Tiêu đề TRANSPORT IN PLANTS.pdf ✅

Aakash Educational Services Limited - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph. 011-47623456 SECTION - A 1. Answer (1) Water potential of pure water at standard temperature which is not under any pressure is taken as zero. 2. Answer (2) Absorption of water by seeds and dry wood is called imbibition. 3. Answer (2) Surface tension represents a phenomenon which explains that water molecules are attracted to each other in liquid phase more than to water in gas phase. Transpiration  Water loss in form of vapour. Adhesion  Attraction of water molecules to polar surface Cohesion  Mutual attraction between water molecules. 4. Answer (2) Solute potential is the lowering of water potential of a solution. Solute potential of any solution is always negative. 5. Answer (1) Calcium is an immobile element. 6. Answer (4) In both simple diffusion and facilitated diffusion, movement of molecules occur along the concentration gradient. 7. Answer (1) Turgor pressure is the pressure of cytoplasm exerted on the cell wall of the cell. 8. Answer (1) Active absorption of minerals ions is not a function associated with transpiration. 9. Answer (4) Mass flow of sucrose in phloem does not require ATP i.e. passive process. 10. Answer (2) Microfibrils in the cell walls of guard cells are made up of a polysaccharide. That polysaccharide is cellulose. 11. Answer (3) Transport of substances from their low to high concentration is an uphill transport. 12. Answer (2) For a solution at atmospheric pressure w (water potential) = s (solute potential) Solutions Chapter 8 Transport in Plants
16 Transport in Plants Solutions of Assignment Aakash Educational Services Limited - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph. 011-47623456 13. Answer (2) At the sink, sucrose is moved out of the phloem sap by active transport as a result the osmotic pressure inside sieve tube elements decreases. 14. Answer (2) Endodermis acts as control point and it adjusts the quantity and types of solutes entering in xylem tissues. 15. Answer (3) Transpiration develops a negative water potential in the xylem which creates a ‘pull’ for translocation of water while root pressure is a positive hydrostatic pressure responsible for pushing of water. 16. Answer (4) In girdling experiment, a ring of bark upto the depth of the phloem layer is carefully removed. In a girdled plant, root cells die first than the shoot cells, due to stoppage of translocation of sugars and other materials to the roots. 17. Answer (2) In guard cells, cellulose microfibrils are radially oriented. 18. Answer (2) Herbaceous plants lose water in the form of droplets through special openings called hydathodes due to high root pressure. This process is called guttation. 19. Answer (4) Loading of sucrose in sieve tube cells via companion cells is an active process. 20. Answer (4) In facilitated diffusion, transport of ions/molecules occurs with the help of specific membrane proteins called transporters. This process is highly specific because transporter proteins are highly selective. The rate of facilitated transport may saturate. Facilitated diffusion is a passive transport. 21. Answer (1) Intercellular movement of water occurs through cytoplasmic connections between neighbouring cells. These structures are called plasmodesmata. 22. Answer (3) Water potential of pure water is zero at atmospheric pressure. By increasing external pressure on pure water, its water potential increases. 23. Answer (2) 24. Answer (3) External hypertonic solution 25. Answer (2) w = Water potential S = Solute potential p = Pressure potential 26. Answer (4) Xylem translocates water and minerals and phloem translocates synthesised food. 27. Answer (3) 28. Answer (2) 29. Answer (4) 30. Answer (3) Addition of solutes increases the osmotic pressure. During phloem loading, sucrose moves into the phloem which increases its OP and becomes hypertonic. Phloem loading is an active process. At the sink, osmotic pressure in sieve tube decreases and water moves out of the phloem.
Solutions of Assignment Transport in Plants 17 Aakash Educational Services Limited - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph. 011-47623456 31. Answer (4) Xylem is associated with translocation of mineral salts, water, organic nitrogen and hormones. Phloem transports photosynthates. 32. Answer (3) Facilitated diffusion involves movement of substances through membrane proteins. Hydrophilic substances cannot move through the lipid bilayer hence these molecules are facilitated by some membrane proteins. 33. Answer (3) Osmotic concentration is directly proportional to the amount of solutes. If cell sap has high osmotic concentration, it means it has more solutes and it is hypertonic as compared to the surrounding solution. 34. Answer (1) Water moves from high water potential to low water potential. Water potential of cell A and C = –10 bar Water potential of cell B = –8 bar 35. Answer (3) SECTION - B 1. Answer (1) Active transport is uphill transport and requires energy. Both are dependent on sperial membrane proteins. 2. Answer (4) Lowering of water potential is solute potential. 3. Answer (3) 4. Answer (3) Imbibition is reversible. 5. Answer (2) Number of stomata, root shoot ratio and ABA are plant factors. 6. Answer (3) Cuticular transpiration is maximum upto 50% in herbaceous plants. 7. Answer (3) Given means of transport is facilitated diffusion. It does not require energy. 8. Answer (2) 9. Answer (1) 10. Answer (2) In all plants, the transport of xylem is unidirectional. 11. Answer (3) Symplastic system is a living system which is connected through plasmodesmata. 12. Answer (2) 13. Answer (1) 14. Answer (3) In a turgid cell DPD = O. Hence, OP = TP. 15. Answer (2) Cell A, w = s +p = –12 + 9 = –3 Cell B, w = –12 Cell C, DPD = OP – TP
18 Transport in Plants Solutions of Assignment Aakash Educational Services Limited - Regd. Office : Aakash Tower, 8, Pusa Road, New Delhi-110005 Ph. 011-47623456 DPD = 12 – 7 DPD = 5 w = –5 Water moves from high to low water potential. 16. Answer (2) For flaccid cell p = 0. Hence, w =s + p w = –25 17. Answer (2) 18. Answer (2) More the amount of solutes, more high is the solute potential. 19. Answer (2) 20. Answer (2) Water is lost during transpiration. Hence w decreases. 21. Answer (4) 22. Answer (3) 23. Answer (2) (i) Osmotic pressure (iii) Cannot (ii) Pure water (iv) Symplastic 24. Answer (3) Phloem loading is an active process. 25. Answer (3) Root pressure can push water upto a certain height. Water movement in tall tress is due to transpiration. 26. Answer (4) Water moves from its region of higher chemical energy to region of lower chemical energy. 27. Answer (1) (c), (d), (e) are seen in active transport only 28. Answer (4) 29. Answer (3) At sink OP is low. 30. Answer (1) SECTION - C 1. Answer (3) Active transport is uphill transport which requires membrane proteins and ATP. It is highly selective. 2. Answer (4) When a plant cell is placed in hypotonic solution water will flow into the cell as water moves from high water potential to low water potential. 3. Answer (3) In active transport, materials are transported across a membrane with the help of mobile carrier protein and ATP. In passive transport, substances move along the concentration gradient, i.e., from its higher concentration to its lower concentration.