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.
During human embryonic development, the formation of the primitive streak marks a crucial step. Which of the following statements regarding the primitive streak is INCORRECT?
It marks the beginning of gastrulation.
It defines the embryo's axes.
It is the source of mesoderm and endoderm.
It persists throughout development.
A short-day plant is exposed to a flash of red light during the critical dark period. This is immediately followed by a flash of far-red light. What is the most likely outcome?
Flowering will be inhibited.
Flowering will be promoted.
The plant will become a long-day plant.
The far-red light will have no effect.
A long-day plant with a critical dark period of 9 hours is grown under short-day conditions. Which treatment is MOST LIKELY to induce flowering?
Increasing the ambient temperature during the dark period.
Spraying the plant with gibberellins during the light period.
Interrupting the dark period with a brief exposure to red light.
Exposing the plant to far-red light at the end of the dark period.
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
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.
A seedling is placed horizontally on a rotating platform in the dark. Which of the following best describes the growth pattern of the seedling's root and shoot after a few days?
Both root and shoot will grow horizontally.
The root will grow upwards, and the shoot will grow downwards.
The root will grow downwards, and the shoot will grow upwards.
Both root and shoot will grow in a random direction.
A scientist is culturing leaf mesophyll cells. The cells lose their specialized features and form an unorganized mass. This is NOT an example of:
Dedifferentiation
Callus formation
Cellular totipotency
Differentiation
