Biology, Eighth Edition (Raven)

Chapter 15: Genes and How They Work

RNA Splicing

What property of RNA and DNA allows for the cutting of the molecule and removing of pieces without destroying the entire structure? Both RNA and DNA are modular structures. They consist of repeated elements: sugars and bases. Each repeated element has a 3’ and a 5 ‘ end. These repeated elements link to one another in a chain, attaching the 3’ end of one molecule to the 5’ end of another molecule. If a section of the chain is removed the two separated sections will have exposed 3’ and 5’ ends. Thus the two separated sections can easily attach to one another and form a complete chain. The modular nature of DNA and RNA allow the molecules to be modified relatively easily when necessary.

View the animation below, then complete the quiz to test your knowledge of the concept.



1.

Splicing joins together
A)two introns.
B)two exons.
C)an intron and an exon.
D)any two RNA molecules.
E)a DNA and an RNA molecule.
2.

The snRNPs are also called
A)smurfs.
B)snurps.
C)snores.
D)snippets.
E)splits.
3.

Arrange the following in the proper sequence in which they occur during RNA splicing.

1. Lariat is formed
2. U2 binds to branch site
3. 3' splice site is cut
A)1, 2, 3
B)2, 1, 3
C)2, 3, 1
D)3, 2, 1
E)3, 1, 2
4.

The 3’ splice site contains a GU, whereas the 5’ splice site contains an AG.
A)True
B)False
5.

The trimer that binds at the intron region consists of the snRNPs U3, U4 and U5.
A)True
B)False
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