Transport In Plants Question and Answers

Biology Class 11 WBCHSE Transport In Plants Question and Answers

Question 1. Why is simple diffusion called passive transport?
Answer: In simple diffusion, solid, liquid, and gaseous ions or molecules are transported from their region of higher concentration to their region of lower concentration, without requiring any metabolic energy. So, simple diffusion is a type of passive transport.

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Question 2. (1) What is porin? or (2) What is the composition of water channels?
Answer:

1. Porin is a type of protein that makes large pores in the outer membrane of plastids, mitochondria, and some bacteria for the transportation of large molecules across the membrane.
2. Water channels or aquaporins are composed of six transmembrane alpha-helices arranged in a right-handed bundle.

Question 3. In which physiological process of plants, osmotic balance is maintained?
Answer: Osmotic balance in plants is maintained by the process of transpiration.

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Question 4. (1) What is tyw’? or (2) What is the value of tj/w of pure water?
Answer:

1. Refers to water potential.
2. At standard temperature and pressure, pure water is zero.

Question 5. (1) Why water potential of any solvent is
negative? or (2) What is the measuring unit of ψ_w?
Answer:

1. The water potential of pure water is highest, i.e., zero. When a solute is added to it, its water potential decreases. So, the magnitude of the water potential of a solution is always negative.
2. The measuring unit of water potential (ÿw) is Pascal (Pa) Megapascal (MPa) or Kilopascal (kPa).

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Question 6. Two solutions A and B are separated by a permeable membrane. Ψ_w of A is -2.0 kPa and that of B is -1.0 kPa.

1. Whose Ψ_w is more?
2. Diffusion of solution will occur in which direction?

Answer:

1. Ψ_w of solution B is more.
2. Water diffuses from regions of higher water potential to lower water potential. So, the direction of diffusion should be from B to A.

transport question

Question 7. (1) What will be present between the cell wall and the shrunk protoplast of a plasmolysed cell? or (2) What will happen when such a cell is kept in pure water?
Answer:

1. The outer hypertonic solution is present between the cell wall and the shrunk protoplast of a plasmolyzed cell.
2. When a plasmolyzed cell is kept in pure water, deplasmolysis will occur. It means water will diffuse into the cell, protoplast will regain its normal shape. The volume of the vacuole will also increase.

Question 8. (1) What is turgor pressure? or (2) What will be of a fully turgid cell?
Answer:

1. When a plant cell is kept in a hypotonic solution, water enters the cell by endosmosis. This increases the turgidity of the cell. In such a case, the hydrostatic pressure exerted by the protoplast on the cell wall is called turgor pressure.
2. Refers to pressure potential. Water does not enter a fully turgid cell. So, will be zero.

Question 9. Why fishes are salted for preservation?
Answer:

Fishes are salted for preservation because common salt creates a hypertonic solution around the fish. Pathogenic bacteria, fungi that are intolerant to high salt concentrations are killed. They die of exosmosis and plasmolysis.

” transportation question”

Question 10. (1) Since ancient times, dry woods have been used to crack rocks by placing them within the rocks. Which property is utilized here to produce the pressure? or (2) Write one application of that property in the human body.
Answer:

1. The property which is utilized to produce the pressure is imbibition.
2. Skin grafting (replacement by new skin) utilizes imbibition property. Newly grafted skin lacks capillaries. Under such conditions, O₂ and other substances are transported to the grafted skin by imbibition, until capillaries form.

Question 11. (1) What is the Casparian strip? or (2) What are passage cells?
Answer:

1. The suberin and lignin deposited between the inner wall and lateral wall of the endodermal parenchyma cells in mature plant roots is called the Casparian strip.
2. Casparian strips prevent the entry of water into the stele from the cortex. However, this strip is absent in some regions through which water is transported to the xylem vessels. The cells present in those regions, which allow water to enter are called passage cells.

