Guard cells regulate Transpiration Answer : (b)

The cohesion-tension theory explains how water moves up through the xylem Answer : (a)

When a plant cell is placed in a hypertonic solution it will lose water by exosmosis. This process is called plasmolysis. The protoplasm will shrink and will move inwards and away from the cell wall. As a result, the hypertonic solution will occupy the space between the plasma membrane and the cell wall. Answer : (c)

According to the vital force theory, ascent of sap is due to active pulsation of the innermost layer of cortex. This theory was given by J.C Bose. Answer : (a)

Hydathodes are always associated with the vein ends of leaves. Stomata remain closed at night and opened in the day time. Hydathodes always remain open (both day and night). The opening and closing of stomata can be regulated by guard cells. Answer : (c)

Guttation is the exudation of drops of xylem sap on the tips or edges of leaves of some vascular plants, such as grasses, and a number of fungi. Answer : (a)

Wilting is the loss of rigidity of non-woody parts of plants. This occurs when the turgor pressure in non-lignified plant cells falls towards zero, as a result of diminished water in the cells. The rate of loss of water from the plant is greater than the absorption of water in the plant. Answer : (a)

Answer : (b)

Imbibition is the physical adsorption of water or moisture. A common example is swelling of wooden furniture, doors, windows and frames of doors and windows, because of adsorption of moisture due to imbibition. Answer : (b)

Exosmosis is the passage of a fluid through a semipermeable membrane toward a solution of lower concentration, especially the passage of water through a cell membrane into the surrounding medium. plasmolysis contraction of the protoplast of a plant cell as a result of loss of water from the cell. Temporary wilting is a condition when the amount of water lost from the plant during transpiration is greater the amount of water absorbed from the soil. Wilting is the loss of rigidity of non-woody parts of plants. This occurs when the turgor pressure in non-lignified plant cells falls towards zero, as a result of diminished water in the cells. Answer : (b)

Shrinkage of the protoplast of a cell from its cell wall under the influence of a hypertonic solution is called plasmolysis. Answer : (a)

the ascent of sap in plants is a passive physical process, which occurs under the influence of transpiration pull generated due to loss of water from aerial parts Answer : (b)

The principle by which blotting paper absorbs water is Capillary action The capillary action is based on the property of surface tension of liquid. Answer : (a)

Capillarity is the tendency of a liquid in a capillary tube or absorbent material to rise or fall as a result of surface tension. Tensile strength is defined as the ability of a material to resist a force that tends to pull it apart. Answer : (c)

Transpiration is the output of water from a plant, and absorption is the input of water into a plant. If output is low and input is high, pressure will be at its greatest. Root pressure is osmotic pressure within the cells of a root system that causes sap to rise through a plant stem to the leaves. Transpiration pull is the force which aids in drawing the water upward from roots to leaves. Thus if transpiration is high water will be lost resulting in lowering of root pressure Answer : (b)

Diffusion is Free movement of ions and gases from an area of high concentration to an area of low concentration. a - 4 Osmosis a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one. b - 3 The process of imbibition occurs mainly due to the presence of hydrophilic or lyophilic colloids. Water is imbibed through the sub microscopic capillaries present on the surface of the body. Substances such as cellulose and starch are hydrophilic and are imbibants c - 1 Plasmolysis is the process of water leaving plant cells, allowing the cytoplasm and plasma membrane to shrink away from the cell wall. d - 2 Answer : (d)

At constant temperature, the rate of transpiration will be higher at 1.5 km above the sea level. At lower atmospheric pressure there is increase in the rate of evaporation Answer : (d)

Statement 1 is not correct as :When plants are exposed to light the guard cells accumulate large amounts of K⁺. Light stimulate the active movement of K⁺ ions from surrounding cells into the vacuoles of the guard cells. statement 2 is correct as Generally a high pH favors opening and a low pH favors closing of the stomata. Statement 3 is correct as the K⁺ ions migrate, they are accompanied by Cl⁻; the anion apparently moves in response to electric difference created by the K⁺ uptake into the guard cells. Statement 4 is not correct as in guard cells, osmotic and hence water potentials become very negative due to the presence of K⁺ Cl⁻ potassium malate or dipotassium malate or both. Answer : (c)

Osmosis involves Diffusion of water from less to more concentrated side Answer : (d)

We know that water flows from lower DPD to higher DPD DPD= OP - TP Cell A DPD= 5 -4 = 1 Cell B DPD = 7 - 5 = 2 Cell C DPD = 3-2 = 1 Cell D DPD = 0 -0 =0 Since Cell D have lowest DPD water will flow maximum from cell D Answer : (a)

hypotonic solution ( hypo = low concentration of solute) water will eneter in cell or show endosmosis Answer : (c)

According to Steward's starch hydrolysis theory steps are as follows Photosynthesis (1) ↓Decreased CO2Concentration in leaf cells (2) ↓Increase in pH of guard cells(3) ↓ Hydrolysis of starch to sugar by enzymes (4) ↓ Increase of O.P. of guard cells(5) ↓ Endosmosis of water in guard cells (6) →Increase in T.R of guard cells (7) ↓Aperture opens Answer : (d)

Pure water at atmospheric pressure has a solute potential of zero. As solute is added, the value for solute potential becomes more negative. solute potential: (osmotic potential) pressure which needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane. Hence zero for pure water Answer : (a)

Tracheid are less efficient than vessels due to Presence of tapering end walls Answer : (d)

Cohesion-tension theory is related to Ascent of sap Answer : (b)

Suberin, cutin and lignins are complex, higher plant epidermis and periderm cell-wall macromolecules, forming a protective barrier. Its main function is as a barrier to movement of water and solutes Water can not enter the cells Answer : (c)

Relative humidity – Relative humidity (RH) is the amount of water vapor in the air compared to the amount of water vapor that air could hold at a given temperature. Thus decrease in RH will increase rate of transpiration Answer : (b)

Wilting appears due to excessive Transpiration Answer : (d)

Guard cells regulate Closing and opening of stomata Answer : (d)

Imbibition is a special type of diffusion when water is absorbed by solids-colloids causing an enormous increase in volume. Due to incresed volme exerted high pressure on bottle causes blew up Answer : (b)