Tag: biology

Questions Related to biology

In water-logged soil, plants do not grow properly because _______________.

transpiration major activities of living organisms biology

  1. The soil is physiologically dry

  2. The soil is physiologically wet

  3. Due to excessive water

  4. Due to shortage of water

Show answer
Correct Option: A

Which of the following will not make minerals more available to plants?

transpiration major activities of living organisms biology

  1. Increasing the rainfall in a wet forested area.

  2. Raising the pH of a very acidic soil.

  3. Tillering a packed-down or water-logged soil.

  4. Introducing fungi that can form mycorrhiza into a soil that lacks them.

Show answer
Correct Option: A
Explanation:

Increased rainfall will lead to washing away of mineral elements along water, hence, it will not make minerals more available to plants.

Which of the following is not the purpose of transpiration process?

transpiration major activities of living organisms biology

  1. Supplying water for photosynthesis

  2. Maintaining shape and structure of plants

  3. Translocation of sucrose from source to sink

  4. Cooling the leaf surfaces

Show answer
Correct Option: C
Explanation:

Transpiration is the process of loss of water through the aerial parts of the plant. It depends upon the amount of humidity level of the atmosphere.

When there is a high level of moisture then there is no concentration gradient between leaf and the atmosphere there is a minimum loss of water through transpiration. 
So, the correct answer is 'Translocation of sucrose from source to sink'.

Which of these is not the goal of transpiration?

transpiration major activities of living organisms biology

  1. Prevention of loss of water

  2. Helping in the absorption and transportation process

  3. Supplying water for photosynthesis

  4. Keeping the plant cool

Show answer
Correct Option: A
Explanation:

Transpiration helps in the absorption of carbon dioxide gas from the atmosphere and its transportation.

It also helps in maintaining the temperature of the plant by releasing water which gets evaporated taking away the heat of the plant.
Transpiration leads to water loss so it cannot prevent loss of water.
So the correct answer is 'Prevention of loss of water'.

Maximum water loss occurs through

transpiration major activities of living organisms biology

  1. Lenticles

  2. Hydathodes

  3. Stomata

  4. Cuticle

Show answer
Correct Option: C
Explanation:

Water is essential for plants, it absorbs water from the soil through roots. However, plants absorbs much water, but only a small amount of water is used for their growth and metabolism. Persisting 97 - 99.5% of absorbed water is lost by transpiration. Transpiration is the process of elimination water in the form of water vapour from the aerial parts such as leaves, flowers and stem. The leaves contains tiny pores called stoma which helps in the gas exchange of oxygen and carbon dioxide. More the stoma (pores) on the leaves result in the increase in the transpiration via stomata. The leaf with the bigger surface area will transpire more when compared to the lower surface area. Each stomata is gaurded by guard cells which helps in the opening and closing of stomata. When stomata are open, transpiration rates increase; when they are closed, transpiration rates decrease.

So, the correct answer is option C.

In hot summer day, plant cooling occurs due to

transpiration major activities of living organisms biology

  1. Transport of water from root to all parts of the plants.

  2. Loss of liquid water

  3. Water loss from entire plant

  4. Loss of water vapour from foliar surface

Show answer
Correct Option: D
Explanation:

In hot summer days when loss of water vapour occurs from foliar surface because these are the main site of water loss or transpiration and directly exposed to sunlight.

There is no effect on cooling of plants due to transport of water from root to all parts of the plant or water loss from entire plant.

Plant cooling occurs due to 

transpiration major activities of living organisms biology

  1. Assimilation

  2. Guttation

  3. Photorespiration

  4. Transpiration

Show answer
Correct Option: D
Explanation:

Transpiration is the evaporation of the water from the stomata of the plants. The water absorbed by the roots is transported up to the leaves where stomata are present. Stomata open during the daytime and increasing temperature results in loss of water in the form of vapours. This is similar to the sweating process that occurs in humans. It cools the plants during high temperature.

Assimilation is the use of minerals by plants.
Guttation is oozing out of water in liquid form during night-time.
Photorespiration is a deviation in photosynthesis when the concentration of oxygen increases.
Transpiration is evaporation of water due to increased temperature during daytime.
So, the correct answer is 'Transpiration'.

Water lost through transpiration is 

transpiration major activities of living organisms biology

  1. Pure water

  2. Rich in organic solutes

  3. Rich in dissolved salts

  4. All of the above

Show answer
Correct Option: A
Explanation:

Transpiration is the process of the evaporation of water molecule from the upper surface of the leaves.

The water eluted out is the water without any solute concentration, so the water is pure.
So, the correct answer is 'Pure water'.

To cut stem, xylem sap come out due to ____________.

transpiration major activities of living organisms biology

  1. Transpiration

  2. Guttation

  3. Root pressure

  4. None of the above

Show answer
Correct Option: A

Choose the correct answers from the alternatives given.
According to transpiration pull-cohesion theory of ascent of sap, water is pulled upward through the xylem. The cause of the pull is 

transpiration major activities of living organisms biology

  1. Transpiration

  2. Guttation

  3. Root pressure

  4. Condensation

Show answer
Correct Option: A
Explanation:

Water is pulled upwards through the plants due to transpiration. Transpiration is the loss of water in the form of water vapour through stomata. The model that explains this translocation of water is called Cohesion-tension transpiration pull model of water transport. Less than one percent of water reaching the plant is used in photosynthesis and plant growth.

Hence, the correct answer is'Transpiration'.