Selina Concise Solutions for ICSE Class 8 Biology Chapter 1 Transportation in Plants

REVIEW QUESTIONS

Multiple Choice Questions:

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

(a) Diffusion occurs when molecules move:
1. from lower concentration to higher concentration.
2. from higher concentration to lower concentration through a membrane.
3. from higher concentration to lower concentration.
4. when energy is used.

Answer:
(3) from higher concentration to lower concentration.
This process happens naturally until the molecules are spread out evenly. It is a passive movement that does not require any energy from the plant.
Teacher's Tip: Think of a perfume spray spreading across a room - it moves from where it is strong to where it is weak.
Exam Tip: Remember that diffusion does not strictly require a membrane, unlike osmosis.

(b) Ascent of sap in plants takes place through:
1. Cortex
2. Epidermis
3. Xylem
4. Phloem

Answer:
(3) Xylem
Xylem acts like a system of pipes that carries water and minerals from the roots to the top of the plant. The term "ascent" simply means the upward movement of this liquid.
Teacher's Tip: Remember "X" for Xylem and "W" for Water (X is near W in the alphabet).
Exam Tip: Use the term "unidirectional" to describe xylem flow for extra marks.

(c) If the xylem vessels of a plant are plugged:
1. The leaves will turn yellow
2. No food will be made
3. The plant will wilt (shrivel)
4. The plant will continue to grow

Answer:
(3) The plant will wilt (shrivel)
When xylem is blocked, the plant cannot get the water it needs to stay firm and upright. Without water pressure, the cells collapse and the plant becomes limp.
Teacher's Tip: Think of a garden hose being stepped on; the water stops and the end goes flat.
Exam Tip: Define "wilting" as the loss of turgidity in plant cells.

(d) Force responsible for the ascent of sap is:
1. Capillary force
2. Root pressure
3. Transpirational pull
4. All the three

Answer:
(4) All the three
These three forces work together like a team to pull water against gravity. While transpiration pull is the strongest, capillary action and root pressure help start and maintain the flow.
Teacher's Tip: It is like drinking through a straw; your mouth provides the pull, but the straw's narrowness helps too.
Exam Tip: If asked for the "major" force, always highlight Transpirational Pull.

(e) Raisins swell when put in:
1. Rain water
2. Tap water
3. Mustard oil
4. Saturated sugar solution

Answer:
(1) Rain water
Rain water is pure and has a higher concentration of water than the inside of a raisin. Water moves into the raisin through its skin by the process of osmosis.
Teacher's Tip: Raisins are "thirsty" for pure water because they are so sugary inside.
Exam Tip: Mention that the raisin skin acts as a semi-permeable membrane.

(f) The root-hairs are suited for absorbing water from the soil because:
1. They have a large surface area
2. They have a semi-permeable membrane
3. They contain a solution of higher concentration than the surrounding water.
4. All the three.

Answer:
(4) All the three.
Each of these features makes the root hair a perfect tool for drinking up soil water. The high concentration inside pulls water in, while the large surface area gives more space for water to enter.
Teacher's Tip: Root hairs are like millions of tiny straws spread out to find every drop of water.
Exam Tip: Always list all three reasons if this is a short-answer question.

(g) Transpiration is defined as:
1. the rise of water up to the stem of a plant.
2. the elimination of water with dissolved water products.
3. the loss of water as water vapour from the aerial parts of a plant.
4. the loss of water as water vapour from the roots as well as the leaves of the plant.

Answer:
(3) the loss of water as water vapour from the aerial parts of a plant.
Plants "sweat" out excess water through tiny holes called stomata, mostly on their leaves. This loss of water vapour actually helps the plant stay cool and pull up more water.
Teacher's Tip: Aerial parts mean parts above the ground, like leaves and stems.
Exam Tip: Ensure you use the phrase "water vapour" and not just "water".

(h) Which one of the following favours the fastest transpiration rate ?
1. A cool, humid, windy day,
2. A hot, humid, windy day,
3. A hot, humid, still day,
4. A hot, dry, windy day.

Answer:
(4) A hot, dry, windy day.
Heat increases evaporation, dry air has more room for moisture, and wind carries the vapour away quickly. These conditions create the perfect "pull" for water to leave the plant.
Teacher's Tip: These are the same conditions that make laundry dry fastest on a clothesline!
Exam Tip: Remember that humidity actually slows down transpiration.

Short Answer Questions:

Question 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:
In test tube A the water level falls because the water was absorbed by the plant through its roots dipped in water. Here no water loss occurs due to evaporation from the water surface due to presence of oil.
In test tube B the water level remains unchanged as it does not contain a rooted plant. Due to the presence of oil on surface no water loss occurs due to evaporation.
This experiment proves that roots are actively responsible for taking up water. The oil layer is crucial because it ensures that only the plant can remove the water.
Teacher's Tip: The oil acts as a "lid" that prevents the air from stealing the water.
Exam Tip: Always mention the role of the oil layer in your explanation.

Question 2: How are roots useful to the plants? Give any two points.

