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 transport in plants diffusion transport in vascular plants types of transport

The movement of water and minerals in xylem and the movement of phloem sap in phloem is ............... and .................... respectively

  1. Unindirectional, bidirectional

  2. Bidirectional, bidirectional

  3. Bidirectional, unidirectional

  4. Unindirectional, unidirectional
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The movement of water and minerals in xylem and the movement of phloem sap in phloem is unidirectional and bidirectional respectively. Plants need water for their growth, and it uptakes water through the roots. Water that is taken by the roots has to reach all the leaves or branches, here the xylem function as transportation of water. Therefore, the movement of water and minerals in xylem is always an unidirectional. Whereas, the movement of phloem is bidirectional this is because, once the food is synthesized it is the phloem that transfers the food to all the parts of plants wherever it is necessary.

So, the correct answer is option A.

Multiple choice biology transport in plants diffusion transport in vascular plants types of transport

Choose the correct answer from the alternatives given.
By what method arc ions absorbed by plants?

  1. Along DPD gradient

  2. By molecular diffusion

  3. By carriers and pumps

  4. Along water potential gradients
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

 For plants to take up mineral ions, ions are moved into root hairs, where they are in a higher concentration than in the dilute solutions in the soil. Active transport (pumps) then occurs across the root so that the plant takes in the ions it needs from the soil around it. The root hair cells have carrier molecules on their surface that pick up the minerals and move them into the cell against the concentration gradient.

So, the correct option is, 'By carriers and pumps'.

Multiple choice biology transport in plants diffusion transport in vascular plants types of transport

The direction of water in Cycas leaflets is 

  1. Upward

  2. Downward

  3. Lateral

  4. Both A and B
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

(A) The upward flow of the water is seen in the roots of the plant.

(B) Downward flow is seen in the bulk transportation from leaf to every other part of the plant.
(C) Lateral flow of water is seen in leaf and roots due to the diffusion patterns.
So. the correct answer is 'Lateral'

Multiple choice biology types and parts of plants leaves root, stem, and leaves basics of roots and stem

The bulliform cells of leaves lose their turgidity during excessive _____________.

  1. Assimilation

  2. Transpiration

  3. Photosynthesis

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

In some grasses(isobilateral leaves), on epidermis, there are some larger, thin walled cells called bulliform cells are present, which in dry condition lose water through transpiration and thus the rolling up of leaves occurs, e.g., in Poa, Agropyron, Amophilla, etc.

Multiple choice biology types and parts of plants leaves root, stem, and leaves basics of roots and stem

Meaningful girdling (ringing) experiment can not be performed within sugarcane because

(a) its phloem is situated interior to xylem
(b) its stem surface is covered with worry coating
(c) its vascular bundles are not present in a ring
(d) its stem is thin $13$. Guttation is caused by

  1. Transpiration

  2. Osmosis/ DPD

  3. Root pressure

  4. Osmotic pressure
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Guttation is the process of loss of water from the surface of leaves in the form of liquid drops. Hydathodes are the openings through which guttation takes place that are present on the margins of leaves. It occurs when root pressure is high and transpiration is low. 
So the correct answer is 'Root pressure'.
Multiple choice biology types and parts of plants leaves root, stem, and leaves basics of roots and stem

In the leaves of strawberry, water appears to be exuded through leaf margins. This is due to the combination of:
i. Adhesion
ii. Root pressure
iii. Transpiration
iv. Guttation.

  1. i, ii and iii

  2. ii, iii and iv

  3. i, ii and iv

  4. Only i, & iv
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • Guttation is the process of loss of water from the surface of leaves in the form of liquid drops. Hydathodes are the openings through which guttation takes place that are present on the margins of leaves.
  • Guttation occurs when root pressure is high and transpiration is low. Guttation is frequently seen occurring at night in herbaceous plants growing under conditions of high soil moisture and high atmospheric humidity.
  • Water rises up in the process due to the property of Adhesion.
So, the correct option is 'i, ii and iv'.
Multiple choice biology types and parts of plants leaves root, stem, and leaves basics of roots and stem

Transpiration.

  1. There are stomata on the leaves of the plants.Through these opening the excess of water is thrown out in the form of water vapors. This process is called transpiration

  2. There are two guard cells around the opening of stomata.They have an external membrane. They control the opening and closing of the stomata.

