MBIO 218-Petkovich Lecture 10
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31 terms
Terms | Definitions |
|---|---|
 What molecular signal regulates the binding of a repressor or activator to the promoter? | effector |
| Repressors can be (activated/inactivated/both) by effectors. | both |
| What is the lacZ gene product? | beta-galactosidase |
| What is the lacY gene product? | galactosidase permease |
| What is the lacA gene product? | thiogalactosidase transacetylase |
| Which enzyme encoded by the lac operon modifies toxic galactosides that are imported into the cell along with lactose to facilitate removal from the cell? | thiogalactosidase transacetylase |
| What are the two main elements in the control of the lac operon? | repressor operator |
| What is the lacI gene product? | lac repressor |
| What is the lacO gene product? | lac operator |
| To which gene does the lac repressor bind? | lacO |
| Is the lacI gene (independent) of the lac operon or (encoded) by the lac operon? | independent (Re: p. 701) |
| True or false: In the absence of lactose, the lac genes are transcribed. | false |
| What is an example of an effector molecule that functions as an inducer of the lac operon? | allolactose |
| The lac operon contains 3 ribosome binding sites, it is therefore said to be ______________. | polycistronic |
| The lac repressor binds as a (monomer/dimer/trimer/tetramer) | dimer |
| The lac repressor binds to a(n) (inverted repeat element/direct repeat element). | inverted repeat element |
| The lac repressor binds to two distant sites on a DNA molecule and form a tetramer, creating a ____________. | DNA loop |
| A _________________ can be used to determine if a regulatory protein binds to DNA. | mobility shift assay |
| Binding a regulatory protein to DNA would cause (increased/decreased) migration of the DNA band in a mobility shift assay. | decreased |
| How many operons exist within the lacZ coding region? | 2 |
| How many operator sequences does the lac operon contain? | 3 |
| A DNA loop (enhances/blocks) promoter function. | blocks |
| How does the lac repressor bind to the DNA operator site? | helix-loop-helix interactions in major groove |
| This inducer alters the conformation of the DNA binding motif that facilitates binding of the lac repressor to DNA | IPTG (isopropylthiogalactoside) |
| When glucose is present, cAMP production in the cell is (enhanced/inhibited) and cAMP efflux from the cell is (induced/inhibited). | inhibited; induced |
| When glucose is high, cAMP is low and there is no lactose, gene expression (does/does not) occur. | does not |
| When glucose is low, cAMP is high and there is no lactose, gene expression (does/does not) occur | does not |
| When glucose is high, cAMP is low and lactose is present, gene expression (does/does not) occur. | does (low) |
| When glucose is low, cAMP is high and lactose is present, gene expression (does/does not) occur. | does (high) |
| Which factors associated with the RNA polymerase complex facilitates RNA polymerase binding to the promoter of the lac operon? | sigma |
| The activity of a genetic circuit is determined by the efficiency of RNA polymerase __________________. | recruitment |
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