Tag: absorption by roots - the processes involved

Questions Related to absorption by roots - the processes involved

Root pressure can be demonstrated by means of 

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

  1. Wilting

  2. Guttation

  3. Transpiration

  4. Exudation/bleeding

Show answer
Correct Option: D
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'.

Choose the correct answers from the alternatives given.
Root pressure can be measured by

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

  1. Osmometer

  2. Potometer

  3. Manometer

  4. Porometer

Show answer
Correct Option: C
Explanation:

Different processes can be measured by various apparatus.

A. Osmometer is used to measure osmotic pressure (pressure needed to stop the solvent to pass through the semi-permeable membrane).
B. Potometer is used to measure transpiration rate (the rate at which transpiration occurs).
C. Manometer is used to measure the root pressure (pressure that is exerted by roots such that it allows sap to rise through the plant stem to the leaves).
D. Porometer is used to measure stomatal conductance in leaves.
Hence, the correct answer is 'Manometer'.

A root hair cell under ordinary conditions have a water potential in the range of?

biology absorption by roots - the processes involved manure manures and fertilisers water absorption organ

  1. $-1$ to $-4$ atm.

  2. $-1$ to $+4$ atm.

  3. $1$ to $2$ atm.

  4. $-1$ to $2$ atm.

Show answer
Correct Option: A

Which of the following is an important feature of roots which help them to absorb water and minerals from the soil?

biology absorption by roots - the processes involved manure manures and fertilisers water absorption organ

  1. Roots provide very less surface area

  2. Cells of root contain cell sap

  3. Root hairs have thick walls

  4. All of the above

Show answer
Correct Option: B
Explanation:

Larger surface area and thinner walls of root hair are required to absorb water efficiently. 

Cells of the root contain sap which has an accumulation of ions which significantly reduces the water potential. Hence water enters the cells from the soil passively. 
So the correct answer is ' Cells of root contain cell sap'. 

The cells of the roots contain cell sap at a .................. concentration than that of surrounding soil water.

biology absorption by roots - the processes involved manure manures and fertilisers water absorption organ

  1. Higher

  2. Lower

  3. Equal

  4. All of the following

Show answer
Correct Option: A
Explanation:

The cells of the roots contain cell sap (solution) at a higher concentration than that of surrounding soil water. As a result, the water is absorbed by the root hairs. This is because the water always travels from a region of high water potential to the region of lower water potential. Here, the soil possesses a higher water potential as compared to the root hair.

Mineral absorption occurs.

biology absorption by roots - the processes involved manure manures and fertilisers water absorption organ

  1. If soil solution is hypotonic

  2. If soil solution is hypertonic

  3. Independent of water potential

  4. Independent of water absorption

Show answer
Correct Option: D

Rupture and fractionation of water column present in tracheary elements does not occur during ascent of sap due to

biology absorption by roots - the processes involved manure manures and fertilisers water absorption organ

  1. Transpiration pull

  2. Weak gravitational pull

  3. Cohesion and adhesion

  4. Lignified thick walls

Show answer
Correct Option: C
Explanation:

Transpiratioal or gravitational pull exert strain so they are factors that can cause rupture of the column. 

Lignified walls are only present for structural support.
Cohesion ( attraction of water molecules towards each other) and adhesion (attraction of water molecules and the walls of the tube ) is the reason why  the column doesn't break as these attractive forces overcome the strain developed by Transpiration pull. 
So the correct answer is 'Cohesion and adhesion'.

In root hair, water enters due to.

biology absorption by roots - the processes involved manure manures and fertilisers water absorption organ

  1. Diffusion

  2. WP

  3. T.P.

  4. O.P.

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Correct Option: A

If a cell A with OP $10$ bars and TP $4$ bars is connected to cells B, A and D having OP and TP respectively $4$ and $4$, $10$ and $5$ and $7$ and $3$ bars, the flow of water will be.

biology absorption by roots - the processes involved manure manures and fertilisers water absorption organ

  1. C to A, B and D

  2. B to A, C and D

  3. D to A, B and C

  4. A to B, C and D

Show answer
Correct Option: A

Which of the following elements are most readily mobilised?

biology absorption by roots - the processes involved manure manures and fertilisers water absorption organ

  1. Phosphorus, sulphur, nitrogen and potassium

  2. Calcium, sulphur, nitrogen and phosphorus

  3. Phosphorus, sulphur, nitrogen and calcium

  4. Potassium, sulphur, nitrogen and calcium

Show answer
Correct Option: A
Explanation:

Phosphorus, sulphur, nitrogen and potassium most readily mobilise while calcium is structural component which is not remobilised.