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 biology cell and cell organelles cell membrane and cell wall cell wall cell division in embryo development

The cell membrane is selectively permeable, it can be best deduced by?

  1. The entry of water

  2. The entry of selective mineral salts

  3. Both A and B

  4. The rise of sap in plants
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A selectively permeable membrane will allow free passage of solvent or water molecules, however, the entry of solute particles will be selectively allowed. In other words, not all but selected solute particles will be allowed to pass through.
Multiple choice biology environmental pollution control of water pollution protecting our environment rules are for everyone

What is meant by root zone process?

  1. A control measure to prevent water pollution

  2. A process by which roots of plants are spread on the ground

  3. A control measure to prevent soil pollution

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

The root zone process is a biological wastewater treatment method that uses plants and their root systems to filter and purify water, acting as a control measure against water pollution.

Multiple choice botany mineral nutrition in plants hydroponics hydroculture essential and non-essential mineral elements nutrients and nutrition

In plants, minerals

  1. Help establish gradients across membranes

  2. Influence water movement into cells

  3. Maintain cell shape and growth

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

Minerals are very important for plants because:

1. They help in maintaining gradients across membrane's like potassium, Sodium, etc.
2. They influence water movement into the cell. For example Opening of stomata is caused by movement of water into guard cells due to influx of potassium.
3. Cell shape and growth is maintained. Example Calcium, etc
So the correct answer is 'All of the above'.

Multiple choice botany mineral nutrition in plants hydroponics hydroculture essential and non-essential mineral elements nutrients and nutrition

What is the key principle of the EBB and flow system in hydroponics?

  1. It floods and drains periodically

  2. It makes a tide flowing over the roots

  3. It sprays a mist of nutrients on the roots

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ebb and Flow, or Flood and Drain is a system involves the periodic flooding and draining of the nutrient solutions. Basically, there are two phases of its operation. The Flood is when the water and nutrients flow the growing areas, flowing over the plants' roots. The drain is when the water drains back to the reservoir. These two actions take turn continuously, and hence their name.

So, the correct option is ‘it floods and drains periodically’.

Multiple choice botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

Which of the tissue is more important for translocation of sucrose?

  1. Xylem

  2. Phloem

  3. Both of the above

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

Translocation of organic nutrients from the region of source or supply to the region of sink or utilisation is mostly in the form of sucrose. Phloem (sieve tubes or sieve cells) is the pathway for this translocation, as found put by stem girdling, sieve tube puncturing, radioautography and chemical analysis of sieve tube sap.

Multiple choice botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

The cohesion transpiration pull theory operates only in

  1. Passive water absorption

  2. Active water absorption

  3. Conditions favouring transpiration

  4. Conditions restricting transpiration
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • The cohesion-tension theory is a theory of intermolecular attraction that explains the process of water flow upwards (against the force of gravity) through the xylem of plants. 
  • Transpiration pull, utilizing capillary action and the inherent surface tension of water, is the primary mechanism of water movement in plants. 
  • Hence, The cohesion transpiration pull theory operates only in Conditions favouring transpiration.
  • So, the correct answer is 'Conditions favouring transpiration'.
Multiple choice botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

In plants the translocation of organic solutes take place through

  1. Epidermis

  2. Xylem

  3. Phloem

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

In vascular plants, water and minerals move through xylem, whereas sugars move through phloem. Ringing experiments prove that sugars move through phloem. If the phloem tissue is removed in a ring or girdle, the sugars cannot be transported to roots from aerial parts and plant dies. 

Multiple choice botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

A rising column of water does not break its connection in the xylem vessels, despite negative pressure or tension due to

  1. Cohesion among water molecules

  2. Strong transpiration pull

  3. Adhesion

  4. Surface tension
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cohesion-Tension or Cohesion Transpiration pull theory was put forward by Dixon and Jolly in 1894. It is also known as Dixon's theory of Ascent of Sap. The important points are: 

1. Cohesion (attractive force between water molecules) and Adhesion (attractive force between water and xylem channels) Forces.
2. Continuous water columns.

3. Transpiration pull.
Water molecules are held together by strong cohesion force which is due to hydrogen bonds amongst them. It is due to these forces that water forms a continuous column in xylem elements. If there is an air bubble or air gap in this continuous column then water will not rise in the xylem elements. This break in rise of water is called as cavitation.

Thus, the correct answer is option A.

Multiple choice botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

Which one explains ascent of sap ?

  1. Cohesion-tension theory of Dixon and Joly

  2. Starch-sugar interconversion

  3. Photosynthesis

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
(A)Cohesion transpiration pull theory proved that cohesion and adhesion support continuity of water columns and provide strength like a steel wire, transpiration pulls water columns towards leaves which causes ascent of sap.
(B)Starch sugar theory was given by Steward proposing that during daytime enzymes phosphorylase and converts starch into sugar increasing the osmotic potential causing ascent of sap.
(C)Photosynthesis is the process of formation of complex compounds, glucose using simple compounds like carbon dioxide, sunlight.
So, the correct answer is 'Cohesion-tension theory of Dixon and Jolly'.
Multiple choice botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

Most widely accepted theory of carbohydrate translocation is

  1. Mass flow theory

  2. Root pressure theory

  3. Imbibition theory

  4. Transpiration theory
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

(A) Mass flow theory proposes the transportation of food in the plants.

(B) Root pressure theory proposes the transportation of water in the plants through the root pressure.
(C) Imbibition theory proposes water transportation through pipes.
(D) Transpiration theory proposes water transportation due to the evaporation from the upper surface of the leaves.
So, the correct answer is 'Mass flow theory'.

Multiple choice botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

Cohesion transpiration pull theory of ascent of sap was proposed by 

  1. Munch

  2. Stephen Hales

  3. Dixon and Joly

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

Cohesion transpiration pull theory was proposed by Dixon and Jolly. They proved that cohesion and adhesion support continuity of water columns and provide strength like a steel wire, transpiration pulls water columns towards leaves which causes ascent of sap.

So, the correct answer is 'Dixon and Jolly'.

Multiple choice botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

According to mass flow hypothesis
(a) Sucrose is moved into the companion cells and then into the sieve tube by passive transport.
(b) Inside the phloem, an osmotic pressure gradient is generated that facilitates the mass movement in the phloem.
(c) Water in the adjacent xylem moves into the phloem by active process

  1. (a) and (c) are correct

  2. (b) and (c) are incorrect

  3. (a) and (c) are incorrect

  4. (a) and (b) are correct
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

Leaf photosynthates are transported to other parts of higher plants through

  1. Cambium

  2. Pith

  3. Xylem

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

Phloem is involved in transport of sugars. Phloem cells are living cells, which carry out the physiological process of sugar transport in higher plants.

Multiple choice botany plant physiology mineral absorption transport of food, water and minerals mineral transport theories of translocation transport in the phloem of plants

How many of the following features are related to Dixon and Jolly model of water transport in plants?
a. Cohesion between water molecules
b. Transpiration pull
c. Pushing of water by negative root pressure
d. Surface tension
e. Pushing of water by positive root pressure.

  1. $4$
  2. $5$
  3. $2$
  4. $3$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Dixon and Jolly model (Cohesion-Tension theory) relies on cohesion, adhesion, surface tension, and transpiration pull. Pushing by root pressure is not part of this specific model.