Download check understanding 13.4 gene regulation

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CHECK UNDERSTANDING 13.4
GENE REGULATION & EXPRESSION
Period _____ Date ______________ Seat ____
1. A tiny bacterium like E. coli contains more than 4000 genes. The bacterium does not
need all these genes to be active at the same time, so it turns many of them off until
needed. This method of switching genes on and off is known as gene
______________________________.
2. In prokaryotes, gene expression is often controlled by an _____________________,
which is a group of genes that are regulated together.
3. In E. coli, the lac operon controls the production of enzymes that breakdown the
milk sugar ___________________ into two simple sugars, glucose and galactose.
4. When lactose is not available as a food source, the lac genes are turned __________.
5. The Lac repressor gene makes repressor proteins that bind to the ______________.
6. The ___________________ region is where RNA polymerase first binds before it
begins transcribing the Lac genes into mRNA.
7. When lactose is _____________________, RNA polymerase cannot transcribe mRNA
because it cannot bind to the promoter region.
8. When available as a food source, lactose will bind to the ______________________
protein, enabling RNA polymerase to bind to the promoter and begin transcription.
9. In eukaryotes, ___________________________ factors help move RNA polymerase
into position so that transcription can take place.
10. In eukaryotes, the two regulatory regions that control gene expression are the
enhancer and the _______________ box.
11. In RNA interference, microRNA’s bind to proteins to form ______________________
complexes, which in turn are used to block gene expression.
12. All homeotic genes share a similar DNA sequence known as the _________________
sequence, which code for transcription factors that turn on other genes.
13. ____________ genes instruct cells how to differentiate during embryo development.
14. The electron micrograph below shows the process of translation in a prokaryote. In
the three boxes, write the names of the structures indicated. In addition, specify the
direction of translation and explain how you know. (7 points)