Biology

Plant Transport and Physiology

1,834 Questions

Access a comprehensive set of questions on plant transport mechanisms and physiological adaptations. Topics include water movement, translocation of food, and plant responses to external stimuli. These biology questions are essential for medical entrance exams and other science competitive tests.

Xylem and phloem transportTranspiration and evaporationPlant adaptationsGeotropic and phototropic responsesWater absorption by rootsRespiration in roots

Plant Transport and Physiology Questions

Multiple choice

Plants can synthesise their own food by

  1. transpiration

  2. evaporation

  3. photosynthesis

  4. precipitation

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Photosynthesis is the biological process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water.

Multiple choice

Abscisic acid causes

  1. slow movement of water out of the guard cells

  2. slow movement of K+ out of the guard cells

  3. rapid movement of water out of the guard cells

  4. rapid movement of K+ out of the guard cells
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Abscisic acid (ABA) acts as a stress hormone that triggers stomatal closure. It does this by inhibiting H+ pumps and promoting the rapid efflux of K+ ions from guard cells, which leads to water loss and turgor reduction.

Multiple choice

Stomata of CAM plants

  1. open during the night and close during the day

  2. never open

  3. are always open

  4. open during the day and close at night
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

CAM (Crassulacean Acid Metabolism) plants keep their stomata closed during the day to minimize water loss in arid environments and open them at night to take in CO2.

Multiple choice

Maximum transpiration occurs from

  1. dermal tissue

  2. ground tissues of scale leaves

  3. periderm and lenticels

  4. protoderm and procambium
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Stomatal transpiration, which occurs through the stomata located in the dermal tissue (epidermis) of leaves, accounts for the vast majority of water loss in plants.

Multiple choice

Most widely accepted explanation for the ascent of sap in plant is

  1. capillarity / Imbibition

  2. pulsating activity of living cells

  3. role of atmospheric pressure

  4. transpiration-cohesion theory
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The transpiration-cohesion-tension theory is the most widely accepted explanation for how water moves upward through the xylem against gravity. It relies on the cohesive properties of water and the pull generated by transpiration.

Multiple choice

In water-logged soil, plants do not grow properly

  1. because the soil is physiologically dry

  2. because the soil is physiologically wet

  3. due to excessive water

  4. due to shortage of water
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In water-logged soil, oxygen is displaced by water. This creates an anaerobic environment that prevents root respiration, making it difficult for the plant to absorb water, a condition known as physiological drought.

Multiple choice

A plant cell becomes turgid due to

  1. plasmolysis

  2. exosmosis

  3. endosmosis

  4. electrolysis
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Turgidity occurs when water enters the plant cell via endosmosis, causing the cell to swell and press against the cell wall. Plasmolysis is the opposite process where water leaves the cell.