Frank Brothers Solutions for ICSE Class 10 Biology Chapter 5 Transpiration

Solution 1:

Answer:

1. Transpiration: It is the loss of water in the form of water vapour from aerial parts of the plant.
2. During transpiration, water comes out in the form of water vapour.
3. Transpiration takes place in leaves through stomata. Stomata consist of guard cells, epidermal cells, chloroplast and nucleus.
4. The important difference between transpiration and evaporation is that transpiration is the loss of water from the aerial parts of the plant while evaporation is loss of water from any surface.
5. Stomatal transpiration occurs mainly during the day time when the guard cells of stoma are fully turgid and the stomata are fully open.
6. Cuticular transpiration occurs through the cuticle which is present on the epidermis of leaves & herbaceous stem.
7. Rate of transpiration slows down at night because photosynthesis does not take place and the stomata remains closed.
8. There is a direct effect of temperature on transpiration as the increase in temperature results in increase in the rate of transpiration.
9. When the atmospheric pressure is higher, less water vapour is lost and the rate of transpiration lowers.
10. The relationship between transpiration water and water absorbed from the soil is that if the soil is deficient in water then the rate of water absorption decreases which hence decreases the rate of transpiration and if the soil has excessive water then the rate of water absorption increases which in turn increases the rate of transpiration.

In simple words: Transpiration is like plants sweating. They lose water through tiny holes in leaves. This happens more in hot, windy weather and less at night when the holes close.

📝 Teacher's Note: Tell students to think of transpiration like humans sweating on a hot day. Plants also "sweat" to cool down. Show them a leaf and point to stomata as tiny holes.

🎯 Exam Tip: Always write that transpiration happens through stomata during daytime. Write that it helps cool the plant and transport water up from roots.

Solution 2:

Answer: Experiment to show that during transpiration, evaporation of water takes place in vapour form:

• Take a well watered potted plant.
• Cover the potted plant in a polythene sheet.
• Keep the potted plant in the sunlight.
• Droplets of water are seen on the inner side of the polythene. This shows that the water evaporates and condenses to form droplets of water.

[Diagram: This diagram shows a potted plant covered with a polythene bag. Water droplets are visible on the inside of the bag, proving that water vapour comes out from the plant leaves.]

In simple words: We cover a plant with a plastic bag. Water droplets form inside the bag. This proves plants give out water vapour just like our breath on a cold day.

📝 Teacher's Note: Do this experiment in class with students. They can see the water droplets forming. It's like covering your mouth with a plastic bag and seeing your breath.

🎯 Exam Tip: Draw the diagram clearly. Label the polythene bag and water droplets. Write that sunlight is needed for this experiment to work.

Solution 3:

Answer: There are three types of transpiration found in plants:

1. Cuticular transpiration
2. Lenticular transpiration
3. Stomatal transpiration

In simple words: Plants lose water in three ways - through the waxy coating on leaves, through tiny holes in stems, and through the main holes in leaves called stomata.

📝 Teacher's Note: Explain that stomatal is the main type. Show students that cuticle is like the waxy coating on an apple. Lenticels are like tiny breathing holes in tree bark.

🎯 Exam Tip: Remember all three names correctly. Write that stomatal transpiration is the most important one. It happens most during daytime.

Solution 4:

Answer: The transpiration occurs highest during the day time as with the increase in light intensity the rate of transpiration increases.
In simple words: Plants lose most water during bright sunlight hours. More light means more transpiration, just like we sweat more in hot sun.

📝 Teacher's Note: Ask students when they sweat most - in sun or shade? Same way, plants lose more water in bright sunlight. At night, the holes close and less water is lost.

🎯 Exam Tip: Write "day time" and "light intensity increases". Also mention that stomata open more in light, so more water escapes.

Solution 5:

Answer: The difference between transpiration and evaporation are as follows:

In simple words: Transpiration happens only in living plants through special holes. Evaporation happens from any wet surface like a puddle or wet clothes.