Answer:
Roots are useful to the plants in the following way:
1. It absorbs water and minerals from the soil and transport it upward to various parts of a plant.
2. Roots fix the plant firmly in the ground.
Roots serve as both the "anchor" and the "feeding system" for the entire plant. Without them, a plant would neither be able to stand up nor get nutrients to grow.
Teacher's Tip: Think of roots as a combination of a foundation and a set of straws.
Exam Tip: Number your points clearly as 1 and 2 to make it easy for the examiner.

Question 3: What do xylem vessels carry?

Answer:
The xylem vessels carry the water and minerals absorbed by the roots to the stem and leaves.
These vessels form a long, continuous pipeline from the very tip of the roots to the edge of every leaf. This mixture of water and minerals is often called "xylem sap."
Teacher's Tip: Xylem is like the plumbing system of a house, bringing water to every room.
Exam Tip: Don't forget to mention "minerals" along with "water".

Question 4: Name the plant tissue which helps in carrying the food to different parts.

Answer:
Phloem.
Phloem is the living tissue that transports glucose and other nutrients made in the leaves to the rest of the plant. This movement can go both up and down, depending on where the food is needed.
Teacher's Tip: Phloem sounds like "Food" (Ph = F).
Exam Tip: Remember that phloem transport is called "translocation".

Question 5: Define the terms: (a) semi-permeable membrane (b) osmosis.

Answer:
(a) Semi-permeable membrane: It is a membrane that allows the movement of solvent molecules (e.g. water molecules) through it but prevents the movement of solute particles (e.g. sugar or salt molecules).
For example: Egg membrane, parchment membrane, cellophane paper etc. are semi permeable membranes.
(b) Osmosis: The diffusion of water molecules through a semi-permeable membrane from a region where water is more concentrated to a region where it is less concentrated is called osmosis.
In other words, osmosis is the diffusion of water from its pure state or dilute solution into a stronger or concentrated solution through a semi-permeable membrane.
A semi-permeable membrane acts like a filter with very tiny holes. Osmosis is specifically the movement of water across this filter to balance concentrations.
Teacher's Tip: Think of a tea bag; the water goes in and out, but the tea leaves stay inside.
Exam Tip: In the definition of osmosis, you must mention the "semi-permeable membrane".

Question 6: Under what conditions do plant transpire (a) more quickly and (b) most slowly?

Answer:
(a) Transpiration is faster on hot summer days as compared to cold winters.
(b) Transpiration is reduced if the air is humid. Air cannot hold any water molecules when it is already laden with moisture (humidity).
High temperatures give water molecules more energy to turn into vapour. On the other hand, damp air is already "full" of water, so it can't take much more from the plant.
Teacher's Tip: Hot and Dry = High Transpiration. Cold and Humid = Low Transpiration.
Exam Tip: Mention the role of "stomata" opening in sunlight for faster transpiration.

Question 7: Given here 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:
Path of water through the root hair to the xylem vessels.
Water enters the root hair from the soil and travels through the cells of the cortex. Finally, it enters the xylem vessels to be transported upward.
Teacher's Tip: Arrows should point from the outside soil into the center of the root.
Exam Tip: Ensure your arrows are continuous to show a clear path.

Question 8: Why is the structure of the root hair is quite suitable for absorbing water from the soil ?

Answer:
The root hair are suitable for absorbing water from the soil in the following three ways:
1. The root hairs present a large surface area. More the surface area, greater is absorption.
2. The cell wall is of cellulose nature and forms permeable membrane and the plasma membrane around the vacuole forms the semi-permeable membrane.
3. Root hairs have solution (cell sap) of a higher concentration than the surrounding soil water.
These three features work together to maximize water intake. The high internal concentration creates a natural "pull" that brings water in through the large surface area.
Teacher's Tip: It is all about "Area, Membrane, and Concentration"!
Exam Tip: Use the term "cell sap" when describing the internal liquid of the root hair.

Question PQ: In an experimental set-up, a dye was placed at the bottom of a beaker filled with water as shown in figure A, below. After some time, the entire water in the beaker got coloured uniformly as shown in figure D. (a) Name and define the phenomenon shown in the experiment. (b) In all the four figures, two kinds of molecules are shown symbolically - larger and smaller. Which molecules are of the solute and which are of the solvent? (c) If all the dark shaded molecules in A are tightly enclosed in a cell membrane, what will be the nature of movement of the molecules, if any ?

Answer:
(a) Name and define the phenomenon shown in the experiment.
Answer: The phenomenon is diffusion. Diffusion is the movement of the molecules or atoms of a substance (whether in a solid, liquid or gaseous state) from the region of higher concentration to the region of lower concentration.
(b) In all the four figures, two kinds of molecules are shown symbolically - larger and smaller. Which molecules are of the solute and which are of the solvent?
(a) Larger: (b) Smaller:
Answer: (a) The larger molecules are of the solute (dye)
(b) The smaller molecules are of the solvent (water)
(c) If all the dark shaded molecules in A are tightly enclosed in a cell membrane, what will be the nature of movement of the molecules, if any ?
Answer: As the concentration of solvent molecules is more in the left side of the figure A. The cell membrane will act as semi permeable membrane and will allow only the solvent molecules of water to move towards the solute particles. So the solvent molecules will move towards the solute particles. This will show the phenomenon or process of osmosis.
Diffusion is about molecules spreading out freely, while osmosis is about water moving across a barrier to balance things out. In part (c), because the dye is trapped, only the water can move to even out the mixture.
Teacher's Tip: Solute is what you dissolve (dye), Solvent is what does the dissolving (water).
Exam Tip: Be very careful to distinguish between water movement and dye movement in your answers.

