Name the four types of cells that constitute xylem tissue.
Answer
Tracheids, vessels, xylem fibres, and xylem parenchyma.
Question
What are tracheids in xylem?
Answer
Elongated dead cells with tapering ends that help in the upward conduction of water and provide mechanical support.
Question
What are vessels in xylem?
Answer
Tube-like structures placed one above the other, forming long channels for transporting water and mineral salts vertically.
Question
What is the function of xylem fibres?
Answer
They are sclerenchymatous fibres that provide only mechanical support.
Question
What is the function of xylem parenchyma?
Answer
These are living cells that help in the conduction of water and minerals and serve for the storage of food.
Question
What is the primary function of phloem tissue?
Answer
To transport organic food manufactured by leaves to various parts of the plant.
Question
Name the four types of cells that constitute phloem tissue.
Answer
Sieve tubes, companion cells, phloem parenchyma, and phloem fibres.
Question
What are sieve tubes in phloem?
Answer
Cylindrical cells arranged in vertical rows, joined end to end, with perforated end walls called sieve plates, forming the main conducting part.
Question
What is the function of companion cells in phloem?
Answer
They are elongated, thin-walled parenchymatous cells associated with sieve tubes, helping them in the conduction of food material.
Question
What is the function of phloem parenchyma?
Answer
These cells are formed of thin-walled unspecialized parenchymatous cells and are responsible for storing food.
Question
What is the function of phloem fibres?
Answer
They are dead sclerenchyma fibres that provide mechanical strength to the phloem.
Question
In the experiment to show that only roots absorb water, why is a layer of oil added to the water in test tubes B and C?
Answer
To prevent any loss of water by evaporation from the surface.
Question
What is the conclusion from test tube D in the root absorption experiment, where the leaves shrivelled?
Answer
The leaves lost water by evaporation (transpiration) that could not be replaced by absorption through the roots.
Question
During photosynthesis, plants produce glucose, which is stored in the form of _____.
Answer
starch
Question
The food stored as starch is transported in the form of _____ solution through the phloem.
Answer
sucrose
Question
What is the term for the transport of dissolved foods (solutes) through the phloem?
Answer
Translocation.
Question
Unlike xylem, phloem is a living tissue, and its cells are called _____.
Answer
sieve tubes
Question
What is a root-hair?
Answer
A long protuberance of an epidermal cell of the root.
Question
Which part of the root-hair is fully permeable, allowing all substances to pass through?
Answer
The cell wall.
Question
Which part of the root-hair is semi-permeable, allowing only water molecules to pass through?
Answer
The inner cell membrane.
Question
What is the first major adaptation of root-hairs for absorbing water?
Answer
The numerous root-hairs provide a very large surface area for greater absorption.
Question
What is the second major adaptation of root-hairs for absorbing water?
Answer
They contain cell sap which is of a higher concentration than the surrounding soil water.
Question
What is the third major adaptation of root-hairs for absorbing water?
Answer
The cell wall is fully permeable, while the cell membrane is semi-permeable.
Question
In the experiment with raisins and grapes, what acts as the semi-permeable membrane?
Answer
The skin or peel of the raisins and grapes.
Question
Define Diffusion.
Answer
The movement of molecules—gas, liquid or solid—from a region of higher concentration to a lower concentration.
Question
Define Osmosis.
Answer
The movement of water molecules from its region of higher concentration through a semi-permeable membrane to its region of lower concentration.
Question
Define Active Transport.
Answer
The movement of molecules from a level of lower concentration to a level of higher concentration, which requires energy.
Question
The upward movement of water and minerals from the roots to the stem and leaves is called _____.
Answer
ascent of sap
Question
Define Root Pressure.
Answer
The pressure developed in the root due to the continuous inflow of water, which helps in pushing the plant sap upwards.
Question
Define Transpiration.
Answer
The loss of water in the form of water vapour from the aerial parts of a plant.
Question
What is the name of the force, caused by the tendency of water molecules to remain joined, that helps pull water up tall trees?
Answer
Cohesion (part of the transpiration pull).
Question
How does sunlight affect the rate of transpiration?
Answer
During daytime, stomata remain open to allow diffusion of carbon dioxide for photosynthesis, which also increases the rate of transpiration.
Question
How does temperature affect the rate of transpiration?
Answer
Transpiration is faster on hot summer days as compared to cold winters.
Question
How does wind affect the rate of transpiration?
Answer
Transpiration is more when the wind is blowing faster as water evaporates faster from the leaves.
Question
How does humidity affect the rate of transpiration?
Answer
Transpiration is reduced if the air is humid, as humid air is already laden with moisture and cannot hold any more.
Question
What is the cooling effect, one of the importances of transpiration?
Answer
Water gets evaporated from the plant surface, and the latent heat required for this evaporation is taken from the plant itself, which cools it.
Question
How does transpiration help in maintaining the concentration of the sap inside the plant body?
Answer
The roots continue to absorb water, and if excess water is not evaporated, the sap would become dilute, preventing further absorption of water with minerals.
Question
What are the three main uses of the water absorbed by plant roots?
Answer
Transportation, food production, and cooling.
Question
Nutrient elements required in larger concentrations by plants are known as _____.
Answer
macro-nutrients
Question
Nutrient elements required in very small amounts by plants are known as _____.
Answer
micro-nutrients
Question
What is the role of Nitrogen (N) in a plant?
Answer
It is a major constituent of all proteins.
Question
What are the major deficiency symptoms of Nitrogen (N) in a plant?
Answer
Yellowing of leaves and wrinkling of cereal grains.
Question
What is the role of Phosphorus (P) in a plant?
Answer
It is a constituent of the cell membrane and certain proteins.
Question
What are the major deficiency symptoms of Phosphorus (P) in a plant?
Answer
Purple and red spots on leaves, and delay in seed germination.
Question
What is the role of Potassium (K) in a plant?
Answer
It is more abundant in growing tissues and is involved in the opening and closing of stomata.
Question
What is a major deficiency symptom of Potassium (K) in a plant?
Answer
Poor growth.
Question
What is the role of Iron (Fe) in a plant?
Answer
It is a constituent of some proteins.
Question
What is a major deficiency symptom of Iron (Fe) in a plant?
Answer
Yellowing of leaves.
Question
What is the role of Manganese (Mn) in a plant?
Answer
It is a constituent of some enzymes.
Question
What are the major deficiency symptoms of Manganese (Mn) in a plant?
Answer
Yellowing of leaves, with grey spots.
Question
What is the role of Zinc (Zn) in a plant?
Answer
It is a constituent of plant hormones and activates enzymes.
Question
What are the major deficiency symptoms of Zinc (Zn) in a plant?
Answer
Deshaped leaves, yellowing of leaves, and stunted plant growth.
Question
Which of the two vascular tissues, xylem or phloem, is primarily composed of dead cells?
Answer
Xylem.
Question
What two forces, other than root pressure, contribute to the ascent of sap?
Answer
Capillary force and transpiration pull (cohesion).
Question
What would you observe if an experiment demonstrating transpiration (plant in a polythene bag) was placed in a dark room?
Answer
No drops of water would appear on the inside of the bag.