📝 Teacher's Note: Show students a wet cloth drying in sun (evaporation) and a plant losing water (transpiration). Both lose water but only plants can control the process.

🎯 Exam Tip: Write that transpiration needs living cells and stomata. Evaporation happens from any surface. Transpiration is controlled, evaporation is not controlled.

Solution 6:

Answer: The difference between transpiration and guttation are as follows:

In simple words: Transpiration gives out water vapour during day through stomata. Guttation gives out liquid water drops at night through special pores called hydathodes.

📝 Teacher's Note: Show students morning dew drops on grass tips - that's guttation, not dew. Transpiration is invisible water vapour, guttation is visible water drops.

🎯 Exam Tip: Remember: Transpiration = vapour + day + stomata. Guttation = liquid drops + night + hydathodes. Don't confuse the two processes.

Solution 7:

Answer: The three means of water loss in plants are:

1. Respiration
2. Guttation
3. Bleeding

In simple words: Plants lose water in three ways - through breathing (respiration), through water drops at leaf tips (guttation), and through cut wounds (bleeding).

📝 Teacher's Note: Explain that bleeding happens when we cut a plant stem and water comes out. Like when we get hurt and blood comes out. Show students water drops on grass in morning for guttation.

🎯 Exam Tip: Don't include transpiration in this list. These are the other three ways plants lose water. Write all three names clearly.

Solution 8:

Answer: The opening and closing of stomata depends upon the changes in the turgidity of their guard cells. Due to absorption of water the guard cells become turgid. Their inner walls are pulled apart by their outer wall. The gap between the guard cells become wider and stomata open. When guard cells are flaccid due to loss of water, the outer walls are not stretched, their inner walls are not pulled apart decreasing the gap between the guard cells and stomata close.

[Diagram: This diagram shows two stomata - one open and one closed. The open stoma has swollen guard cells with a wide gap between them. The closed stoma has shrunken guard cells with no gap.]

In simple words: Stomata work like automatic doors. When guard cells fill with water, they swell up and the door opens. When they lose water, they shrink and the door closes.

📝 Teacher's Note: Compare guard cells to balloons. When you blow air (water) into a balloon, it gets bigger. When you let air out, it shrinks. Same thing happens with guard cells.

🎯 Exam Tip: Write "turgid" for swollen cells and "flaccid" for shrunk cells. Draw the diagram showing open and closed stomata clearly.

Solution 9:

Answer: Mechanism of stomata: Stomata are small pores present on the leaves which contains two kidney-shaped guard cells. The opening and closing of stomata depends upon the changes in the turgidity of their guard cells. Due to absorption of water the guard cells become turgid. Their inner walls are pulled apart by their outer wall. The gap between the guard cells become wider and stomata open. When guard cells are flaccid due to loss of water, the outer walls are not stretched, their inner walls are not pulled apart decreasing the gap between the guard cells and stomata close.
In simple words: Stomata are tiny holes with two kidney-shaped guard cells around them. These cells act like doors that open and close based on how much water they have inside.

📝 Teacher's Note: Show students a kidney bean to explain the shape of guard cells. Tell them that these cells are very smart - they know when to open and close automatically.

🎯 Exam Tip: Write "kidney-shaped guard cells" and explain both opening and closing process. Mention that turgid cells open stomata and flaccid cells close stomata.

Solution 10:

Answer: Transpiration is important for plants because it evaporates excess water which produces a cooling effect to plants. This process also helps in ascent of sap and transportation of water and minerals to the various parts of the plants.
In simple words: Transpiration helps plants stay cool like sweating helps us. It also pulls water and food up from roots to all parts of the plant like a water pump.

📝 Teacher's Note: Compare transpiration to air conditioning in our homes. It cools the plant and also acts like a water pump to carry nutrients from soil to leaves.

🎯 Exam Tip: Write three benefits: cooling effect, ascent of sap, and transport of minerals. Always mention that it creates a pull that helps water move up.