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Question 12. (1) What is mycorrhiza? (2) How does it help to absorb water and minerals in roots?
Answer:

1. Roots of some phanerogams (like pine trees) are occupied by fungi to form symbiotic associations. These symbiotic associations between fungi and roots of phanerogams are called mycorrhiza.
2. Hypha of the fungi spread along the root. This increases the surface area for the absorption of water and minerals,- which in turn helps the plants.

Question 13. (1) Name the process and the plant part, by which terrestrial plants absorb water from soil. or (b) How do these plants absorb minerals and ions from soil?
Answer:

1. Terrestrial plants absorb water from the soil by the process of endosmosis through root hairs.
2. Terrestrial plants obtain minerals and ions from soil either dissolved in water or freely (when no water is being absorbed) by passive or active absorption methods.

Question 14. (1) When and in which type of plants do guttation occur? Which plant part is involved in guttation? (2) What is the main cause of guttation?
Answer:

1. Guttation mainly occurs at night and in the early morning in the spring season, in some plants of tropical areas. It occurs through the permanent openings called hydathodes, located at the leaf margins.
2. The main cause of guttation is root pressure.

Question 15. Describe the role of microfibrils of guard cells in opening and closing of stomata.
Answer: According to recent studies, it has been stated that the arrangement of microfibrils in guard cells controls the opening and closing of stomata. The cellulosic microfibrils are arranged parallel and radially. This lengthwise increase of microfibrils helps in the opening of stomata.

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Question 16. (1) Upto what height can water rise through the xylem vessel, due to transpiration? or (2) Which component of the xylem vessel is like a capillary tube that takes part in the ascent of sap?
Answer:

1. Experimentally it has been proved that, due to transpiration pull, water can rise up to a height of 130m through a xylem vessel.
2. The tracheids and trachea of the xylem vessel act as fine capillary tubes and they help in the ascent of sap.

Question 17. (1) Which tissue is involved in the transport of solute in higher plants? (2) Which components of that tissue help in the transport of solute?
Answer:

1. Transport of solute occurs through phloem tissue in phanerogams.
2. Sieve tubes and companion cells of phloem tissue are involved in the translocation of solute.

Question 18. (1) What is a sieve plate? or ( 2) How do the cells of sieve tubes maintain connections between them?
Answer:

1. The transverse, porous plate present between the consecutively arranged, columnar cells of mature sieve tubes, is called a sieve plate.
2. The cells of sieve tubes maintain connections between them by fine cytoplasmic projections and plasmodesmata that extend through pores in sieve plates.

Question 19. Transport of solute is bidirectional Explain.
Answer:

The facts that support the statement are as follows—

1. The organic food produced in the leaf of photosynthetic plants is transported downward through phloem tissue to roots and stems. There, it is utilized to produce energy and the excess food is stored in the form of starch.
2. Deciduous plants shed their leaves in winter, due to which they cannot photosynthesize. During this condition, the stored food in roots and stem are converted to simple sugar. This simple sugar is then transported upward to different parts of the plant.

Class 11 Biology WBCHSE Transport In Plants Very Short Answer Type Questions

Question 1. What do you understand by antitranspirant?
Answer: The chemicals that reduce the rate of transpiration in plants, when applied to leaf surfaces, without disrupting normal metabolic activity are called antitranspirants. For example, wax

Question 2. What is water potential?
Answer: The difference between the free energy of a molecule of pure water and the free energy of water in any other sample under normal pressure and temperature, is called water potential.

Question 3. What is wall pressure?
Answer: The opposite pressure applied by the cell wall against the turgor pressure in a fully turgid cell, is known as wall pressure.

Question 4. What is the unit of water potential?
Answer: The unit of water potential is bar. 1 bar = 0.987 atmosphere = 106 dyn/cm2.

Question 5. A flowering plant is planted in an earthen pot and watered. A lot of urea is added to make the plant grow faster, but after some time the plant dies. Name the process responsible for this.
Answer: The process is called exosmosis.

