Transport in plants practice · Mixed difficulty

Option A (Both (A) and (R) are true and (R) is the correct explanation of (A)) is correct because buds rely on stored sugars, and the source-sink relationship is indeed reversible based on the plant's needs.

Option A (Hypotonic) is correct because a hypotonic solution has a lower solute concentration than the cell, causing water to move into the cell.

Option C (Decreases) is correct because dissolving solutes in pure water lowers the water potential, making it more negative.

Option D (1 and 2) is correct because dry seeds and woody parts of plants have the least amount of water compared to other plant tissues.

Option D (Solute, solvent) is correct because osmosis is the movement of water (solvent) from a region of lower solute concentration to a region of higher solute concentration, effectively moving against the solute concentration gradient and along the solvent concentration gradient.

Option C (Movement down the concentration gradient) is correct because active transport moves substances against the concentration gradient, not down it.

Option D (All of these) is correct because the symplast includes the cytoplasm, protoplast, and plasmodesmata, all interconnected living components of plant cells.

Option B (Increases) is correct because an increase in temperature generally increases the rate of imbibition due to increased kinetic energy of water molecules and enhanced diffusion.

Option D (All of the above) is correct because all the statements about water absorption and transport are correct.

Option B (Water potential decreases) is correct because the accumulation of ions in guard cells decreases the water potential.

Option A is correct because the zone of cell differentiation, also known as the root hair zone, is where root hairs develop and absorb water and minerals.

Option A (Succulent plants) is correct because scotoactive stomata, which open at night and close during the day, are characteristic of succulent plants (CAM plants) adapted to arid environments.

Option D (Sieve elements) is correct because sieve elements are the primary cells responsible for the translocation of food materials in higher plants.

Option B is correct because the loading of sucrose into sieve tube elements is an active process, requiring energy to move sucrose against its concentration gradient.

Option B (1-5 atm) is correct because the magnitude of root pressure typically ranges between 1 to 5 atmospheres.

Option C (Pascal) is correct because water potential is measured in units of pressure, and the SI unit of pressure is the Pascal.

Option D (Water, mineral salts, some organic nitrogen and hormones) is correct because xylem transports a comprehensive mix of substances, including water, minerals, organic nitrogen, and hormones.

Option B (Imbibition) is correct because imbibition is the initial process by which dry seeds absorb water from their surroundings, leading to germination.

Option D is correct. Active transport is highly selective because it involves specific carrier proteins that bind to specific ions or molecules.

Option B (Decrease in size) is correct because NaCl dissociates into ions, increasing the solute concentration outside the cell, causing water to move out and the cell to shrink.

Option C (Both 1 and 2) is correct because bulk flow in plants can be driven by both positive (e.g., root pressure) and negative (e.g., transpiration pull) pressure gradients.

Option C ((A) is true but (R) is false) is correct because substances soluble in lipids diffuse faster, and the diffusion rate depends on both size and lipid solubility, not just size.

Option D (Attraction of water molecule to polar surface) is correct because adhesion is the attraction between water molecules and polar surfaces like xylem walls.

Option C (Carbon dioxide uptake) is correct because the zone of cell differentiation is primarily involved in water and mineral uptake, not carbon dioxide uptake.

Option D (Electrosmosis) is correct because Fensom and Jones proposed electrosmosis as a method for solute translocation in plants.

Option D (All of these) is correct because organic food or solutes can be translocated upwards, downwards, and radially within a plant through the phloem.

Option C is correct. Surface tension is a property of liquids but does not directly facilitate molecule transport across membranes or within plants.

Option C (water potential is zero) is correct because at full turgor, the pressure potential equals the osmotic potential, making the water potential zero.

Option C (Require the energy in the form of ATP) is correct because facilitated diffusion is a passive process and does not require ATP.

Option B (A-undirectionally; B-casparion strips) is correct because the endodermis transports ions unidirectionally due to the Casparian strips.