Difficulty: Easy
Correct Answer: is equal to diploid cell
Explanation:
Introduction / Context:
Dikaryotic stages are hallmark features of many fungi, especially basidiomycetes (mushrooms). Understanding how n + n compares to 2n clarifies genetic states, nuclear behavior, and when karyogamy occurs during reproduction.
Given Data / Assumptions:
Concept / Approach:
An n + n cell physically contains two haploid nuclei. Counting total chromosome sets across both nuclei yields two sets in the cell, matching the total chromosome complement of a 2n nucleus. The key difference is nuclear organization (two separate n nuclei versus one fused 2n nucleus), not total chromosome set count.
Step-by-Step Solution:
Define dikaryon: two haploid nuclei per cell, maintained by clamp connections in many basidiomycetes.
Sum sets: n + n = 2n (as a cellular total), though physically separated.
Compare to diploid: a single nucleus with 2n has the same total sets.
Conclude equivalence in total chromosome sets, with different nuclear configurations.
Verification / Alternative check:
Cytological studies show delayed karyogamy; meiosis follows soon after nuclear fusion in basidia, confirming that the dikaryon precedes but does not equal a fused diploid nucleus.
Why Other Options Are Wrong:
Common Pitfalls:
Equating dikaryotic directly with diploid at the nuclear level; remember n + n has two nuclei, whereas 2n has one fused nucleus.
Final Answer:
is equal to diploid cell
Discussion & Comments