Solution 11:

Answer: Transpiration: It is the loss of water in the form of water vapour usually during day time. Following are its importance in plants:

1. It causes transpirational pull which helps in the absorption of water.
2. It produces a cooling effect.
3. It helps in the ascent of sap.

In simple words: Transpiration is like plants breathing out water. It helps them drink more water from soil, stay cool, and move water up to all parts.

📝 Teacher's Note: Explain transpirational pull like drinking through a straw. When you suck from top, liquid moves up from bottom. Same way, transpiration pulls water up from roots.

🎯 Exam Tip: Remember the three main benefits clearly. Write "transpirational pull" - this is the key term examiners look for.

Solution 12:

Answer: The typical structure of stomata: Stomata are minute pores of elliptical shape surrounded by two specialized epidermal cells called guard cells. These guard cells are kidney shaped which control the opening and closing of stomata. It also consists of nucleus, stoma, epidermis and chloroplast.

[Diagram: This diagram shows the detailed structure of stomata with labeled parts - lower epidermis, guard cell, stomatal pore, inner wall, nucleus, and chloroplast. It also shows H2O exit and entry in open and closed positions.]

In simple words: Stomata are tiny oval holes surrounded by two kidney-shaped cells called guard cells. These cells have all the parts normal plant cells have - nucleus and chloroplast.

📝 Teacher's Note: Draw a simple diagram on the board. Show students that guard cells are special because they can change shape to open and close the hole between them.

🎯 Exam Tip: Draw and label the diagram clearly. Write "kidney-shaped guard cells" and "elliptical pore". Mention all parts - nucleus, chloroplast, epidermis.

Solution 13:

Answer: Following are the importance of transpiration:

1. It causes transpirational pull which helps in the absorption of water.
2. It produces a cooling effect.
3. It helps in the ascent of sap.

In simple words: Transpiration does three important jobs - it helps plants drink water from soil, keeps them cool, and moves water with nutrients up to leaves.

📝 Teacher's Note: Use the analogy of drinking juice through a straw. When you suck from the top, juice moves up from bottom. Transpiration creates this sucking force in plants.

🎯 Exam Tip: List all three points clearly. The most important one is transpirational pull - this helps water move up against gravity from roots to leaves.

Solution 14:

Answer: (i) Hydathodes: Hydathodes are special tissues present tip and margins of leaves. It performs an important function called guttation in which loss of water occur in the form or droplets. These hydathodes allow exudation of water form uninjured plant.

[Diagram: This diagram shows hydathodes as small pores at the leaf margins where water droplets can be seen.]

(ii) Guttation: It is the loss of water in the form of droplets through hydathodes. It generally occurs at night when transpiration has stopped and the rate of absorption is high. This condition cause maximum pressure on roots which forces the water upwards in the form of drops.

[Diagram: This diagram shows water droplets forming on leaf edges, demonstrating the guttation process.]

In simple words: Hydathodes are special holes at leaf edges. At night, when stomata close, water still needs to come out. So it comes out as drops through hydathodes. This is called guttation.

📝 Teacher's Note: Show students morning dew on grass tips. Explain that this is not dew from air, but water pushed out by the plant itself through hydathodes.

🎯 Exam Tip: Write that hydathodes are at leaf tips and margins. Guttation happens at night when transpiration stops. Water comes out as liquid drops, not vapour.

Solution 15:

Answer:

1. A windy day: On a windy day the water vapour released from the leaves by transpiration is removed faster and the leaf does not get saturated with water. So, transpiration is more during a windy day.
2. A foggy day: On a foggy day the area outside the leaf is saturated with water. So, water vapour from the leaves is removed very slowly thereby reducing transpiration.

In simple words: On windy days, the breeze blows away water vapour quickly, so plants lose more water. On foggy days, the air is already full of water, so plants cannot lose much water.

📝 Teacher's Note: Compare this to drying wet clothes. Clothes dry faster on windy days and slower on humid days. Same thing happens with plants and transpiration.

