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

The stomata in angiosperms open and close due to

  1. the presence of gases inside the leaves

  2. their genetic constitution

  3. turgor pressure of guard cells

  4. turgor pressure of subsidiary cells
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The stomata in angiosperms open and close due to turgor pressure of guard cells.

Multiple choice

If a flower is cut open and dipped in NaCl solution then

  1. transpiration is low

  2. exosmosis occurs

  3. no bacterial growth takes place

  4. absorption of solute, inside flower cell takes place.

  5. -
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In this the solution is hypertonic and the flower cell is hypotonic. Water will leave the flower cell, hence exosmosis will occur.

Multiple choice

Opening and closing of stomata is due to

  1. Ca2+

  2. Na+

  3. K+

  4. Cl-

  5. -
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

As K+ levels increase in the guard cells, the water potential of the guard cells drops, and water enters the guard cells. The loss of water by the guard cells causes them to become flaccid and the stomatal opening to close.

Multiple choice

Submerged hydrophytes show

  1. stomata

  2. abundant air sacs

  3. developed mechanical tissue

  4. secondary growth

  5. -
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Correct Answer: abundant air sacs

Multiple choice

Mosses occur in moist places because

  1. they cannot grow on land

  2. their gametes fuse in water

  3. they lack vascular tisuue

  4. they lack root and stomata
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Since moss gametophytes have no vascular system to transport water through the plant or waterproofing systems to prevent tissue water from evaporating, they live in a damp environment in which to grow, they require a surrounding of water to reproduce.

Multiple choice

An auxanometer is used to detect

  1. respiration

  2. transpiration

  3. plant movement

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

An auxanometer is an apparatus for measuring increase or rate of growth in plants.

Multiple choice

Wilting of plant is because

  1. xylem is blocked

  2. phloem is blocked

  3. epidermis and few roots are removed

  4. pith is removed
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Wilting refers to the loss of rigidity of non-woody parts of plants. This occurs when the turgor pressure in non-lignified plant cells falls towards zero, as a result of diminished water in the cells. Wilting occurs by blocked xylem as xylem carries water in plants.

Multiple choice

Why do dry leaves catch fire more easily than green leaves?

  1. The dry leaves have high ignition temperature.

  2. The dry leaves have a lower ignition temperature.

  3. The dry leaves contain moisture which helps in burning.

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

The dry leaves have a lower ignition temperature and they do not have any moisture. So, they can burn easily.

Multiple choice

Which of the following theories gives the latest explanation for the closure of stomata?

  1. ABA theory

  2. Munch theory

  3. Starch glucose theory

  4. Active potassium transport theory

  5. -
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The opening of stomata occurs due to the influx of K+ ions into the guard cells. The source of K+ ions are the neighbouring subsidiary and epidermal cells. It increases the concentration from 50 mM to 300 mM in guard cells. The increase in K+ ion concentration increases the osmotic concentration of guard cells. It leads to stomatal opening. ATP helps in entry of K+ ions into the guard cells.