Question 6. In a plant cell, the cytoplasm is surrounded by both cell wall and cell membrane. However, it has been observed that the transport of substances across the cell membrane is very specific. Which feature is responsible for this?
Answer: The cell membrane is selectively permeable, so it shows specificity during the transport of substances.

Question 7. What do you understand by pressure potential?
Answer: When a cell is kept immersed in pure water, endosmosis occurs which increases the turgidity that pushes the cell organelles towards the membrane, generating turgor pressure. This is called pressure potential.

Question 8. A plant cell is kept in an aqueous solution and it gets plasmolyzed. What is the nature of the solution?
Answer: The nature of the solution is hypertonic.

Question 9. What is facilitated diffusion?
Answer: The process of diffusion across the membrane with the aid of a carrier is called facilitated diffusion

Question 10. Write three effectors that influence water potential.
Answer: Concentration, pressure, and relative density influence water potential.

Question 11. What is meant by wilting?
Answer: Wilting is the loss of turgidity by the cells at soft aerial parts like leaves and young branches. It occurs when the rate of transpiration is higher than the rate of water absorption.

Question 12. Which instrument is used to measure the magnitude of water absorption in the plant body?
Answer: The absorption of water is measured by a photometer.

Question 13. Name the minerals, that control the opening and closing of stomata.
Answer: Na, K Cl, etc., regulate the opening and closing of stomata.

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Question 14. What is passive absorption?
Answer: When water is absorbed by root hairs without utilizing any metabolic energy, it is known as passive absorption.

Question 15. What does the expression mean—Ψ_w=ψ_s+Ψ_p?
Answer: This expression means that water potential is the sum of osmotic potential (or solute potential) and pressure potential

Question 16. What is chemical potential?
Answer: The free energy of 1 mole of any substance is called its chemical potential.

Question 17. How osmotic pressure is controlled by temperature?
Answer: Osmotic pressure is directly proportional to temperature. It means when temperature increases, osmotic pressure too increases.

Question 18. What is known as the epithem?
Answer: The thin-walled parenchyma cells with extensive intercellular spaces which are found in hydathodes, are called epithem.

Question 19. How is transpiration related to the ascent of sap?
Answer: If the rate of transpiration increases, the ascent of sap will also increase. Therefore, transpiration is directly proportional to the ascent of sap.

Question 20. What is the water potential of pure water?
Answer: The water potential of pure water is zero.

Question 21. What is apoplast?
Answer: The pathway by which the passive transport of water and dissolved minerals occur through the cell wall of the plant cell, is called apoplast.

Question 22. What is meant by diffusion pressure?
Answer: The pressure that develops due to the kinetic energy of diffusible ions across the membrane is called diffusion pressure.

Question 23. Which plant hormone regulates the opening of stomata?
Answer: Cytokinin hormone controls the opening of stomata.

Question 24. What is known as capillary water?
Answer: The water that is present as non-colloid within soil particles is called capillary water.

Question 25. What is the approximate water potential of root hair?
Answer: The approximate water potential of root hair is 2 bar.

Question 26. Which enzyme makes transportation through cell membranes easier?
Answer: The transmembrane enzyme protein permease enables membrane transport.

Class 11 Biology WBCHSE

Question 27. Where does root pressure develop?
Answer: Root pressure develops in the xylem cells of the root

Question 28. If a plant cell of advanced species, that is surrounded by deposition of cutin and suberin, is kept in water for 15 minutes, what will happen then?
Answer: The volume of the cell will remain the same because cutin and suberin are impervious to water.

Question 29. Plant cell does not burst if immersed in pure water. Why?
Answer: The elasticity, tough structure, and extensibility of the cell wall of plant cells prevent it from bursting if immersed in pure water.

Question 30. State True or False: Active absorption utilizes ATP
Answer: True