Introns Out!
"Anything found to be true of E. coli must also be true of elephants."
Jacques Monod, 1965 Nobel laureate for the discovery of bacterial operons
Activity Description :
Students examine electron microscopy images of RNA-DNA hybridization and use colored yarn models to uncover how RNA tails led to the discovery of introns (noncoding segments of DNA) versus exons (coding segments of DNA).
DURATION : 30 minutes
SUBJECT AREAS : AP Biology and Biotechnology Pathways
KEY CONCEPTS : Split genes, RNA splicing, RNA processing
LEARNING OBJECTIVES : Students will be able to distinguish introns from exons. Students will be able to model RNA processing (5’ capping, 3’ polyadenylation, and splicing).
BACKGROUND KNOWLEDGE NEEDED : Protein synthesis — The process by which cells create proteins, consisting of transcription (DNA to RNA) and translation (RNA to protein).
STANDARDS ALIGNMENT :
NGSS High School Biology HS-LS1-1: Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins, which carry out the essential functions of life.
AP Biology Essential Knowledge 6.3.A.4: In eukaryotic cells, the mRNA transcript undergoes a series of enzyme-mediated modifications.
i. The addition of a poly-A tail makes mRNA more stable.
ii. The addition of a GTP cap helps with ribosomal recognition.
iii. The excision of introns, along with the splicing and retention of exons, generates different versions of the resulting mature mRNA molecule. This process is known as alternative splicing.
NOTE : This activity can be used alone or paired with Splice of Life! and Shhh! RNAi
Activity Resources :
Video Reference :
Two ways to watch
This film is available in two versions: an 84-minute television cut, free to stream on PBS and the PBS App, and a 97-minute director's cut, available on Hoopla and Kanopy or by request from Uncommon Productions.
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