  3. Also come amount of water is lost due to evaporation from the leaves.

  4. As a result, water level in the epidermal layer of the leaf decrease

  5. To compensate this loss,more water is brought to the leaves through the xylem.

  6. Transpiration thus helps in absorption of water and minerals and their distribution to all parts of the plant

  7. Root pressure pushes the water up during the night time.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Transpiration is the biological process where plants lose water in the form of vapor through the stomata on their leaves.

Multiple choice biology types and parts of plants leaves root, stem, and leaves basics of roots and stem

The droplets of water arranged at the edges of leaves of roses in the morning are

  1. Water drops condensed from the atmosphere during night at low temperatures

  2. Water transpired from the stomata and lenticels

  3. Water produced on the leaves from the reaction of hydrogen and atmospheric oxygen

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Water droplets formed on the edge, tip, or the underside of leaves is not dew because dew comes from water condensing from the air and tends to settle evenly on the leaf’s upper surface.
Transpiration is the evaporative loss of water by plant. When the soil is too wet, water penetrates the plant through its roots and this creates pressure that forces the water to exit the plant in the form of droplets. This process doesn’t occur during the day, because the leaf’s stomata are open at that time. It occurs when the stomata close down, i.e. at night and water pressure begins to build up. Therefore, the droplets can be noticed when the sun comes up in the morning, before the drops evaporate.
So, the answer is B.
Multiple choice biology types and parts of plants leaves root, stem, and leaves basics of roots and stem

Wilting occurs when there is ___________________.

  1. Transpiration higher than absorption

  2. Absorption higher than transpiration

  3. Higher relative humidity of atmosphere

  4. Excess root pressure
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Wilting occurs when the rate of water loss through transpiration exceeds the rate of water absorption by the roots, leading to a loss of turgor pressure in plant cells.

Multiple choice biology types and parts of plants leaves root, stem, and leaves basics of roots and stem

The process of loss of water through the leaves and stem is called

  1. Transpiration

  2. Respiration

  3. Photosynthesis

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

Transpiration is the processin which water vapours are released from stomata.

Respiration is a metabolic processes which breaks down complex organic molecules to release energy.
Photosynthesis is the synthesis of sugar in the presence of sunlight, carbon dioxide and water.
Pollination is the transfer of pollen from male organ to female organ of a flower. 
So the correct answer is 'Transpiration'.

Multiple choice biology types and parts of plants leaves root, stem, and leaves basics of roots and stem

In transpiration, water is lost in         form whereas in guttation water is lost in the form of          

  1. Vapour, liquid

  2. Liquid, vapour

  3. Solid, vapour

  4. Vapour, solid
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In transpiration water is lost in the form of vapour whereas in guttation water in the form of liquid is lost. The loss of water in transpiration is through stomata whereas in guttation, it occurs through hydathodes.

Multiple choice biology types and parts of plants leaves root, stem, and leaves basics of roots and stem

The process by which plants lose water from leaves by evaporation is called as

  1. Respiration

  2. Photosynthesis

  3. Transpiration

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

Transpiration is the process of release of water vapour from the stomata. 

Respiration is the process of breakdown of organic compounds to release energy.
Photosynthesis is the process of synthesis of food from inorganic compounds like carbon dioxide and water and sunlight.
Absorption is the uptake of substances into a system like absorption of water by the roots.
So the correct answer is ' Transpiration'.

Multiple choice biology types and parts of plants leaves root, stem, and leaves basics of roots and stem

Transpiration takes place maximum through which of the following structures in plants?

  1. Flowers

  2. Stem

  3. Leaves

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

Transpiration is the process of release of water vapour from the stomata.

The stomata are present on the leaves.
Their are other types of transpiration but 90% of it takes place through Stomata.
So the the correct answer is 'Leaves'.

Multiple choice biology types and parts of plants leaves root, stem, and leaves basics of roots and stem

Potometer works on the principle of -

  1. Potential difference between the tip of the

    tube and that of the plant

  2. Amount of water absorbed equals the amount

    transpired

  3. Osmotic pressure

  4. Root pressure
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
A potometer is also known as transpirometer, is a device used for measuring the rate of water uptake of a leafy shoot which is almost equal to the water lost through the transpiration. The causes of water absorption are photosynthesis and transpiration.
So, the correct answer is 'Amount of water absorbed is equal to the amount transpired'.