A few drops of sap were collected by cutting across a plant stem by a suitable method. The sap was tested chemically. Which one of the following test results indicates that it is phloem sap?
1. Acidic
2. Alkaline
3. Low refractive index
4. The absence of sugar
Assertion: Like animal cells, sodium ions play the primary role in basic transport processes in plant cells.
Reason: In plant cells, the membrane potential is established mainly through pumping of sodium ions by sodium-potassium pumps.
1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.
Assertion: Water transport across biological membranes is too specific and too rapid to be explained entirely by diffusion through the lipid layer.
Reason: Water molecules are so small that they move relatively freely across the lipid bilayer, even though the middle zone is hydrophobic.
1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.
Assertion: Nutrients pass easily through the sieve tube members of Phloem.
Reason: Though alive, sieve tube members lack such organelles as the nucleus, ribosomes and a distinct vacuole.
1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.
Assertion: Given equal cross sectional areas of xylem, a plant with larger-diameter vessels can move more water up its stems than a plant with narrower tracheids.
Reason: The volume of liquid moving in a column per second is inversely proportional to where r is the radius of the column, at constant pressure.
1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.
Assertion: Blue light as a signal induces stomatal closure.
Reason: Blue light inhibits proton transport.
1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.
Assertion: Removing sinks is a useful horticulture practice such as in production of larger sized apples.
Reason: If sinks are more than the source can support, plants may undergo self-thinning.
1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.
The molar concentration of a sugar solution in an open beaker has been determined to be 0.3M. The solution is kept at 27 degree Celsius. The solute potential will be about:
1. - 3.75
2. - 7.48
3. - 9.18
4. 0
Identify the incorrect statement regarding plasmolysis in plant cells:
1. If a plant cell is placed in a hypertonic solution, the plant cell loses water and hence turgor pressure by plasmolysis.
2. If cytorrhysis occurs the plant will wilt.
3. Plasmolysis can be reversed if the cell is placed in a hypotonic solution in many cases.
4. Convex plasmolysis is always reversible.
Arrange the following events in the correct chronological order during opening of the stomata:
I. An uptake of potassium ions occurs into the guard cells.
II. A proton pump drives protons (H+) from the guard cells.
III. Diffusion of water occurs into the guard cell through osmosis.
IV. The two guard cells lengthen by bowing apart from one another.
V. Negative ions flux into the guard cells to balance the influx of potassium.
1. I, III, II, IV, V
2. I, II, V, III, IV
3. II, I, V, III, IV
4. II, V, I, III, IV