🎯 Exam Tip: Write that wind increases transpiration and fog decreases transpiration. Explain the reason - wind removes vapour quickly, fog saturates the air.

Solution 16:

Answer: Transpiration increases the rate of water absorption because it causes the concentration of sap to rise. In this condition cells absorb water from their neighbours, leaf, stem and root which creates transpirational pull which finally helps in the absorption of water.
In simple words: When plants lose water through transpiration, they become thirsty. This creates a pulling force that sucks up more water from the soil through roots, just like sucking through a straw.

📝 Teacher's Note: Demonstrate with a straw and colored water. When you suck from top, water moves up from bottom. Transpiration creates this suction in plants.

🎯 Exam Tip: Write "transpirational pull" as the key term. Explain that losing water from leaves creates suction that pulls water up from roots through the stem.

Solution 17:
Answer:

1. Potometer
2. Potometer is used to measure the rate of transpiration.
3. The rate of movement of the air bubble will indicate the rate of transpiration.
4. The reservoir is used to provide water to the potometer.

In simple words: A potometer is like a water meter for plants. It shows how much water the plant loses through its leaves.

📝 Teacher's Note: Show students a simple tube with water and explain how the air bubble moves when the plant drinks water. This makes the concept very clear to see.

🎯 Exam Tip: Always write "measures rate of transpiration" and mention the air bubble movement. These are the key points examiners look for.

Solution 18:
Answer:

1. Movement of the air bubble will be decreased or slow.
   Reason: During dark, stomata remains closed due to which the rate of transpiration decreases which hence decreases the movement of air bubble.
2. Movement of the air bubble will be faster.
   Reason: During sunlight, stomata remains opened due to which the rate of transpiration increases which hence increases the movement of air bubble.
3. Movement of the air bubble will be faster.
   Reason: Moving air produces dry air which increases the rate of transpiration which hence increases the movement of air bubble.

In simple words: At night, plant pores close so less water comes out. In sunlight and windy weather, pores open wide so more water comes out.

📝 Teacher's Note: Compare stomata to our mouth - we close it when sleeping, open it when active. Wind makes us lose water faster, same for plants.

🎯 Exam Tip: Always mention stomata opening/closing and connect it to transpiration rate. Write the reason clearly for each condition.

Solution 19:
Answer:

1. The level of mercury in the glass tube will rise.
2. Transpiration
3. Transpiration is the loss of water in the form of water vapour usually during day time.
4. The three advantages of transpiration to the plant are:
   • It causes transpirational pull which helps in the absorption of water.
   • It produces a cooling effect.
   • It helps in the ascent of sap.
5. xylem

In simple words: Transpiration is like plants sweating. It helps them drink water, stay cool, and move nutrients up from roots to leaves.

📝 Teacher's Note: Tell students transpiration is like sweating - it cools us down and plants too. The mercury rises because plant pulls water up like a straw.

🎯 Exam Tip: Write all three advantages clearly. Always mention "cooling effect" and "transpirational pull" - these are key exam terms.

Solution 20:
Answer: A well-watered potted plant shows wilting of leaves on a hot sunny day. As during hot sunny day rate of transpiration is more than the rate of absorption of water.
In simple words: Even though the plant has enough water in the pot, it cannot drink water fast enough on a very hot day. So its leaves become droopy.

📝 Teacher's Note: Show students how we feel thirsty even after drinking water on hot days. Same thing happens to plants - they lose water faster than they can take it.

🎯 Exam Tip: Write "rate of transpiration is more than rate of absorption" - this exact phrase gets you marks. Always compare the two rates.

Solution 21:
Answer: Xylem tissue
In simple words: Xylem is like water pipes in plants. It carries water from roots to all parts of the plant.

📝 Teacher's Note: Compare xylem to water pipes in our house - they carry water to different rooms. Same way, xylem carries water to different plant parts.

🎯 Exam Tip: Just write "xylem tissue" clearly. This is the main water transport tissue in plants.

