Before You Begin
Question #45258
The Question
In Citrus and Mangifera, seeds often contain multiple embryos. If a maternal leaf cell of such a plant has 40 chromosomes and a DNA content of 2C in the G1 phase, which of the following statements regarding its adventive (nucellar) embryos is CORRECT?
Options
- A.
They arise directly from the diploid nucellus, bypassing the meiotic 4C to 1C DNA reduction, yielding clones with 40 chromosomes and 2C DNA content in G1.
- B.
They develop from an unreduced diploid egg cell (2n=40, 2C) formed without meiosis, representing a type of apomixis called diplospory.
- C.
They are formed by the fertilization of synergids or antipodals, followed by endoreduplication to achieve the 2n=40, 2C state.
- D.
They possess 40 chromosomes and 4C DNA content in their resting state (G0) because they bypass the anaphase-II separation of sister chromatids.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Sexual Reproduction in Flowering Plants|Polyembryony|Mitosis
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between different mechanisms of apomixis (sporophytic budding vs. unreduced egg development) and tracking DNA content (C-value) versus ploidy (n-value).
Students often confuse nucellar embryony with diplospory or fail to recognize that resting somatic cells maintain a 2C DNA content.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Cell Cycle and Cell Division - Class 11 |
| Concept | DNA vs Chromosome Content |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |