Biology Multiple Choice Questions on “Plant-Water Relations-1”.
1. Which part of the cell contains water-like substances with dissolved molecules and suspended in them?
a) Protoplasm
b) Cytoplasm
c) Cytosol
d) Matrix
Answer: a
Clarification: Protoplasm of the cell is a fluid, similar to water, contains all the molecules in it. Cytoplasm contains all the particles inside the membrane of a cell. Cytosol is a part of cytoplasm possessing all the organelles excluding the cell nucleus. Matrix is a fluid present in different types depending upon the type of specialized structure such as stroma is the matrix of chloroplast.
2. Woody parts of plants contain relatively less water while soft parts contain more water.
a) True
b) False
Answer: a
Clarification: Woody plants have dead vascular tissue so there is no conduction of water and do not contain much water. In case of soft parts, they have functional vascular tissue hence possess sufficient amount of water.
3. Statement A: Water is the limiting factor for plant growth and productivity.
Statement B: A minute amount of water is lost to the environment by the leaves.
a) Both the statements are true
b) Both the statements are false
c) Statement A is true but Statement B is false
d) Statement B is true but Statement A is false
Answer: c
Clarification: As water is lost in a large amount to the external surroundings due to many environmental and internal factors, hence, is the most important determinant of plant growth and productivity. More than 90% of water is lost to the environment by leaves due to transpiration and evaporation.
4. The amount of water lost by plants due to transpiration and guttation?
a) 98%
b) 12%
c) 92%
d) 50%
Answer: a
Clarification: The amount of water lost by plants due to transpiration and guttation is approximately 98%. Watermelon contains 92% of water. Herbs have 12% of their fresh weight as the dry matter. Mustard plant absorbs water having 50% of their weight in 5 hours.
5. Which potential is considered of negligible value?
a) Water potential
b) Matrix potential
c) Solute potential
d) Pressure potential
Answer: b
Clarification: Matrix potential is the energy developed due the attachment of water with non-dissolved solutes such as soil. It is of negligible value whereas Water potential is the ultimate energy and Solute potential and Pressure potential are important components of water potential.
6. The value of water potential of pure water is ________
a) 1
b) -1
c) 0
d) -2
Answer: c
Clarification: The water potential of pure water is highest with the numerical value of 0. 1 cannot be the value of water potential and -1, -2 values come when solute is dissolved or pressure is applied.
7. Concentration gradient is a mandatory condition for diffusion of substances irrespective of the process involved.
a) True
b) False
Answer: a
Clarification: All the processes require a redox potential in order to transport substances from one place to another. A concentration gradient is an essential condition for the transport of molecules of substances to occur.
8. The greater concentration of water in a system leads to _________
a) increased transpiration
b) increased solute potential
c) hypertonic condition
d) greater kinetic energy
Answer: d
Clarification: Increase in concentration of water in a system leads to increase in K.E and thereby the water potential of the plant. It reduces hypertonic solution and aim to achieve isotonic condition. It decreases the solute potential as the water content increases in comparison to solutes dissolved. Transpiration doesn’t depend on amount of water present in the system.
9. The unit of water potential is_________
a) psi
b) no unit
c) pascal
d) mmole per kg
Answer: c
Clarification: Pascal is the unit of water potential as it is also a kind of pressure. Psi is the Greek symbol use to the denote water potential. It must have a unit as it is not a ratio. mmole per kg is the unit of amount of micro and macro nutrients required by the plant.
10. Statement A: Solute potential increases with dissolution of solutes.
Statement B: The value of solute potential is always negative.
a) Both the statements are true
b) Both the statements are false
c) Statement A is true but Statement B is false
d) Statement B is true but Statement A is false
Answer: a
Clarification: Solute potential is a component of water potential which alters it depending on the amount of dissolved solute added or removed as well as the amount of water present. Since maximum value of water potential is zero which contains no solutes. Addition of solute decrease the water potential, therefore, the increment of solute potential is in negative terms.