Solution 22:
Answer:

(ii) Guttation and bleeding

(iii) Cuticular transpiration and lenticular transpiration

(iv) Stomata and lenticels

In simple words: These are different ways plants lose water. Think of them as different types of doors and windows in a house.

📝 Teacher's Note: Use real examples - transpiration is like sweating, evaporation is like water drying from a plate. Guttation is water drops on grass in morning.

🎯 Exam Tip: Make clear tables showing differences. Write key words like "living cells" for transpiration and "physical process" for evaporation.

Solution 23:
Answer: Stomata. Their main functions include exchange of gases and transpiration.
In simple words: Stomata are tiny holes on leaves. They let air in and out, and also let water vapor escape from the plant.

📝 Teacher's Note: Show students leaf under magnifying glass to see tiny holes. Explain stomata are like nose holes - they help the plant breathe.

🎯 Exam Tip: Always mention both functions - gas exchange AND transpiration. These are the two main jobs of stomata.

Solution 24:
Answer: Transpiration
In simple words: This is the process where plants lose water through their leaves as water vapor.

📝 Teacher's Note: Tell students it is like plants sweating to stay cool. The water comes out as invisible vapor, not liquid drops.

🎯 Exam Tip: Write the word clearly. Make sure you know the definition - loss of water as vapor from aerial parts of plants.

Solution 25:
Answer: Potometer: It is an apparatus where the rate of the air bubble will indicate the rate of transpiration. It is used to measure the rate of transpiration.
In simple words: A potometer is like a plant thermometer. It shows how fast a plant is losing water by watching an air bubble move.

📝 Teacher's Note: Draw a simple tube with water and air bubble. Show students how bubble moves when plant drinks water. This visual helps a lot.

🎯 Exam Tip: Mention both - "measures rate of transpiration" and "air bubble movement indicates rate". Both points are important for full marks.

Solution 26:
Answer: The three factors that enhance the rate of transpiration are:

1. High intensity of light
2. High temperature
3. Low humidity

In simple words: Plants lose water faster when it is very bright, very hot, or when air is very dry. Like we sweat more on hot sunny days.

📝 Teacher's Note: Relate to students' experience - we lose more water on hot, bright, dry days. Same for plants. Use examples like desert vs rainy day.

🎯 Exam Tip: Write all three factors clearly. Use exact words - "high intensity", "high temperature", "low humidity". These are standard exam terms.

Solution 27:
Answer: Plants absorb more water than what is required. Out of 100%, only 5% of the water is used in metabolic reactions while the remaining 95% is released into the atmosphere as transpiration. The three uses of this phenomenon are:

1. It helps in transportation of water and minerals to the various parts of the plant.
2. It produces a cooling effect to the plants.
3. It evaporates excess water.

In simple words: Plants drink much more water than they need. They use only 5% and throw away 95%. This waste water helps them get nutrients, stay cool, and get rid of extra water.

📝 Teacher's Note: Tell students it is like drinking lots of water on hot day - we use some and sweat out the rest to stay cool. Plants do the same thing.

🎯 Exam Tip: Remember the numbers - 5% used, 95% lost. Write all three benefits clearly. Cooling effect is a very important point to mention.

Solution 28:
Answer:

1. False
2. Cobalt chloride \( (CoCl_2) \) paper

In simple words: We use special blue paper that turns pink when it touches water. This shows us where water is coming out from the plant.

📝 Teacher's Note: Bring cobalt chloride paper to class if possible. Show students how it changes color. This chemical test makes transpiration visible.

🎯 Exam Tip: Remember cobalt chloride paper changes from blue to pink when water is present. This is the standard test for detecting water vapor.

Solution 29:
Answer: An experiment to prove that transpiration occurs more from the lower surface of a leaf:

• Take a potted plant.
• Place two Cobalt chloride papers on either side of a leaf of the potted plant with the help of two glass slides.
• Keep the plant in sunlight.
• After sometime it is observed that the cobalt chloride paper on the lower side of the leaf changed its colour to pinkish than the upper side. This shows that rate of transpiration is more on the lower surface of a leaf.