Question 9: Briefly explain, how transpiration helps in upward conduction of water in plants? (a) (b)

Answer:
(a) Plants continuously absorb water through their roots. This water is sent up through the stem to all parts of the plant, including the leaves. Only a little amount, of water is retained in the plant or utilised by it in photosynthesis. The rest of it gets evaporated into the atmosphere as water vapour through the stomata present in the epidermis of the leaves and other aerial parts of the plant. This creates a suction pressure which pulls up water from xylem of the roots to the stem and then to the leaves.
(b) Xylem tissues are in the form of capillary tubes (tracheids and fibres) where narrower the diameter, greater will be the force. Whenever the xylem vessels lay empty, such as during the loss of water by transpiration, the water from below rises into them by a capillary force.
During day time, water is lost from the surface of the leaves by the process of transpiration. In this process, more and more water molecules are pulled up due to their tendency of rentainingjoined (cohesion). Such pulling force created by the leaves is very important in the case of tall trees where an upward conduction of water takes place.
Transpiration creates a powerful vacuum-like effect called "transpiration pull." Because water molecules stick together, pulling one at the top pulls the entire chain of water up from the roots.
Teacher's Tip: Think of a chain of people holding hands; if the person at the front moves, everyone is pulled forward.
Exam Tip: Use the word "cohesion" to describe how water molecules stick to each other.

Question 10: How does temperature, light intensity and wind affect transpiration?

Answer:
Temperature: Transpiration is faster on hot summer days as compared to cold winters.
Light intensity: The transpiration rate is increased due to the increase in light intensity. During daytime in the sunlight, the rate of transpiration is faster. This is because the stomata remain open to allow the inward diffusion of carbon dioxide for photosynthesis. During dark, the stomata are closed, and hence transpiration hardly occurs at night.
Wind: Transpiration is more when the wind is blowing faster as water evaporates faster from the leaves.
These environmental factors all speed up the process by helping water turn into vapour or moving it away from the leaf. Sunlight is unique because it also controls the opening of the stomata "doors."
Teacher's Tip: Light = Doors open; Heat & Wind = Faster exit!
Exam Tip: Always explain "why" the factor affects the rate (e.g., wind removes water vapour).

Question 11: The set up shown alongside was kept in sunlight for an hour. It was observed that drops of water appeared on the inside of the polyethylene bag. (a) Name the process which is being demonstrated. (b) Why was the pot and its soil left uncovered by the polythene bag ? (c) Why was the pot left in the sunlight? (d) Suppose the pot in this experiment was placed inside a dark room instead of placing it in sunlight for some time. What difference will be noticed?

Answer:
(a) The process demonstrates the loss of water that has appeared in the polythene bag is transpiration. As the potted plant covered with polythene bag is kept in the sunlight there will be loss of water through the stomata present on the leaves. The water drops will appear inside the polythene bag as a result of loss of water from the stomata. This is due to transpiration.
(b) As the potted plant is kept in the sun. The water vapours will also be given by the pot and the wet soil. These vapours (water drops) will also go inside the polythene if it covers the pot and the soil. We left the pot and soil uncovered by the polythene so that we may find the loss of water from the aerial parts of the plant covered with polythene bag. This shows that the water gets deposited in the polythene bag has come from the aerial parts of plant.
(c) As we keep the pot in the sunlight the stomata will open and the loss of water i.e., transpiration takes place from the aerial parts of the potted plant and the stomata. The loss of water will be more (transpiration) in the sun, and water vapours will appear in the polythene bag very soon.
(d) As we keep the pot inside the room, the stomata will not open fully and the rate of loss of water will be very-very less, and no water vapours will appear in the polythene bag. By keeping the pot in the room the loss of water will be very less and as a result the transpiration will be very less.
This experiment proves that water is released from leaves as vapour, which then condenses into drops. Covering only the branch ensures we know the water came from the leaves, not the soil.
Teacher's Tip: This is the "baggie test" for plant sweat!
Exam Tip: In part (b), emphasize that this is a "control" to ensure accuracy.

Question 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. A semi-permeable membrane allows smaller molecules to pass through, but prevents the larger ones.

(e) Transpiration is the loss of water from the roots of the plant.
Answer: False. Transpiration is the loss of water from the aerial parts of the plant.

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

(g) During transpiration, the leaves lose more water from their upper surface.
Answer: False. During transpiration, the leaves lose more water from their lower surface.
Most of these statements deal with the basic mechanics of how plants drink and breathe. It is important to remember that most stomata are on the bottom of the leaf to prevent too much water loss in direct sun.
Teacher's Tip: Think of stomata as "floor vents" on a leaf.
Exam Tip: When rewriting false statements, underline the corrected part.

