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 botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Which cells among the permanent tissue are impermeable to water?

  1. Parenchyma

  2. Collenchyma

  3. Both A and B

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

The chief mechanical tissue of the plant body composed of highly thick walled cell with little or no protoplasm is called as sclerenchyma. Sclerenchyma consist of lignin. Lignin deposition is so thick that the cell walls become strong, rigid and impermeable to water. 

Therefore, the correct answer is option D.

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Which of the following tissues is dead at maturity?

  1. Sclerenchyma

  2. Collenchyma

  3. Parenchyma

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

The chief mechanical tissue of the plant body composed of highly thick walled cell with little or no protoplasm is called as sclerenchyma. The thickening of cell wall is due to deposition of cellulose or lignin or both. Lignin deposited cells are said lignified. Sclerenchyma cells are dead at maturity because of the absence of protoplast. 

Therefore, the correct answer is option A.

Multiple choice botany plant tissues permanent tissues and their types simple permanent tissues tissues: plant tissues

Which cell is found in the husk of coconut?

  1. Xylem

  2. Sclerenchyma

  3. Collenchyma

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

The chief mechanical tissue of the plant body composed of highly thick walled cell with little or no protoplasm is called as sclerenchyma. The thickening of cell wall is due to deposition of cellulose or lignin or both. Lignin deposited cells are said lignified. Sclerenchyma is the tissue which makes the plant hard and stiff.

Therefore, the correct answer is option B.

Multiple choice bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

The rate of respiration undergoes a sharp rise followed by a when certain fruits ripen. This phenomenon is known as ____________.

  1. Climatic rise

  2. Climatic fall

  3. Climacteric rise

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

The sudden, temporary increase in the respiration rate of certain fruits during the ripening process is universally known as the climacteric rise. This phenomenon is typically accompanied by a surge in ethylene production.

Multiple choice biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

Fruit ripening is accelerated by

  1. Warm surroundings

  2. Increased nitrogen supply

  3. Reduced water supply

  4. Ethylene rich atmosphere
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Ethylene is a plant hormone. It is also called as ripening hormone. It is responsible for ripening of fruits. Fruit ripening is accompanied by increased rate of respiration. Ethylene rich atmosphere is used to accelerate the process of ripening of fruits like banana.

Thus, the correct answer is option D.

Multiple choice biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

Stomatal closing during full sunlight is best defined by

  1. Hormonal control
  2. $K^+$ion hypothesis
  3. $CO _2$ concentration

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

Many hormone-like abscisic acid (for closing)  cytokinin (for opening) and ethylene (for opening and closing both) are responsible for opening and closing of stomata. 

So the correct option is 'Hormonal control'.

Multiple choice biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

The deteriorative proceses in plants, that naturally terminates their functional life, are collectively called as ...............

  1. Wilting

  2. Abscission

  3. Plasmolysis

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

Senescence refers to a number of controlled processes which finally culminate in death of the plant part. Senescence is a controlled process and is generally responsible for conservation of precious part nutrients like nitrogen and phosphorous. The senescing plant part is separated from plant due to formation of an abscission layer which finally separated the plant part.

Multiple choice biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

A characteristic feature of some fruit ripening is sudden increase in respiration. It is known as

  1. Climacteric

  2. Anthesis

  3. Climatic

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

Certain fruits ripen with sudden rise in cellular respiration and ethylene production. Such fruits are called 'climacteric fruits'. Climacteric is considered final stage in fruit ripening process during which the fruit is maximum ripened with best taste for consumption. After that period, it starts to gradually deteriorate and the respiration returns to normal rate.

Hence the correct answer is 'Climacteric'.

Multiple choice biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

Stomatal closure under stress conditions is due to

  1. IAA

  2. ABA

  3. IBA

  4. 2, 4-D
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Stress hormone is a hormone produced during adverse environmental conditions. Abscisic acid (ABA) is called as stress hormone. Due to this hormone, plants respond to stresses conditions like cold, drought. Stomatal closure under stress condition is due to this hormone. It also promotes seed dormancy under adverse condition.

Thus, the correct answer is option B.

Multiple choice biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

Choose the correct answer from the alternatives given.
Closing of stomata are induced by:

  1. axing

  2. boxing

  3. abscise acid

  4. indole 3-acetic acid
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

ABA inhibits seed germination. ABA stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses.

So, the correct option is 'abscisic acid'. 

Multiple choice biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

Ethylene promotes water absorption by increasing the root's absorption surface. It promotes:

  1. Premability of cell membrane

  2. Rormation of root hairs

  3. Concentration of cell sap

  4. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Ethylene promotes water absorption by increasing the root's absorption surface. It promotes the elongation of the root hairs and the root itself and it is also responsible for increasing the cell permeability in some cases. It has also been observed to increase the osmotic pressure and the concentration of cell sap.

So, the correct answer is 'all of these'.
Multiple choice biology plant growth and development other plant hormones cytokinins, ethylene and abscisic acid plant hormones

Acid deposition weakens plants by damaging their

  1. Leaves

  2. Roots

  3. Stems

  4. All of them
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Acid deposition primarily damages the waxy cuticle of leaves, which leads to increased water loss and susceptibility to pathogens. While it can affect soil chemistry and roots indirectly, the direct primary damage is to the foliage.

Multiple choice biology plant growth and development other plant hormones cytokinins, ethylene and abscisic acid plant hormones

Phytotron is ......................

  1. Fish culture

  2. Plant hormone

  3. Animal hormone

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

Phytotron is a laboratory or a building with an organisation of number of growth chambers and green houses in order to grow plants under strictly controlled environmental conditions. The maintenance and preparation of growth chambers is taken care by phytotron staff  including pest control. 

Thus, the correct answer is option D. 

Multiple choice biology plant growth and development other plant hormones cytokinins, ethylene and abscisic acid plant hormones

Choose the correct answer from the alternatives given.
The phytochrome system helps to entrain the biological dock by indicating to a plant that light is present when:

  1. Pr is rapidly converted to Pfr

  2. Pfr is slowly converted to Pr

  3. Pr and Pfr are equal in concentration

  4. red light is absorbed by Pfr
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The biological clock is the seasonal or physiological activities of the plant which changes according to time, season etc. When the light is present at the time of the night, the phytochrome system sends the signal to the biological clock which results in the activation of phytochromes thus converting Pr (Inactive form) to Off (active form). This results in the flowering of plants.

So, the correct option is 'Pr is rapidly converted to Pfr'.

Multiple choice biology plant growth and development other plant hormones cytokinins, ethylene and abscisic acid plant hormones

Which one of the following substances plays an important role in biochemical defense of host plants?

  1. Mycotoxin

  2. Phytoalexin

  3. Pathotoxin

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

Phytoalexins are low-molecular-weight antimicrobial compounds synthesized by plants in response to infection or stress, playing a major role in their biochemical defense. Mycotoxins and pathotoxins are produced by pathogens, while vivotoxins are toxic substances contributing to disease symptoms.