[Diagram: This diagram shows a potted plant with a leaf held between two glass slides with cobalt chloride paper on both sides. The lower diagram shows the cross-section view of how the papers are placed on both surfaces of the leaf.]

In simple words: We put special blue papers on top and bottom of a leaf. The bottom paper turns pink faster, showing more water comes out from the bottom of leaves.

📝 Teacher's Note: Explain that most stomata are on the bottom of leaves, like having more doors on the ground floor. That is why more water escapes from there.

🎯 Exam Tip: Mention the color change clearly - blue to pinkish. Write that lower surface shows more color change. This proves the point.

Solution 30:
Answer: Potometer is the instrument used for measuring the rate of transpiration.
In simple words: A potometer is like a speedometer for plants. It tells us how fast the plant is losing water.

📝 Teacher's Note: Compare it to measuring speed of a car. The potometer measures speed of water loss from plants.

🎯 Exam Tip: Write "instrument used for measuring rate of transpiration" clearly. This is the standard definition.

Solution 31:
Answer: Cobalt chloride paper.
In simple words: This is special paper that changes color when it touches water. It helps us see transpiration happening.

📝 Teacher's Note: Show students how this paper works like a water detector. Blue color means dry, pink color means water is there.

🎯 Exam Tip: Remember the chemical name clearly - cobalt chloride paper. This is the standard test material for detecting water vapor.

Solution 32:
Answer: False
In simple words: The given statement is not correct.

📝 Teacher's Note: Make sure students read the question carefully to understand what statement they are evaluating.

🎯 Exam Tip: Write "False" clearly. Read true/false questions very carefully before answering.

Solution 33:
Answer: Loss of water as droplets through leaves of an intact plant is termed guttation.
In simple words: Guttation is when plants push out water drops from their leaves. You can see these drops on grass early in the morning.

📝 Teacher's Note: Show students water drops on plants early morning. Explain this is not dew but water pushed out by the plant itself.

🎯 Exam Tip: Write "loss of water as droplets" and "guttation" clearly. Remember it happens through special pores called hydathodes.

Solution 34:
Answer: The three adaptations found in plants to reduce transpiration are:

1. Sunken stomata
2. Modification of leaves into spines
3. Presence of thick cuticle

In simple words: Desert plants have special tricks to save water. They hide their pores, turn leaves into thorns, and have thick waxy coating.

📝 Teacher's Note: Show pictures of cactus and desert plants. Point out thorns (modified leaves), waxy surface (cuticle), and explain sunken stomata like hidden doors.

🎯 Exam Tip: Remember these three main adaptations. Use examples like cactus to explain each adaptation clearly.

Solution 35:
Answer:

1. The aim of the experiment is to demonstrate transpiration.
2. To prevent the evaporation of water from the surface.
3. The level of water in test tube (a) will decrease.
4. The fall in the water level in the test tube (a) is because of transpiration through aerial parts of the plant.
5. Test tube (b) has been taken as a control experiment. Since no transpiration takes place without the plant.

In simple words: This experiment shows that plants drink water. Tube with plant has less water because plant used it. Tube without plant stays same.

📝 Teacher's Note: Explain control experiment concept - we need one tube with plant and one without to prove the plant is causing water loss.

🎯 Exam Tip: Always mention "control experiment" and explain why it is needed. Write clear difference between test tube (a) and (b).

Solution 36:
Answer:

1. (d) stop growing and gradually die of starvation.
2. (a) open stomata, dry atmosphere and moist soil.

In simple words: Without carbon dioxide, plants cannot make food and will die. Plants transpire most when pores are open, air is dry, and soil has water.

📝 Teacher's Note: Explain that plants need CO2 like we need food. Without it, they starve. Best transpiration needs open pores, dry air, and wet soil.

🎯 Exam Tip: Remember plants need CO2 for photosynthesis to make food. For transpiration, think of best conditions for water loss.