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

Answer:
(a) Transportation in plants is carried out by a conducting system.
(b) The upward movement of sap that contains water and minerals is called ascent of sap.
(c) Transpiration is more when the wind is blowing fast.
(d) Most water gets evaporated from the plant from its leaves.
(e) Transpiration is reduced if the air is humid.
(f) The leaves have more stomata on their lower surface.
These terms highlight the key components of the plant's transport network. From the specialized tissue system to the specific pores used for evaporation, each part has a role.
Teacher's Tip: Use the process of elimination for fill-in-the-blanks.
Exam Tip: Double-check that your chosen word makes grammatical sense in the sentence.

Long Answer Questions:

Question 1: Draw a magnified view of the root-hair, and describe, how it helps in the absorption of water from the soil.

Answer:
Give above is a magnified view of a root-hair. It is a long protuberance of a cell. This cell contains a fluid called cell sap which is more concentrated than the surrounding soil water.
The root hair is covered by a very thin ceil membrane that allows water molecules to pass through, but prevents the larger molecules. So the water from the soil passes into the root hairs by osmosis.
The root hair is essentially a single cell that has grown a long "tail" to reach out into the soil. Because it is filled with a salty/sugary sap, it naturally draws in fresh water from the ground.
Teacher's Tip: Label the Cell Wall, Cell Membrane, Cytoplasm, and Nucleus in your drawing.
Exam Tip: Always mention that the cell sap is "more concentrated" than the soil water.

Question PQ: "Raisins swell in water, and grapes shrink in syrup." Explain this phenomenon briefly.

Answer:
When we put some raisins in a bowl containing water, after 10-12 hours, we will notice that the raisins have swelled up. The raisins have absorbed water.
But when we put some soft-skinned grapes in another bowl containing thick syrup of sugar. After 10-12 hours we will notice that grapes have shrunk. The grapes have lost water.
In both cases the gain or loss of water is through the peel acting as a kind of semi permeable membrane. This membrane has very minute pores which allow water molecules to pass through, but prevent the larger ones of sugar.
This is a classic demonstration of osmosis moving water from a "thin" solution to a "thick" one. Water always tries to move to where there is more sugar or salt to balance it out.
Teacher's Tip: Water follows the solute! (Where there's more sugar, water will go).
Exam Tip: Use the terms "Endosmosis" (swelling) and "Exosmosis" (shrinking) for higher marks.

Question 2: How does transpiration help the roots absorb water and minerals from the soil?

Answer:
Transpiration process in plants creates a suction pressure which pulls up water from xylem of the roots to the stem and then to the leaves.
Xylem tissues are in the form of capillary tubes (tracheids and fibres) where narrower the diameter, greater will be the force. Whenever the xylem vessels lay empty, such as during the loss of water by transpiration, the water from below rises into them by a capillary force.
Due to transpirational pull more and more water molecules are pulled up due to their tendency of remaining joined (cohesion). Such pulling force created by the leaves is very important in the case of tall trees where an upward conduction of water takes place.
Think of transpiration as a pump that never stops as long as the sun is shining. By removing water from the top, it creates the space and pressure needed to draw new water from the bottom.
Teacher's Tip: It is like a non-stop elevator for water!
Exam Tip: Mention that this process is essential for very tall trees to get water to their top leaves.

Question 3: Define the three processes by which plants absorb water and minerals from the soil.

Answer:
Following are the tree processes which help the plants to absorb water and minerals from the soil.
1. Diffusion: Soil water moves into the root hairs through the process of diffusion from higher concentration to lower concentration as we put sugar in the milk and the sugar molecules are evenly distributed in the milk and occupy inter molecular spaces of milk.
2. Osmosis: The cell sap and the cell walls act as semi- permeable membranes and permeable membranes. The concentration of the cell sap is more as compared to the water + minerals present in the soil. So the water and dissolved minerals enters the roots by the process of osmosis.
3. Active transport: Root hairs absorb water and minerals from the soil. Water diffuses into the root hairs as the concentration of water is more as compared to root hair.
But in case of minerals these move from lower concentration to molecules of higher concentration. So the minerals from the soil along with water move into the roots. So this is active transport in the opposite direction which needs energy.
While diffusion and osmosis happen "for free," active transport is like an uphill climb that requires the plant to use its own fuel. This is necessary when the plant needs more minerals even if it already has a lot inside.
Teacher's Tip: Diffusion/Osmosis = Downhill (Easy); Active Transport = Uphill (Needs Energy).
Exam Tip: Specifically link "Active Transport" to the absorption of minerals against a concentration gradient.

Question 4: How water absorbed by the roots is important for the plants?

Answer:
The water absorbed by the roots is important for the plant in three main ways:
1. Transportation: The water in the plant body transports substances in solution from one part to another.
2. Food production: Water is used in producing food (photosynthesis) by combining it with carbon-dioxide from the air in the presence of sunlight.
3. Cooling: Water is used to cool the plant by evaporation through leaves when it is hot outside.
Water is the lifeblood of the plant, serving as a delivery vehicle, a raw material for food, and a cooling system. Without constant water absorption, the plant would overheat and starve.
Teacher's Tip: T.F.C. - Transportation, Food, Cooling!
Exam Tip: Mention $H_2O$ as a reactant in the photosynthesis equation.

