TABLE 2.

Student responses to questions from meiosis assessment

Questions	Students who answered correctly (N = 69)	To answer the question completely (and correctly), students must be able to:	Typical features of wrong answers
Q1. The figure at right represents a diploid precursor germ cell [chromosomes are unreplicated]. How many chromosomes are shown and what is the value of “N”?	26.1%	Link chromosomal and informational aspects of DNA to correctly identify ploidy of cells before and after DNA replication.	Students often rely on chromosome appearance rather than informational content in determining ploidy. Thus, they assume cells that contain two-DNA (replicated) chromosomes are diploid and cells that contain one-DNA (unreplicated) chromosomes are haploid.
Q2. The figure at right represents a diploid precursor germ cell [chromosomes are replicated]. How many chromosomes are shown and what is the value of “N”?	8.7%
Q3. Circle all haploid cells in the figure of meiosis below. [Figure shows a diploid cell before and after meiosis I and meiosis II]	4.3%
Q4. What is the difference between homologous pairs and sister chromatids?	13%	Link molecular and informational aspects of DNA to correctly differentiate between sister chromatids and homologous chromosomes.	Students rarely acknowledge the underlying sequence identity of sister chromatids or the nearly identical nature of the DNA sequences on homologous chromosomes.
Q6. How do homologous chromosomes find each other to pair properly?	4.35%	Link molecular and chromosomal concepts to correctly explain the underlying mechanism of homologous pairing and explain its importance to segregation in terms of information content.	Students rarely consider the underlying molecular mechanism and rarely acknowledge that DNA sequence (near) identity drives homologous pairing.
Q7. What determines where crossing over occurs?	1.45%
Q9. Is crossing over necessary for meiosis? Explain.	0%
Q11. How similar are X and Y chromosomes? Why is this important?	1.45%