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

Turgor pressure develops in the epidermal cells of roots when there is:

  1. high water potential in the cytoplasm of cortical cells

  2. entry of water into root hair and increase in volume of cell sap

  3. a large vacuole in root hair filled with cell sap

  4. osmotic diffusion of water into the pericycle through passage cells
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Turgor pressure develops when water enters the root hair by osmosis, increasing the volume of cell sap (vacuolar contents). This influx against the cell wall creates turgor. Option A incorrectly references water potential in cortical cells. Option C describes a large vacuole but not the pressure mechanism. Option D describes pericycle transport, not root hair turgor.

Multiple choice

The loss of water in a liquid form is called _______.

  1. hydathodes

  2. transpiration

  3. diffusion

  4. guttation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Guttation is the loss of water in liquid form through hydathodes (specialized pores) usually from leaf margins. This occurs when transpiration is low and soil moisture is high, creating root pressure. Transpiration is water loss as vapor.

Multiple choice

The chief water conducting elements of ferns and gymnosperms are

  1. vessels

  2. fibres

  3. tracheids

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

Ferns and gymnosperms lack vessels (evolved in angiosperms) and rely on tracheids as their chief water-conducting elements. Tracheids are long, thin cells with tapered ends that transport water and provide structural support. Sieve elements are for food transport.

Multiple choice

Plant cells do not burst when kept in an hypotonic solution due to the presence of

  1. vacuole

  2. plastids

  3. cell wall

  4. nucleus

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

When plants are placed in water, the water enters their cells (this is because their sap has a strong solution). The water enters the plant through osmosis and fills up the cell with water to its maximum capacity. A strong cell wall stops the cells from bursting (as in animal cells) and makes the plant to become turgid (becomes rigid/stiff because of water).

Multiple choice

Ascent of sap can be explained by _______ experiment

  1. Thistle-funnel

  2. Potato osmoscope

  3. Ringing

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

The ringing experiment (girdling) involves removing a ring of bark (phloem) from a plant stem while leaving the xylem intact. This demonstrates that organic nutrients (sugars) are transported through the phloem, as food accumulates above the ringed portion, causing swelling. The ringing experiment proves the existence and direction of phloem transport (translocation), which is part of the sap ascent mechanism.

Multiple choice

Abscission in a plant is the

  1. wilting and falling of leaves

  2. opening of stomata

  3. elongation of shoots

  4. fruit growth

  5. phototropic and geotropic responses of the plant
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is the correct option.

Multiple choice

Hygroscopic water is attached to the soil particle by means of a force called

  1. Osmosis

  2. Diffusion

  3. Capillarity

  4. Imbibition
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Hygroscopic water is held as a thin film around soil particles by imbibition forces - the attraction between water molecules and colloidal soil particles. It's so tightly held that plants cannot absorb it. Osmosis and diffusion are water movement processes, not attachment forces. Capillarity is water movement in narrow spaces due to surface tension.

Multiple choice

Which of the following statements is incorrect?

  1. All parts of a plant perform respiration individually.

  2. Roots of plants take oxygen required for respiration through diffusion.

  3. Oxygen diffuses in root hair and transports to other cells for respiration.

  4. Roots of a land plant respire anaerobically.

  5. There is little transport of respiratory gases during respiration in plants.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This is the correct answer as this statement is incorrect.

Multiple choice

Lamina is modified into pitcher to store water in

  1. nepenthes

  2. saracaenia

  3. dischidia

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

 Lamina is modified into pitcher to store water in dischidia.This is a device to catch insects for fulfilling the deficiency of nitrogen in the medium where plant is growing.

Multiple choice

What happens in thigmotropism movement?

  1. Movement of curvature, in which a plant organ, i.e. roots, turn away from water current

  2. The movement of plants, in response to touch or physical contact

  3. Plant movement in response to one sided injury

  4. Plant movement, in which the organs of plants track the sun across the sky
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The movement of plants in response to touch or physical contact is known as thigmotropism.