IV. Plant Physiology – Biology - MCQs

 

Multiple Choice Questions (MCQs)

 

The primary force responsible for the ascent of sap in tall trees is:

a) Root pressure

b) Imbibition

c) Transpiration pull

d) Guttation

 

Answer: c) Transpiration pull

 

Movement of water through the cell walls and intercellular spaces is known as the:

a) Symplast pathway

b) Apoplast pathway

c) Transmembrane pathway

d) Cytoplasmic streaming

 

Answer: b) Apoplast pathway

 

Water potential (Ψ w) is the sum of:

a) Solute potential (Ψ s) and Pressure potential (Ψ p )

b) Solute potential (Ψ s ) and Gravity potential (Ψ g )

c) Pressure potential (Ψ p) and Matric potential (Ψ m)

d) Solute potential (Ψ s ) and Matric potential (Ψ m)

 

Answer: a) Solute potential (Ψ s) and Pressure potential (Ψ p)

 

When a plant cell is placed in a hypertonic solution, it undergoes:

a) Turgor

b) Plasmolysis

c) Deplasmolysis

d) Imbibition

 

Answer: b) Plasmolysis

 

The opening and closing of stomata are primarily regulated by the turgidity of:

a) Epidermal cells

b) Subsidiary cells

c) Guard cells

d) Mesophyll cells

 

Answer: c) Guard cells

 

The pressure exerted by the cell contents on the cell wall is called:

a) Wall pressure

b) Turgor pressure

c) Osmotic pressure

d) Root pressure

 

Answer: b) Turgor pressure

 

Which of the following is an example of active transport?

a) Diffusion of gases

b) Facilitated diffusion of ions

c) Uptake of mineral ions by root hairs

d) Movement of water through osmosis

 

Answer: c) Uptake of mineral ions by root hairs

 

The hypothesis that explains the translocation of sugars in plants is the:

a) Cohesion-tension theory

b) Root pressure theory

c) Mass flow hypothesis

d) Pressure flow theory

 

Answer: c) Mass flow hypothesis (also known as Pressure flow hypothesis)

 

Guttation is the loss of water from the plant in the form of liquid droplets through:

a) Stomata

b) Lenticels

c) Hydathodes

d) Cuticle

 

Answer: c) Hydathodes

 

Which process involves the movement of molecules from a region of higher concentration to a region of lower concentration, without the requirement of metabolic energy, and with the help of membrane proteins?

a) Simple diffusion

b) Active transport

c) Osmosis

d) Facilitated diffusion

 

Answer: d) Facilitated diffusion

 

The end product of glycolysis is:

a) Acetyl CoA

b) Pyruvic acid

c) Lactic acid

d) Ethanol

 

Answer: b) Pyruvic acid

 

The site of Krebs cycle (TCA cycle) in eukaryotic cells is:

a) Cytoplasm

b) Mitochondrion matrix

c) Inner mitochondrial membrane

d) Outer mitochondrial membrane

 

Answer: b) Mitochondrion matrix

 

How many ATP molecules are theoretically generated during the complete aerobic respiration of one glucose molecule?

a) 2

b) 32-38

c) 28-30

d) 4

 

Answer: b) 32-38 (depending on shuttle systems, often simplified to 36 or 38)

 

Fermentation is a type of:

a) Aerobic respiration

b) Anaerobic respiration

c) Photorespiration

d) Cellular respiration that generates maximum ATP

 

Answer: b) Anaerobic respiration

 

The respiratory quotient (RQ) for carbohydrates is:

a) 0.7

b) 0.9

c) 1.0

d) >1.0

 

Answer: c) 1.0

 

Which of the following is an amphibolic pathway?

a) Glycolysis

b) Krebs cycle

c) Electron Transport System

d) Fermentation

 

Answer: b) Krebs cycle

 

The process of breaking down complex organic substances into simpler ones, with the release of energy, is called:

a) Anabolism

b) Catabolism

c) Metabolism

d) Photosynthesis

 

Answer: b) Catabolism

 

In anaerobic respiration, if oxygen is absent, pyruvic acid can be converted into:

a) Lactic acid or Ethanol

b) Acetyl CoA

c) Carbon dioxide and water

d) Glucose

 

Answer: a) Lactic acid or Ethanol

 

Which plant hormone is primarily responsible for cell elongation and apical dominance?

a) Gibberellin

b) Cytokinin

c) Auxin

d) Abscisic acid

 

Answer: c) Auxin

 

Bolting (internode elongation) in rosette plants is promoted by:

a) Auxin

b) Ethylene

c) Abscisic acid

d) Gibberellin

 

Answer: d) Gibberellin

 

The plant hormone associated with fruit ripening is:

a) Auxin

b) Gibberellin

c) Ethylene

d) Cytokinin

 

Answer: c) Ethylene

 

Which plant growth regulator is known as the 'stress hormone' and plays a role in seed dormancy and stomatal closure?

a) Auxin

b) Cytokinin

c) Gibberellin

d) Abscisic acid (ABA)

 

Answer: d) Abscisic acid (ABA)

 

The ability of a plant cell to dedifferentiate and then redifferentiate into a new cell type is called:

a) Plasticity

b) Totipotency

c) Differentiation

d) Redifferentiation

 

Answer: b) Totipotency

 

The phenomenon where plants require a cold treatment for flowering is known as:

a) Photoperiodism

b) Vernalization

c) Stratification

d) Scarification

 

Answer: b) Vernalization

 

Short-day plants flower when:

a) The light period is longer than a critical photoperiod.

b) The light period is shorter than a critical photoperiod.

c) They are exposed to continuous light.

d) They are exposed to continuous darkness.

 

Answer: b) The light period is shorter than a critical photoperiod.

 

The dormant state of the seed due to internal conditions, preventing germination even under favorable external conditions, is called:

a) Quiescence

b) Dormancy

c) Stratification

d) Vernalization

 

Answer: b) Dormancy

 

The increase in girth of a plant stem or root is due to:

a) Primary growth

b) Secondary growth

c) Differentiation

d) Elongation

 

Answer: b) Secondary growth

 

Which hormone promotes cell division, particularly in tissue culture?

a) Auxin

b) Gibberellin

c) Cytokinin

d) Ethylene

 

Answer: c) Cytokinin

 

The initial stage of seed germination primarily involves:

a) Photosynthesis

b) Imbibition of water

c) Respiration

d) Root development

 

Answer: b) Imbibition of water

 

The process of development in plants that is determined by the environment is called:

a) Differentiation

b) Dedifferentiation

c) Plasticity

d) Redifferentiation

 

Answer: c) Plasticity