Biology, Eighth Edition (Raven)

Chapter 24: Genome Evolution

Control of Gene Expression in Eukaryotes

What is meant by gene expression? Gene expression refers to genes being ‘turned on’ and producing a product. The product could be an enzyme, a structural protein, or a control molecule. Studies of gene expression typically measure the production of mRNA. Most mechanisms that control gene expression do so by controlling transcription, the synthesis of mRNA. However there are other mechanisms for controlling the rate of protein synthesis that occur downstream (between transcription and translation). Several of these are described in this animation.

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


1.	RNA polymerase binds to the

		A)	operator.
		B)	promoter.
		C)	regulator.
		D)	terminator.
		E)	enhancer.

2.	The most efficient control of eukaryotic gene expression is achieved at the level of

		A)	replication.
		B)	transcription initiation.
		C)	post-transcription.
		D)	translation initiation.
		E)	post-translation.

3.	At which of the following level(s) can gene expression be regulated in eukaryotes?

		A)	passage of mRNA through the nuclear membrane
		B)	destruction of the mRNA
		C)	rate of protein synthesis
		D)	A and B
		E)	A, B and C

4.	The addition of a phosphate to a protein after it is produced is an example of post-transcriptional modification.

		A)	True
		B)	False

5.	The exons of eukaryotic mRNA are removed and the introns are spliced together.

		A)	True
		B)	False