Transport in Plants

NEET Biology · 57 questions · Page 6 of 6 · Click an option or "Show Solution" to reveal answer

Q51

What is the direction of movement of sugars in phloem?

A Non-multidirectional

B Upward

C Downward

D Bi-directional

Correct Answer

Option D

Solution

(d) Phloem transport is bidirectional — from source to sink in either direction.

Q52

Phenyl mercuric acetate (PMA) results in

A reduced photosynthesis

B reduced transpiration

C reduced respiration

D killing of plants

Correct Answer

Option B

Solution

(b) PMA is an antitranspirant — reduces transpiration without affecting gas exchange significantly.

Q53

Transpiration is least in

A good soil moisture

B high wind velocity

C dry environment

D high atmospheric humidity

Correct Answer

Option D

Solution

(d) High atmospheric humidity reduces the water potential gradient → least transpiration.

Q54

In guard cells when sugar is converted into starch, the stomatal pore

A closes completely

B opens partially

C opens fully

D remains unchanged

Correct Answer

Option A

Solution

(a) Sugar → starch: osmotic concentration falls → guard cells lose water → stomata close.

Q55

At constant temperature, the rate of transpiration will be higher at

A Sea level rise

B 1 km below sea level

C 1 km above sea level

D 1.5 km above sea level

Correct Answer

Option D

Solution

(d) At higher altitudes, lower atmospheric pressure increases transpiration rate.

Q56

Conversion of starch to organic acids is required for

A stomatal opening

B stomatal closing

C stomatal formation

D stomatal activity

Correct Answer

Option A

Solution

(a) Starch → malic acid (organic acid) via PEPC; raises osmotic pressure of guard cells → stomata open.

Q57

In terrestrial habitats, temperature and rainfall conditions are influenced by

A water transformations

B transpiration

C thermoperiodism

D translocation

Correct Answer

Option B

Solution

(b) Transpiration contributes to atmospheric moisture, influencing local temperature and rainfall.

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