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 absorption by roots - the processes involved root pressure transportation in plants factors affecting the transport of water and minerals in plants

Root pressure can be demonstrated by means of 

  1. Wilting

  2. Guttation

  3. Transpiration

  4. Exudation/bleeding
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Root exudates function in below ground plant defence. Plant roots are constantly exposed to a variety of natural enemies, including pathogenic microorganisms and root-feeding arthropods. These organisms inhabit the soil surrounding the root system, which is designated the rhizosphere. 

Chemicals secreted into the soil by roots are referred to as root exudates. By doing this root changes the chemical and physical property of soil and inhibit the growth of other plant species. Root pressure can be demonstrated by means of exudation or bleeding caused due to root pathogens.

so the correct answer is 'Exudation'.

Multiple choice water potential water potential and pressure plant water relation transport in plants biology

Water from soil enters into root hairs owing to

  1. Atmospheric pressure

  2. Capillarity

  3. Root pressure

  4. Osmotic pressure or diffusion

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

Osmotic pressure of the cell sap of root hairs is usually higher than the osmotic pressure of the soil water. Therefore, the diffusion pressure deficit (DPD) and the suction pressure in the root hairs become higher and water form the cell wall enters into then through the plasma membrane by osmotic diffusion.

Multiple choice water potential water potential and pressure plant water relation transport in plants biology

Choose the correct answers from the alternatives given :
In which one of the following processes the phenomenon of osmosis is not involved

  1. Water entering a mesophyll cell from xylem vessel element

  2. Water passing from root hair to adjacent cells

  3. Water from soil entering a root hair

  4. Water passing up a xylem vessel element to xylem vessel above it
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Osmosis is the movement of solvent from its higher concentration to its lower concentration across a semipermeable membrane. Movement of water through xylem element to xylem vessels above it occurs due to the cohesive force between the water molecules, suction pressure and transpiration pull.


So the correct answer is "Water passing up a xylem vessels element to xylem vessel above it".

Multiple choice biology plant growth growth rates and conditions for growth population ecology growth and development

In organs of plants there is a variation in rate of growth. It is first slow, then accelerated upto maximum and slows down to stand still. The period of vigorous growth is known as

  1. Lag phase

  2. Period of growth

  3. Grand period of growth

  4. Log phase
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
In organs of plants, there is a variation in rate of growth. Growth is divided into four phases, namely lag phase, log phase, stationary phase and death phase. Lag phase is slow. In this, there is very little or no bacterial growth. In this phase, bacteria are adjusting to environment and synthesizing biochemicals and nutrients. In log phase, the number of bacterial cells doubles at an exponential rate. It is the period of vigorous growth . In stationary phase, the rate of cell death is equal to the rate of cell division. In death phase, there is decrease in the bacterial population due to lack of nutrients and high toxin concentration.
Thus, the correct answer is option D.
Multiple choice botany breath and blood of life stomata and transpiration transport in organisms long distance transport of water different types of circulatory systems

Loss of water in the form of vapours from the living tissues of aerial plant parts is called _________________.

  1. Transpiration

  2. Guttation

  3. Bleeding

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

The loss of water in the vapour form from the exposed parts of a plant is called transpiration. The loss of water due to transpiration is quite high. It is 22 litre per day in sunflower, 36−4536−45 litres in apple and upto 11 tonne per day in elm tree.

Multiple choice botany breath and blood of life stomata and transpiration transport in organisms long distance transport of water different types of circulatory systems

Leaf pores/ stomata help in _______.

  1. Intake of $CO _2$ during photosynthesis
  2. Release of $O _2$ during photosynthesis

  3. Release of water vapour during transpiration

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

Stomata has 3 major functions:

1. Transpiration causing release of water vapour
2. Intake of carbon dioxide during photosynthesis
3. Release of oxygen during photosynthesis
So the correct answer is 'All of these'.