Question 5: Name the factors which affect the rate of transpiration? State their role in each case.

Answer:
The following are the main factors that affect the rate of transpiration:
1. Sunlight: During daytime, the rate of transpiration is faster. This is because the stomata remain open to allow the inward diffusion ofcarbondioxide for photosynthesis. During dark, the stomata are closed, and hence transpiration hardly occurs at night.
2. Temperature: Transpiration is faster on hot summer days as compared to cold winter.
3. Wind: Transpiration is more when the wind is blowing faster as water evaporates faster from the leaves.
4. Humidity: Transpiration is reduced if the air is humid. Air cannot hold any water molecules when it is already laden with moisture (humidity).
5. Low atmospheric pressure: The rate of transpiration increases when the pressure is low.
Each factor either changes how much water can turn into gas or how easily that gas can leave the plant's surface. Sunlight is the most critical biological factor because it physically opens and closes the stomata.
Teacher's Tip: High Temp, High Wind, High Light = High Transpiration. High Humidity = Low Transpiration.
Exam Tip: Be sure to explain the role of stomata when discussing the Sunlight factor.

Question 6: Mention the two ways in which transpiration helps the plants.

Answer:
Transpiration helps the plants in the following ways:
1. Cooling effect: In transpiration, water gets evaporated from the plant. The heat required for this evaporation is obtained from the plant itself (latent heat) and thus the plant is able to cool itself w'hen it is hot outside.
2. Transpiration helps in maintaining the concentration of the sap inside the plant body: The roots continue to absorb water from the soil. If excess water is not evaporated out, the sap would become dilute, preventing further absorption of water along with the minerals required by the plant.
Transpiration keeps the plant from getting too hot and ensures the internal "soup" of nutrients stays at the right strength. It acts like a regulator for both temperature and nutrition.
Teacher's Tip: It is like the plant's version of sweating and balancing its diet!
Exam Tip: Use the term "latent heat" when explaining the cooling effect.

Question 7: Describe an experiment to show that the plant loses water through its leaves.

Answer:
Experiment: To demonstrate that the plants lose water through its leaves.
• Take one small-sized, well-watered potted plant having a few branches. Place a polythene bag over its one branch as shown in A and tie it with a rubber band.
• Remove all the leaves from another branch (B) of the same plant, cover this too with a polythene bag and tie it with a rubber band.
• Place the plant in sunlight, and observe it after 4-6 hours. You will notice that drops have appeared on the inner surface of the polythene bag over branch A, while no water drops appear on branch B.
• This set-up indicates that most water gets evaporated from the plant through its leaves.
By comparing a leafy branch to a leafless one, we prove that the leaves are the specific exit point for water. The condensation on the plastic proves that the water left the plant as invisible vapour.
Teacher's Tip: This is called a "controlled experiment" because we have a leaf-free branch to compare.
Exam Tip: Draw two simple diagrams showing 'Branch A' (with leaves) and 'Branch B' (without leaves) to support your text.

Question 8: Name any three minerals whose deficiency causes diseases in plants. Give the symptoms of each deficiency.

Answer:
The nutrient elements i.e. minerals are essential for the plants to grow well and complete their life-cycle properly. The minerals are divided into two main categories:
(i) Macro-Nutrients: They are required in larger concentrations and they are obtained from soil.
The three macro-nutrients (minerals) whose deficiency causes diseases in plants are:
1. Nitrogen ($N$) - Yellowing of leaves,wrinkling of cereal grains.
2. Phosphorus ($P$) - Purple and red spots on leaves, delay in seed germination.
3. Potassium ($K$) - Poor Growth
(ii) Micro Nutrients: They are required in small amounts and they are also obtained from soil.
The three micro-nutrients(minerals) whose deficiency causes diseases in plants are:
1. Iron ($Fe$) - Yellowing of Leaves.
2. Manganese ($Mn$) - Yellowing of leaves, with grey spots.
3. Zinc ($Zn$) Desphaped leaves, yellowing of leaves, stunted plant growth.
Plants need a balanced diet just like humans do to stay healthy and strong. If even one of these minerals is missing, the plant will show "sickness" in its leaves and growth patterns.
Teacher's Tip: $N$-$P$-$K$ are the big three minerals you will see on fertilizer bags!
Exam Tip: Be sure to match the correct symptom to the specific mineral.

Question 9: List out the differences between xylem and phloem.

