Tag: conduction of water and minerals

Questions Related to conduction of water and minerals

Which is not true regarding active water absorption?

  1. Require energy

  2. Occurs only when transpiration is slow

  3. Living cells are essential

  4. Force develops in shoot


Correct Option: D
Explanation:
  • Active absorption of water occurs in root cells which utilizes the metabolic energy released through respiration. It is of two types. Osmotic absorption is when water is ab­sorbed from the soil into the xylem of the roots according to the osmotic gradient. And Non-osmotic absorption is when water is absorbed against the osmotic gradient. Usually, transpiration is passive absorption but when it is low active absorption occurs. 
  • It takes place in living cells.
  • The force for passive absorption develops in shoot not of active absorption. 

So, the correct answer is 'Force develops in shoot'.

Death of protoplasm is a pre-requisite for a vital function like

  1. Transport of sap

  2. Transport of food

  3. Absorption of water

  4. Gaseous exchange


Correct Option: C
Explanation:
  • Hollow space is needed to allow water to pass. Hence the cells have to be empty thus dead for that. As water gets transported to the upper part of the plant, more water is absorbed.

So, the correct option is 'Absorption of water'

Which of the following would not contribute to water uptake by plant cell?

  1. an increase in the water potential $\Psi $ of the surrounding solution

  2. a decrease in pressure on the cell exerted by the wall

  3. the uptake of solutes by the cell

  4. an increase in tension on the surrounding solution.


Correct Option: A
Explanation:

Plant absorb water from the soil by osmosis. Root hair cells are adapted for this by having a large surface area to speed up osmosis. The absorbed water is transported through the roots to the rest of the plant where it's used for different purposes. It's a reactant used in photosynthesis.

So, the correct option is 'an increase in the water potential of the surrounding solution.'

The active uptake of minerals depends upon

  1. Respiration

  2. Transpiration

  3. Photorespiration

  4. Dephosphorylation


Correct Option: A
Explanation:

Plants can absorb minerals that are dissolved in solution.The minerals present in the soil can be absorbed through their root hair cells. However, the concentration of minerals in the soil is very low. While water is absorbed by the plants through osmosis,  minerals are absorbed as ions by active transport (transport against the law of diffusion, by spending cellular energy). The cell membrane has transport proteins that allow the ions to cross the membrane. The ions then move upward through the xylem, to the leaves and other aerial parts of the plant. The absorption of minerals using respiratory energy is called active absorption and is influenced by temperature, oxygen concetration and respiratory poisons

Which of the following helps to move the water from root to xylem vessels?

  1. Stem cells

  2. Root cells

  3. Soil

  4. None of the above


Correct Option: B
Explanation:
In plants, transpiration is the process by which water and solutes are taken up by the roots and transported via the xylem to the leaves. 
The water passes from the soil to the root by osmosis. The long and thin shape of root hairs maximizes surface area and water passes from the soil to the root hairs. The next stage in the transpiration stream is water passing into the xylem vessels. The water either goes through the cortex cells (between the root cells and the xylem vessels) or it bypasses them – going through their cell walls. After this, the water moves up the xylem vessels to the leaves through diffusion.
So, the answer is B.

Identify the vascular tissues in plants.

  1. Xylem

  2. Phloem

  3. Stem

  4. Both A and B


Correct Option: D
Explanation:
Vascular tissue is an arrangement of multiple cell types in vascular plants which allows for the transport of water, minerals, product and of photosynthesis to be transported throughout the plant. There are two types of vascular tissues of a plant namely, xylem and phloem.
So the correct answer is 'Both A and B'.

The absorption of water is not affected when

  1. Soil is waterlogged (poorly aerated)

  2. Soil temperature increases

  3. Soil solution is highly concentrated

  4. Soil water is available in maximum


Correct Option: D
Explanation:

Absorption of water occurs via root hairs of roots through diffusion of water from high concentration to lower concentration.

Because transpiration pull induces the absorption of water. Thus when there is a scarcity of water inside the plant it absorbs water and it is not affected by maximal soil water present in the soil. 
So the correct answer is 'Soil water is available in maximum'.

For absorption of water, the roots act as 

  1. Sucking organs

  2. Osmotic system

  3. Manometer

  4. Anemometer


Correct Option: B
Explanation:

Osmosis occurs when there is a concentration gradient and water flows out from the region of high water potential to lower water potential. So for absorption of water roots act as an osmotic system because there is high er solute concentration (water) in the soil as compared to the roots due to which water is absorbed by the roots by osmosis.

So the correct answer is 'Osmotic system'.

Optimum temperature for water absorption by plants is

  1. $ 0^o - 5^o C $

  2. $ 5^o - 20^o C $

  3. $ 25^o - 35^oC $

  4. $ 40^o - 50^o C $


Correct Option: C
Explanation:

Temperature about 30°C favours water absorption. At higher tem­peratures water absorption is decreased. Also, low temperature decreases the permeability of the cell membrane. Metabolic activities of the root cells are decreased below the optimum temperature. 

So the correct answer is '25°C - 35°C'.

Choose the correct answers from the alternatives given.
An arachnid differs from a crustacean because:

  1. arachnids lack antennae

  2. arachnids are mostly aquatic and crustaceans are mostly terrestrial

  3. only arachnids shed their exoskeletons

  4. only arachnids have two major body segments of cephalothorax and abdomen


Correct Option: A
Explanation:
Crustaceans and Arachnida are classes of Phylum Arthropoda. Crustaceans have 2 pairs of antennae but in arachnids they are absent. 
So the correct answer is "arachnids lack antennae".