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Mechanism of absorption - class-XI

Description: mechanism of absorption
Number of Questions: 15
Created by:
Tags: botany mineral nutrition in plants plant physiology transpiration biology transport in plants the leaf
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Generally, gravitational water is utilized by the plants.

  1. True

  2. False


Correct Option: B
Explanation:
Gravitational water is free water moving through soil by the force of gravity. It is largely found in the macropores of soil and very little gravitational water is available to plants as it drains rapidly down the water table in all except the most compact of soils.

So, the correct answer is 'False'.

Ion channels have been discovered by 

  1. Singer and Nicolson

  2. Garnier

  3. Robinson and Brown

  4. Neher and Sakmann.


Correct Option: A

Activation energy is required for

  1. Exothermal reactions

  2. Endothermal reactions

  3. Enzyme mediated reactions

  4. Starting all biochemical reactions


Correct Option: D
Explanation:

Activation energy is the minimum amount of energy required to initiate a chemical reaction.

So, the correct answer is 'Starting all biochemical reactions'. 

Slow rate of absorption of ion at high temperature is due to

  1. Low photosynthetic rate

  2. Low rate of transpiration

  3. Enzyme inactivation

  4. All the above


Correct Option: C
Explanation:

At high temperature more than 500500 C the enzymes become inactive which effect the rate of absorption of minerals from soil.

Salt respiration is?

  1. Linking of ion movement with respiratory chain

  2. Active increase in respiration during mineral absorption

  3. Decrease in respiration during salt absorption

  4. Secretion of salt through respiratory channels


Correct Option: B

Lecithin carrier theory of mineral absorption was proposed by.

  1. Pfeffer $(1900)$

  2. Lundegardh and Burstrom $(1933)$

  3. Bennet - Clark $(1956)$

  4. Lundegasdh and Pfeffer $(1964)$


Correct Option: C

Which of the following statement is incorrect?

  1. Rise of water in a narrow tube is inversely proportional to the radius of the tube

  2. A water melon has over 92% water

  3. Dry plant material can imbibe ether but rubber cannot imbibe

  4. when water flows into thew cells and out of the cell and are in equilibrium, the cells are said to be flaccid


Correct Option: A

Metabolic water is the one

  1. Used during transamination

  2. Used during photosynthesis

  3. Produced during aerobic utilization of glucose

  4. Produced during condensation or polymerisation


Correct Option: C

Features of PUFA do not include

  1. Insoluble in $H _2O$

  2. High melting temperature

  3. Contains double bonds

  4. Lower occurrence of cardiovascular risks


Correct Option: B
Explanation:

PUFA or polyunsaturated fatty acids are not soluble in water. They have more than one double bond in their fatty acid chain. Polyunsaturated fatty acids (PUFA) contain multiple double bonds and are not stacked together that leads to the weaker intermolecular interaction; as a result, the melting point of PUFA has a lower melting point. PUFA improves blood cholesterol levels and thus lower the risk of cardiovascular diseases. 

So, the correct answer is option B, High melting temperature. 


Choose the correct answer from the alternatives given.
Which of the following minerals is required for all phosphorylation reactions?

  1. Nitrogen

  2. Iron

  3. Magnesium

  4. Phosphorus


Correct Option: D
Explanation:

Phosphorylation is a biochemical process that involves the addition of phosphate to an organic compound.

So the correct answer is "phosphorus".

With reference to absorption of minerals, the term 'outer space' represents ______ while 'inner space' represents _______. 

  1. Intercellular space and cell wall; cytoplasm and vacuole

  2. Cytoplasm and vacuole; intercellular space and cell wall

  3. Intercellular space; vacuole

  4. Cytoplasm; vacuole


Correct Option: A

In feedback inhibition, a metabolic pathway is switched off by

  1. Lack of a substrate

  2. Accumulation of the end product

  3. A rise in temperature

  4. Competitive inhibition


Correct Option: B
Explanation:

Accumulation of the end product triggers inhibition or switching off of the metabolic pathway in feedback inhibition mechanism. 

So, the correct option is 'Accumulation of the end product'. 

The main constituents of cytoplasm is C, N, O, H. These are derived from-

  1. Protein

  2. Carbohydrate

  3. Water

  4. None of these.


Correct Option: C

In the initial phase of mineral ion absorption, there is a rapid uptake of ions into ______ space of cells. Ions absorbed in this phase are ______ exchangable. It is _____ uptake as it ______ the expenditure of metabolic energy.

  1. inner, not freely, active, requires

  2. inner, freely, passive, requires

  3. outer, freely, passive, does not require

  4. outer, not freely, active, requires.


Correct Option: C
Explanation:

In the principal stage, an underlying fast take-up of particles into the 'free space' or 'space' of cells the apoplast, is detached.

So, the correct option is 'outer, freely, passive, does not require'.

Choose the correct option

  1. $E\quad +\quad S\quad \longrightarrow \quad ES\quad \longrightarrow \quad E+P\quad \longrightarrow \quad EP$

  2. E\quad +\quad S\quad \longrightarrow \quad ES\quad \longrightarrow \quad EP\quad \longrightarrow \quad E+P

  3. E\quad +\quad S\quad \longrightarrow \quad ES\quad \longrightarrow \quad EP\quad \longrightarrow \quad E+P

  4. E\quad +\quad S\quad \longrightarrow \quad ES\quad \longrightarrow \quad EP\quad \longrightarrow \quad E+P


Correct Option: A
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