Answer:
The Xylem tissue consists of four types of cells:
1. Tracheids: They are elongated dead cells with tapering ends. Their main function is in upward conduction of water and provide mechanical support.
2. Vessels: They are like tube-like structures placed one above the other forming long channels. They provide mechanical support and also transport water and mineral salts laterally and vertically upward.
3. Fibres: They are long, narrow and tapering at both ends. They provide only mechanical support.
4. Parenchyma: They are living cells and helps in the conduction of water and minerals, and serve for the storage of food.
The Phloem tissue consists of four types of cells:
1. Seive tubes: They are formed of seive cells and form the main conducting part of the phloem. These are cylindrical cells arranged in vertical rows, joined end to end. Their end walls are perforated by pores and are called seive plates. Seive piates helps in passing food material from cell to cell.
2. Companion Cells: They are associated with seive tubes. It help sieve tubes in the conduction of food material.
3. Parenchyma: It is formed of thin-walled unspecialized parenchymatous cells and these cells store food.
4. Phloem fibres: They are dead sclerenchyma fibres formed of elongated cells. These provide mechanical strength.
Xylem is mostly made of dead cells used for pulling water up, while Phloem uses living cells to move food around. Think of Xylem as a plumbing pipe and Phloem as a delivery network.
Teacher's Tip: Xylem = Water (Upward only); Phloem = Food (Both ways).
Exam Tip: If asked to "list differences," create a T-chart for clarity.

ADDITIONAL QUESTIONS

I. Multiple choice questions. Tick (✓) the correct choice:

1. Movement of water in the plant body takes place through
(a) xylem
(b) vascular tissues
(c) phloem
(d) stomata

Answer:
(a) xylem
Xylem is the specific tissue dedicated to moving water from the soil to the leaves. It forms long, continuous tubes that act like drinking straws for the plant.
Teacher's Tip: Remember Xylem carries water, Phloem carries food.
Exam Tip: Don't confuse "vascular tissue" (the group) with "xylem" (the specific water carrier).

2. Prepared food material is carried through
(a) xylem
(b) vascular tissues
(c) phloem
(d) stomata

Answer:
(c) phloem
Phloem carries the sugars made during photosynthesis to parts of the plant that need energy or storage. Unlike xylem, this transport can happen in any direction.
Teacher's Tip: Phloem = Food. Both start with an "F" sound.
Exam Tip: Mention "sugar" or "glucose" as the food being carried.

3. Water from the soil enters the root xylem by the process
(a) diffusion
(b) evaporation
(c) osmosis
(d) transpiration

Answer:
(c) osmosis
Water moves across the semi-permeable membrane of the root cells into the xylem because of the concentration difference. This is a passive process that doesn't require the plant to work.
Teacher's Tip: Osmosis is just diffusion but specifically for water and through a membrane.
Exam Tip: Keywords are "root hair" and "semi-permeable membrane."

4. The loss of water through the stomata of leaves is called
(a) transpiration
(b) wilting
(c) evaporation
(d) osmosis

Answer:
(a) transpiration
Transpiration is essentially "plant sweating" where water vapour exits through tiny leaf pores. This process is vital for keeping the plant cool and pulling more water from the ground.
Teacher's Tip: Transpiration = Plant Perspiration.
Exam Tip: Be careful not to pick "evaporation" as that is a more general physical term.

II. Fill in the blanks:

1. Water passes into a root by the process called osmosis.

2. Osmosis occurs through a partially permeable membrane.

3. Movement of water occurs from a weaker solution into a stronger solution in osmosis.

4. Water is lost from the leaves by transpiration.

5. Upward movement of water takes place through xylem.

Answer:
(Answers are bolded above)
These blanks summarize the core concepts of how plants move materials. Understanding the difference between osmosis (intake) and transpiration (output) is essential.
Teacher's Tip: A "weaker" solution has more water; a "stronger" solution has more solute.
Exam Tip: "Partially permeable" and "semi-permeable" mean the same thing.

III. Which of the following statements are true (T) and which ones are false (F)? Mark T or F:

1. In Spirogyra, transport of materials takes place through osmosis.
Answer: False. In Spirogyra, transport of materials takes place through diffusion.
 

2. Xylem and phloem are vascular tissues.
Answer: True.
 

3. 'Girdling experiment' demonstrates food synthesis in plants.
Answer: False. 'Girdling experiment' demonstrates food transport in plants.

These statements test your knowledge of specific experiments and biological classifications. Remember that girdling specifically blocks the outer phloem layer, stopping food movement.
Teacher's Tip: Spirogyra is simple enough that it only needs basic diffusion.
Exam Tip: When correcting false statements, ensure the new statement is a complete sentence.

IV. Define the following:

1. Osmosis
2. Transpiration
3. Transpiration stream
4. Diffusion

Answer:
1. Osmosis: Osmosis is the process by which water molecules move from a weaker solution into a stronger solution through a partially permeable membrane.
2. Transpiration: Transpiration is the loss of water in vapour form from the leaves into the air.
3. Transpiration stream: The continuous flow of water from roots to the leaves (via xylem vessels) where it evaporates into the air by transpiration is called transpiration stream.
It can be summarised as: Soil -> root hair -> xylem vessels -> leaves -> air.
4. Diffusion: Diffusion is the movement of particles from a high concentration to a low concentration until they are spread out evenly.
These definitions form the vocabulary of plant biology. The "transpiration stream" is the most complex as it describes the entire journey of water through the plant.
Teacher's Tip: Think of the "stream" as a river flowing uphill through the plant.
Exam Tip: For the definition of diffusion, use the phrase "until they are spread out evenly."