Multiple choice botany breath and blood of life stomata and transpiration transport in organisms long distance transport of water different types of circulatory systems

The mechanism of transpiration in plants is performed by:

  1. Stem

  2. Only leaves

  3. Flowers

  4. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Water loss by transpiration may take place from any part of the plant exposed to external atmosphere. It occurs, however, principally from the leaves and is known as foliar transpiration. Only, a relatively small quantity of water is transpired from the stem and is called cauline transpiration.
So, the correct answer is D.
Multiple choice botany breath and blood of life stomata and transpiration transport in organisms long distance transport of water different types of circulatory systems

The process of transpiration in plants helps in

  1. Opening of stomata.
  2. Absorption of $CO _2$ from atmosphere.

  3. Upward conduction of water and minerals.
  4. Absorption of $O _2$ from atmosphere.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
In plants transpiration develops a transpiration pull that pulls water and minerals upwards from root towards leaves
So, the correct answer is 'Upward conduction of water and minerals'
Multiple choice botany breath and blood of life stomata and transpiration transport in organisms long distance transport of water different types of circulatory systems

Which force arises between the water molecules of leaves due to transpiration?

  1. Cohesive forces

  2. Pressure force

  3. Suction force

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

A.Cohesive force – force of attraction present between the water molecules is called cohesive force. Due to this, water column maintains tensile strength.

B.Pressure force – force developed to accumulation of pressure.

C.Suction force – force exists in the sucking of water.

D.Adhesive force – force of attraction exists between the water molecules and walls of the vessels is called adhesive force. Due to this, capillarity exists in the water column.

So, the correct option is ‘cohesive force’.

Multiple choice botany breath and blood of life stomata and transpiration transport in organisms long distance transport of water different types of circulatory systems

The process of transpiration in plants helps in the

  1. Opening of stomata

  2. Closing of stomata

  3. Upward conduction of water and minerals

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

Transpiration is the loss of water by the stomatal openings of the aerial parts of the plant. This helps in the upward movement of water and minerals from the roots to the leaves by a cohesion-adhesion mechanism. 

Multiple choice botany breath and blood of life stomata and transpiration transport in organisms long distance transport of water different types of circulatory systems

The process of transpiration is a

  1. Diffusion

  2. Osmosis

  3. Active transport

  4. facilitated Diffusion
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
During the process of transpiration, the water moves up the xylem vessels to the leaves through diffusion. Diffusion takes place because there is a difference in water potential between water in the xylem vessel and the leaf (as water is transpiring out of the leaf). There is also a pressure change between the top and bottom of the xylem vessels, due to water loss from the leaves. This reduces the pressure of water at the top of the vessels. This means water moves up the vessels and then out of the leaves through diffusion.
So, the correct option is 'Diffusion'.
Multiple choice botany breath and blood of life stomata and transpiration transport in organisms long distance transport of water different types of circulatory systems

Water movement against gravity is caused by?

  1. Imbibition

  2. Transpiration

  3. Osmosis

  4. Diffusion
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Water movement against gravity is caused by transpiration. Transpiration is the process by which water is carried through plant roots to small pores of the leaves, where it changes to vapor and is released to the atmosphere. The mechanism of transport of water against gravity is by cohesive forces of water molecules. Water molecules cohere and are pulled up the plant by the tension, exerted by evaporation at the leaf surface. 

Thus, the correct answer is option B.
Multiple choice botany breath and blood of life stomata and transpiration transport in organisms long distance transport of water different types of circulatory systems

The shade of the tree is often cooler than exposed atmosphere, because of

  1. Photosynthesis

  2. Respiration

  3. Transpiration

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

Transpiration is a process of loss of water from a plant in vapour form. One of the benefits of transpiration is that it causes surface cooling because evaporation of water requires energy. Consumption of energy leads to a cooling effect on the leaf surface. Also because of more water vapour content in shade, a tree shade is cooler than area exposed to sunlight.