NCERT Class 11-Biology: Chapter –11 Transport in Plants Part 4

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Question 11:

Given below is a table. Fill in the gaps

Chapter 11 - Question 11 Table of Fill in Thr Gaps
Chapter 11 - Question 11 Table of Fill in thr Gaps

Property

Simple diffusion

facilitated transport

Active Transport

i.

Highly selective

____________________

Yes

_________________

ii.

Uphill transport

____________________

_________________

Yes

iii

Requires ATP

____________________

_________________

__________________

Answer:

Chapter 11 - Question 11 Table of Fill in Thr Gaps
Chapter 11 - Question 11 Table of Fill in thr Gaps

Property

Simple diffusion

facilitated transport

Active Transport

i.

Highly selective

No

Yes

Yes

ii.

Uphill transport

No

No

Yes

iii

Requires ATP

No

No

Yes

Question 12:

Define water potential and solute potential.

Answer:

The kinetic energy of water is called water potential. Water potential reduces when a solute is dissolved in it. The magnitude of lowering of water potential because of solute is called solute potential.

Question 13:

Why is solute potential always negative? Explain

Answer:

Water potential is the sum of solute potential and pressure potential . So when solute is dissolved in water, the water potential of pure water decreases or starts assuming a negative value.

Solute potential also known as osmotic potential is the potential of solution that allows the water to enter the solution by diffusion or osmosis due to presence of the solute in it. Pressure potential is the hydrostatic pressure that is exerted on water present in a cell. This usually has a positive value.

Question 14:

An onion peel was taken and

a. Placed in salt solution for five minutes.

b. After that it was placed in distilled water.

When seen under the microscope what would be observed in a and b?

Answer:

(a) When the Tradescantia leaf epidermal peel was taken and placed in salt solution for five minutes, the cells would have shrinked when seen under the microscope because salt solution is hypertonic causing water to move out of the cell thus leading to exosmosis.

(b) After that when it was placed in distilled water, the cell regains its turgidity as it absorbs water and deplasmolysis occurs.

Question 15:

Differentiate between Apoplast and Symplast pathways of water movement. Which of these would need active transport?

Answer:

Apoplast and Symplast Pathways of Water Movement
Apoplast and Symplast pathways of water movement

Property

Apoplast

Symplast

Composition

Consists of non-living parts of the plant

Consists of living parts of the plant

Water diffusion by

Water diffusion occurs by passive diffusion

Water diffusion occurs by osmosis

Resistance to movement of water

Resistance is less to water movement

Resistance is more to water movement

Question 16:

How does most of the water moves within the root?

Answer:

Water moves from the soil to the roots via the process of osmosis. The water potential in the soil is more than in the cytoplasm of the root hair. So water passes across the semi-permeable membrane of the root hair cell into the root via osmosis. Then the water is passed on to the xylem vessels where water either would travel through cortex or would go through the cell walls. Now the water keeps on moving upwards via the xylem vessels by diffusion due to the water potential gradient present. The water upon moving to the leaves, it diffuses to the mesophyll cells then into the spaces between the cells after which it vaporizes out through the stomata via the process of transpiration (loss of water from the aerial parts of the plant in form of water vapour). This whole process is driven by capillarity and root pressure. The driving force is the water potential that is established.

Question 17:

Give the location of casparian strip and explain its role in the water movement.

Answer:

Casparian strips are situated in the endodermal cell walls (radial and transverse) of plant roots. It prevents movement of water from pericycle to cortex thus promoting and establishing a positive hydrostatic pressure. Casparian strips blocks the apoplastic pathway due to which water has to enter the symplastic pathway.

Question 18:

Differentiate between guttation and transpiration.

Answer:

Difference between guttation and transpiration are:

Difference between Guttation and Transpiration
Difference between guttation and transpiration

Property

Transpiration

Guttation

Definition

Water is lost from the plant by aerial parts of the plant in form of water vapour

Water is lost from margins of leaves in form of water droplets

Occurs through

Mostly through stomata

Through structures called hydathodes

Loss of water in form of

Water vapour

Water droplets

Takes place during

Day

Early morning

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