V. Describe the function of the following:

1. Xylem
2. Phloem

Answer:
1. Xylem: Xylem transports water and soluble mineral nutrients from the roots up the stem to the leaves.
2. Phloem: Phloem transports dissolved food from the leaves to all other parts of the plant.
Xylem and phloem are the two "highways" inside a plant's body. They ensure that every cell, from the root tip to the flower, gets what it needs to survive.
Teacher's Tip: Upward only for Xylem; Everywhere for Phloem.
Exam Tip: Mention "dissolved food" specifically for phloem function.

VI. Answer the following questions:

Question 1: Name the two aspects of transport in higher plants.

Answer:
The two aspects of transport in higher plants are:
Movement of water and minerals from the roots up to other plant parts through xylem vessels.
Movement of synthesised food from leaves to other plant parts through phloem.
Plants need to transport two different types of supplies: raw materials (water/minerals) and finished products (food). Each has its own dedicated tissue system.
Teacher's Tip: Raw materials go UP; Products go ALL OVER.
Exam Tip: Clearly distinguish between "water/minerals" and "synthesised food."

Question 2: How does transport of materials take place in unicellular plants?

Answer:
Transport of material in unicellular plants takes place by diffusion. The particles move from an area of high concentration to an area of low concentration to attain an equilibrium.
Because these plants are only one cell big, they don't need fancy tubes like xylem. Stuff just naturally moves in and out of the cell to balance things out.
Teacher's Tip: Small size = simple methods!
Exam Tip: Use the word "equilibrium" to describe the final state of diffusion.

Question 3: What are root hair? Mention the function performed by the root hair.

Answer:
Root hair are unicellular hair like structures present behind the root tip. The function of the root hair is to absorb water and mineral salts from the soil by osmosis. They enhance the surface area so that plant can take up water and other nutrients that are further away in the soil.
Root hairs increase the amount of soil a plant can "touch" by a huge amount. This makes them the primary gateway for everything a plant drinks.
Teacher's Tip: They are like the fuzzy bristles on a toothbrush, reaching into small spaces.
Exam Tip: Always mention "increasing surface area" as a primary function.

Question 4: Name the process by which water loss takes place through the leaves.

Answer:
Transpiration.
This process involves water turning into vapour inside the leaf and then drifting out through the stomata. It is a vital part of the global water cycle.
Teacher's Tip: Don't just call it evaporation; in plants, it's transpiration!
Exam Tip: Spelling counts - make sure you get "Transpiration" right.

Question 5: Mention the significance of transpiration.

Answer:
Transpiration is responsible for the continuous upward flow of water from the roots to the leaves. As water is lost from the leaves by transpiration, more is sucked up from the xylem vessels. Thus, it helps in the rise of cell sap by forming transpiration stream.
This process is the "engine" that powers the entire transport system of the plant. Without it, water would sit still in the roots and never reach the thirsty leaves at the top.
Teacher's Tip: No transpiration = No suction = No water at the top!
Exam Tip: Connect transpiration to the "suction pressure" it creates.

Question 6: How does movement and absorption of water take place through the roots?

Answer:
The water is absorbed by the root hair from the soil by osmosis.
Water moves into plant cells by osmosis as follows:
1. The cell membrane of the plant cell is partially permeable.
2. The cell sap inside the vacuole is a strong solution whereas water in the soil is a weak solution.
3. Water moves into the plant cell by osmosis.
4. The concentration of the sap in the vacuole is now weaker.
5. Water passes from the weak solution into the strong solution in the next cell by osmosis.
6. This continues until water reaches the root xylem.
7. From the root xylem, it is pulled up in the stem and leaves through transpiration.
Water moves cell-by-cell across the root like a bucket brigade. It is always moving toward the "stronger" (saltier) solution until it hits the xylem "highway."
Teacher's Tip: Think of it as water chasing the salt across a series of rooms.
Exam Tip: Be sure to describe the step-by-step movement through the cells.

Question 7: Differentiate between osmosis and transpiration.

Answer:
Osmosis is the process by which water molecules move from a weaker solution into a stronger solution through a partially permeable membrane. It occurs between cells.
Transpiration is the loss of water in vapour form from the leaves into air. It occurs when water is released into air.
Osmosis is about water moving *into* or *between* cells, while transpiration is about water *leaving* the plant entirely. One is a liquid movement, the other is a change from liquid to gas.
Teacher's Tip: Osmosis is "Drinking"; Transpiration is "Sweating."
Exam Tip: Mention the "semi-permeable membrane" for osmosis to get full marks.

Question 8: Find the odd one out and give reasons. Root hair, xylem, root, phloem

Answer:
Phloem.
Reason: Root hair, root and xylem are involved in the absorption and movement of water in a plant whereas phloem transports the food in a plant.
While all the others are part of the water-moving system, phloem is the outlier that handles the food. It's the only one in the list not directly linked to the "ascent of sap."
Teacher's Tip: Group the ones that do the same job first to find the odd one.
Exam Tip: Always give a logical scientific "Reason" after picking the odd one.

