TABLE 6.

Conceptual difficulties identified in student responses

Process	Conceptual difficulties
Replication	Stop codon stops replication, resulting in a shorter DNA strand.
	A shorter DNA strand results in a shortened mRNA strand and a shorten protein.
Transcription	Stop codon stops transcription and results in a shorter mRNA strand.
Translation	Translation does not take place when a stop codon is present.
	Translation does not stop when a stop codon is present, yet a shorter protein is produced.
	No protein would be produced.
	Fewer proteins would be produced during translation when a stop codon is present.