Solution 37:
Answer: Cuticle, lenticels and stomata are the three openings through which transpiration occurs.
In simple words: Plants lose water through three types of openings - waxy surface (cuticle), tiny holes on leaves (stomata), and pores on stems (lenticels).

📝 Teacher's Note: Show students different plant parts - smooth leaf surface (cuticle), tiny holes on leaves (stomata), and bark pores (lenticels).

🎯 Exam Tip: Remember all three types - cuticle, stomata, lenticels. These are the three pathways for transpiration.

Solution 38:
Answer: Hydathodes: Guttation
In simple words: Hydathodes are special pores that push out water drops. This process is called guttation.

📝 Teacher's Note: Tell students hydathodes are like special taps that plants use to push out extra water as drops, not vapor.

🎯 Exam Tip: Remember hydathodes are connected to guttation (water drops), not transpiration (water vapor).

Solution 39:
Answer:

1. The plant was kept in the dark to destarch the leaves.
2. Sodium hydroxide absorbs CO2 thereby making the flask CO2 free.
3. (1) C, (2) E
4. Sunlight

In simple words: The plant was kept in dark to remove stored food. Sodium hydroxide removes CO2 from air. Sunlight is needed for the process to work.

📝 Teacher's Note: Explain that plants store food as starch. Dark period removes this stored food so we can test fresh food making.

🎯 Exam Tip: Remember "destarch" means remove stored starch. Sodium hydroxide absorbs CO2. Sunlight is essential for photosynthesis.

Solution 40:
Answer:

1. To absorb the moisture formed by transpiration.
2. Yes, the weight of CaCl2 vials kept on the lower side will be more because transpiration will be more on the lower surface and the moisture absorbed.
3. To check the outside and inside pressure.
4. Transpiration is the loss of water from the aerial parts of the plant in the form of water vapour.

In simple words: The chemical absorbs water vapor from transpiration. Lower side vials become heavier because more water comes out from bottom of leaves.

📝 Teacher's Note: Explain that CaCl2 is like a sponge for water vapor. It gets heavier when it absorbs moisture from transpiration.

🎯 Exam Tip: Write that lower surface shows more transpiration, so CaCl2 vials there will gain more weight. Always define transpiration clearly.

Solution 41:
Answer:

1. A = Guard cell B = Stomatal aperture
2. Stomata
3. The function of the guard cells are that they help to regulate the rate of transpiration by opening and closing the stomata thus preventing excessive water loss.
4. The two structural features of guard cells are:
   • The guard cells have thin outer wall and thick inner wall.
   • Guard cells contain chloroplast in their cytoplasm.
5. These are present on the lower surface of the dorsiventral leaf.
6. Transpiration is the loss of water in the form of water vapour from aerial parts of the plant.
7. Five

In simple words: Guard cells are like security guards that control stomata doors. They open and close to control water loss from plants.

📝 Teacher's Note: Compare guard cells to doormen who open and close doors. The special wall structure helps them change shape to open/close stomata.

🎯 Exam Tip: Remember guard cells control stomatal opening. Write their structure clearly - thin outer wall, thick inner wall, contain chloroplasts.

Solution 42:
Answer:

1. (b) Root pressure
2. (d) environmental conditions may dry
3. (a) do photosynthesis and synthesis osmotically active
4. (d) Transpiration
5. (d) hydathodes
6. (b) guttation
7. (b) From the lower surface of leaf
8. (a) Potometer
9. (c) 90
10. (d) atmosphere is dry and temperature is high
11. (c) layering the bottom with vaseline
12. (a) approximately 10%
13. (a) suction force
14. (d) all of the above
15. (a) xerophyte
16. (a) Curtis

In simple words: These are multiple choice questions about transpiration, plant structures, and water movement in plants.

📝 Teacher's Note: Go through each answer with students. Explain why each option is correct. Use examples to make concepts clear.

🎯 Exam Tip: Read each question carefully. Remember key terms like potometer, xerophyte, guttation, and root pressure. Practice these MCQs regularly.