Question 9: How does transpiration help in the uptake of water from the soil?

Answer:
Transpiration is the loss of water in vapour form from the leaves into the air. As water is used up or lost from the leaves, more is sucked up from the xylem vessels. It's like sucking water up a straw. So there is a continuous flow of water from the roots to the leaves. This movement of water up the xylem is called the transpiration stream.
This constant "sucking" action at the leaves reaches all the way down to the roots. It ensures that as soon as a drop of water is lost at the top, a new drop is absorbed at the bottom.
Teacher's Tip: Just like a juice box - you pull at the top, and the juice moves from the bottom!
Exam Tip: Use the "straw analogy" to make your answer more descriptive.

Question 10: Crossword Puzzle

Answer:
ACROSS
1. Phloem
3. Xylem
4. Blood
5. Transpiration
9. Heart
10. Veins
DOWN
2. Haemoglobin
6. Arteries
7. Platelets
8. Osmosis
This puzzle combines plant transport systems with animal circulatory systems. It shows that both plants and animals need specialized ways to move materials through their large bodies.
Teacher's Tip: Notice how plants use tissues (xylem/phloem) while animals use organs (heart) and fluids (blood).
Exam Tip: Be sure you can define every word found in this crossword.

Question 11: Why is there a need for a transport system in plants and animals?

Answer:
In multicellular plants and animals, a simple process of diffusion cannot move enough oxygen, water, food, waste products with sufficient speed in enough quantity. So, circulatory system in animals and conducting tissues in plants have been developed.
Larger organisms have millions of cells that are far away from the outside world. A specialized "delivery and waste" system is needed to reach every single one of those deep cells quickly.
Teacher's Tip: A big city needs roads; a big organism needs a transport system!
Exam Tip: Mention "multicellular organisms" to show why size matters.

Question 12: What does vascular tissue or conducting tissue comprise of?

Answer:
In plants, the transport of materials takes place by conducting tissues which comprise of special tubes called xylem and phloem.
These tissues together form the "veins" you see in leaves and the woody parts of stems. They are the primary structures for all long-distance movement in the plant.
Teacher's Tip: Vascular = Vessels (Tubes).
Exam Tip: If asked what they comprise of, naming "Xylem and Phloem" is the standard answer.

Question 13: What is sap?

Answer:
Circulation in plants is carried by a liquid called sap. Like blood in animals, it delivers useful substances to plant parts and carries away harmful waste materials. Movement of sap occurs through xylem and phloem elements.
Sap is basically a nutrient-rich watery soup that flows through the plant's tubes. It carries minerals up in the xylem and sugar all around in the phloem.
Teacher's Tip: Sap is to a plant what blood is to a human.
Exam Tip: Mention that sap moves through both xylem and phloem.

Question 14: Give two major functions of roots.

Answer:
1. Roots fix the plant to the soil.
2. Roots absorb water and mineral salts from the soil.
Anchorage (fixing) ensures the plant doesn't blow away, while absorption ensures it has the raw materials to live. These are the two non-negotiable jobs of any root system.
Teacher's Tip: Anchorage and Absorption - the two 'A's of roots!
Exam Tip: Use the word "anchorage" instead of "fix" for a more scientific tone.

Question 15: With the help of a diagram, explain osmosis in plant cells.

Answer:
Water moves into plant cells by osmosis as follows:
1. The cell membrane of the plant cell is a partially permeable membrane.
2. The cell sap inside the vacuole is a strong solution.
3. Water passes into the plant cell by osmosis.
4. The concentration of the sap in the vacuole is now weaker.
5. Water passes from the weak solution into the strong solution in the next cell by osmosis.
This chain reaction moves water from cell to cell across the plant tissue. Each cell acts as a tiny pump, drawing water from its neighbor until it reaches the xylem.
Teacher's Tip: The vacuole is like a storage tank that pulls in the water.
Exam Tip: Be sure your diagram shows the direction of water flow with arrows.

Question 16: Which experiment demonstrates the transport of food material in plants by phloem?

Answer:
Girdling experiment: Girdling of stem removes phloem tissue and the downward and upward movement of food gets blocked. So the stem portion shows swelling in the area due to accumulation of food material.
By removing a ring of bark (which contains the phloem), we stop the food from moving past that point. The resulting bulge above the ring proves that food was trying to travel down but got stuck.
Teacher's Tip: Girdling is also called "Ringing" the tree.
Exam Tip: Explain that the swelling occurs *above* the ring because food comes from the leaves.

Question 17: Why do raisins (dried grapes) swell when kept soaked in water?

Answer:
The raisins contain a concentrated sap and therefore water molecules from the outside move in through partially permeable membrane of the raisins by osmosis and raisins swell.
Because the raisin has lost its water, it is very "salty/sugary" inside compared to plain water. Pure water rushes in to balance this out, filling up the raisin like a balloon.
Teacher's Tip: This is specifically called "Endosmosis" because water goes IN.
Exam Tip: Mention the "partially permeable membrane" to explain why only water moves.