Prepare for NEET Biology Plant Growth and Development with MCQs & PYQs on NEET.GUIDE. Get free practice, previous year questions, and expert insights on plant hormones and growth regulators.
A plant hormone promotes bolting in rosette plants and is also antagonistic to the effects of abscisic acid on alpha-amylase activity. This hormone also plays a key role in apical dominance. Which of the following hormones fits this description?
Gibberellin
Auxin
Cytokinin
Ethylene
Which PGR is most likely responsible for the phenomenon observed when a plant bends towards a light source, even if the light source is unidirectional and doesn't illuminate the entire plant?
Cytokinin
Gibberellin
Auxin
Abscisic Acid
Ethylene is unique among plant growth regulators due to its:
Ability to promote cell division
Role in seed dormancy
Gaseous nature
Synthesis in the root apical meristem
Which of the following combinations of plant growth regulators are antagonistic in their action on apical dominance?
Auxin and Gibberellin
Cytokinin and Ethylene
Gibberellin and Abscisic Acid
Auxin and Cytokinin
The 'Richmond-Lang effect', which refers to the delay of senescence in leaves by cytokinins, is primarily attributed to their influence on:
Ethylene production
Cell wall synthesis
Nutrient mobilization
Stomatal closure
Which plant hormone is primarily responsible for inducing dormancy in seeds and buds, enabling them to withstand unfavorable environmental conditions?
Gibberellin (GA)
Auxin (IAA)
Cytokinin (CK)
Abscisic Acid (ABA)
A researcher observes that the growth rate of a plant significantly increases after the application of a specific hormone. Further analysis reveals that this hormone promotes cell elongation primarily in the intercalary meristem. Which hormone is most likely responsible for this observed growth?
Auxin
Cytokinin
Ethylene
Gibberellin
A particular mutation affects the synthesis of expansins in a plant species. Which of the following growth-related processes will be most directly impacted by this mutation?
Cell division in the meristem
Nutrient uptake from the soil
Photosynthetic efficiency
Cell wall loosening and expansion
Which of the following best describes the relationship between arithmetic growth and geometric growth in a typical organism's life cycle?
Arithmetic growth and geometric growth occur simultaneously.
Geometric growth always precedes arithmetic growth.
Arithmetic growth always precedes geometric growth.
Arithmetic growth often precedes or follows a period of geometric growth.
A plant exposed to unidirectional light exhibits phototropism. If the tip of the coleoptile is removed and replaced with a gelatin block, then illuminated from one side, which of the following will be observed?
The coleoptile will bend towards the light source.
The coleoptile will bend away from the light source.
The coleoptile will not bend towards the light source.
The coleoptile will exhibit random growth.
