Biology

Plant Transport and Physiology

2,012 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

During differentiation, the cells undergo structural changes. Which of the following changes do(es) not occur in differentiation?

a. The cells lose their protoplasm. b. The cells regain the capacity of division under certain conditions. c. The cells develop a very strong, elastic lignocellulosic secondary cell wall.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

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

This is the correct option as this is not a change of differentiation. The cells regain the capacity of division under certain conditions in dedifferentiation.

Multiple choice

Which of the following statements is incorrect?

  1. Root cells create a difference in ionic concentration between roots and soil.

  2. Water is steadily pushed upwards from soil.

  3. Evaporation of water molecules for plants surface helps in upward movement of water.

  4. Water from the roots is not transported through root pressure at night.
Reveal answer Fill a bubble to check yourself
D Correct answer
Multiple choice

Water in the plants is transported by the tissue called

  1. phloem

  2. xylem

  3. leaves

  4. parenchyma
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Xylem is the vascular tissue responsible for transporting water and dissolved minerals from roots to all parts of the plant. It consists of dead, hollow cells (tracheids and vessels) that form continuous tubes for water movement. Phloem transports organic nutrients (sugars) in the opposite direction.

Multiple choice

How is transpiration important for a plant?

  1. It helps in absorption of minerals.

  2. It helps to regulate temperature.

  3. It is major driving force in movement of water in xylem.

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Transpiration serves multiple functions: it creates the transpiration pull that drives water movement through xylem, it helps cool leaves through evaporative cooling, and it aids in mineral absorption by maintaining water flow through roots. All three options are valid functions, making 'All of the above' the correct choice.

Multiple choice

How are products of photosynthesis transported to all parts of a plant?

  1. Through vessels and sieve tubes

  2. Through sieve tubes and companion cells

  3. Through tracheids and companion cells

  4. Through sieve tubes and parenchyma
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In plants, phloem is the tissue responsible for transporting organic nutrients, particularly the products of photosynthesis (sucrose). Phloem consists of sieve tubes (the conducting cells) and companion cells (which provide metabolic support to sieve tube elements). This combination allows efficient transport of sugars from source leaves to sink tissues.

Multiple choice

Consider the following statements :

  1. In climacteric fruits, ethylene stimulates its own production.
  2. Gibberellin present in a healthy stem cuases some of the new cells to differentiate as phloem.
  3. Loss of turgor in leaves stimulates the productions of abscisic acid Which of the statements given above are correct ?

  1. 1 and 2 only

  2. 2 and 3 only

  3. 1 and 3 only

  4. 1,2 and 3
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Climacteric fruits show autocatalytic ethylene production where ethylene stimulates its own biosynthesis. Gibberellins can cause phloem differentiation in stem tissue. Abscisic acid (ABA) production is triggered by water stress and loss of turgor pressure in guard cells. All three statements are physiologically accurate.

Multiple choice

Which one of the following statements is not correct ?

  1. Roots produce gibberellins

  2. The Casparian strips in roots are involved in controlling the types of minerals that enter the xylem water stream

  3. Lateral roots are initiated by cell division in the endodermis

  4. When Rhizobium converts N2 into nitrogenous compounds that are released into the host cells, energy is supplied by sugars from the legume root cells
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The question asks which statement is NOT correct. Lateral roots originate from the pericycle (a layer of cells inside the endodermis), not from the endodermis itself. The other statements are all accurate: roots do produce gibberellins, Casparian strips regulate mineral entry into the xylem, and Rhizobium's nitrogen fixation is powered by host-derived sugars.

Multiple choice

Which one of the following is a disease caused by zinc deficiency ?

  1. Die back of rice

  2. Khaira disease of rice

  3. Black heart of potato

  4. Brown spot of rice
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Black heart of potato is a well-documented zinc deficiency disorder causing internal necrosis. Khaira disease of rice is caused by zinc deficiency (not B). Die-back and brown spot of rice are typically associated with other nutrient deficiencies (copper and fungal causes respectively). The question asks which is caused by zinc deficiency, and C correctly identifies black heart of potato as a zinc-related disorder.

Multiple choice

The surface of the leaf, uniformly coated with a water resistant waxy cuticle ______________.

  1. protects the excessive evaporation of water and decreases the absorption of ultraviolet or blue light to reduce heating

  2. gives strength to weak leaves

  3. protects it from germs attack

  4. gives it a shiny appearance

  5. protects its green colour
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Yes, it is correct. The surface of the leaf is uniformly coated with a water resistant waxy cuticle that protects the leaf from excessive evaporation of water and decreases the absorption of ultraviolet or blue light to reduce heating.