Transport in Plants — Page 4 | NEET Biology

Q31

Movement of ions or molecules in a direction opposite to that of prevailing electrochemical gradient is known as

A diffusion

B active transport

C pinocytosis

D brownian movement

Correct Answer

Option B

Solution

(b) Active transport: movement against electrochemical gradient using ATP.

Q32

Which of the following criteria does not pertain to facilitated transport?

A High selectivity

B Transport saturation

C Uphill transport

D Requirement of special membrane proteins

Correct Answer

Option C

Solution

(c) Facilitated diffusion cannot cause uphill transport (against gradient) — that requires active transport.

Q33

Water vapour and CO2 both pass through the same stomatal opening simultaneously because

A Both processes cannot happen simultaneously.

B Both processes can happen together because the diffusion coefficient of water and CO2 is different.

C The above processes happen only during night time.

D One process occurs during day time, and the other at night.

Correct Answer

Option B

Solution

(b) Both diffuse independently down their respective gradients; different diffusion coefficients allow simultaneous movement.

Q34

The main difference between active and passive transport across cell membrane is

A active transport occurs more rapidly than passive transport.

B passive transport is non-selective whereas active transport is selective.

C passive transport requires a concentration gradient across a biological membrane whereas active transport requires energy to move solutes.

D passive transport is confined to anionic carrier proteins whereas active transport is confined to cationic channel proteins.

Correct Answer

Option C

Solution

(c) Passive transport moves along concentration gradient; active transport requires energy.

Q35

What will be the direction of flow of water when a plant cell is placed in a hypotonic solution?

A No flow of water in any direction.

B Water will flow in both directions.

C Water will flow out of the cell.

D Water will flow into the cell.

Correct Answer

Option D

Solution

(d) Hypotonic solution (lower solute outside): water flows into the cell by osmosis.

Q36

Which of the following is not a feature of active transport of solutes in plants?

A Requires ATP

B Occurs against concentration gradient

C Non-selective

D Occurs through membranes

Correct Answer

Option C

Solution

(c) Active transport is highly selective — non-selectivity is not a feature.

Q37

Active and passive transports across cell membrane differ in

A passive transport is nonselective

B passive transport is along the concentration gradient while active transport is due to metabolic energy

C active transport is more rapid

D passive transport is confined to anions while active transport in confined to cations

Correct Answer

Option B

Solution

(b) Active transport requires metabolic energy (ATP) and goes against concentration gradient.

Q38

The process responsible for facilitating loss of water in liquid form from the tip of grass blades at night and in early morning is

A Root pressure

B Imbibition

C Plasmolysis

D Transpiration

Correct Answer

Option A

Solution

(a) Root pressure drives guttation — water exudes in liquid form from hydathodes at leaf tips.

Q39

The most widely accepted theory for ascent of sap in trees is

A capillarity

B role of atmospheric pressure

C pulsating action of living cell

D transpiration pull and cohesion theory of Dixon and Jolly

Correct Answer

Option D

Solution

(d) Dixon and Jolly's transpiration pull-cohesion theory is most widely accepted.

Q40

Guttation is mainly due to

A root pressure

B osmosis

C transpiration

D imbibition

Correct Answer

Option A

Solution

(a) Root pressure drives guttation through hydathodes on leaf margins.