C. Eukaryotic genes often contain introns while prokaryotic genes do not.
Clarify Question
· What is the key concept addressed by the question?
o This question addresses transcription and translation.
· What type of thinking is required?
o This question is asking you to analyze the information given, using logic, to dissect the problem and determine the answer.
· What key words does the question contain and what do they mean?
o A eukaryotic cell is from an organism with a nucleus, like a human, fly, plant, or fungus.
o A prokaryotic cell is a single-celled organism such as a bacterium like E. coli.
Gather Content
· What do you already know about transcription and translation?
o There are some key differences in transcription and translation between eukaryotes and prokaryotes.
o One of the main differences is that eukaryotic genes typically have introns, which are spliced out of the pre-mRNA by specialized splicing machinery. Prokaryotes do not have introns or the machinery to splice them out.
Consider Possibilities
· Consider the different answer options. Which can you rule out?
o Could the different RNA polymerases explain the change in the protein? No, that doesn’t make sense.
o Could the 5’ cap explain the change in the protein? No, because that affects stability but not the sequence of the protein itself.
Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
o The best explanation is that the eukaryotic gene contained introns. In a prokaryote they would not be removed, so the protein would have extra sections of translated sequence.
o For this reason, scientists usually use a cDNA, or complementary DNA copy from a processed mRNA, rather than the DNA gene itself when they clone a eukaryotic gene into bacteria for protein expression.
Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result? o This question asked why a eukaryotic gene would not produce the same protein in a prokaryote.
o The question required you to analyze the information given, using logic, to dissect the problem and determine the answer.
o Did you recognize that prokaryotes lack the splicing machinery?