Review the animation and answer the questions that follow to test your understanding.
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1 | ![](/olcweb/styles/shared/spacer.gif) | ![](/olcweb/styles/shared/spacer.gif) When glucose is present |
| ![](/olcweb/styles/shared/spacer.gif) | A)![](/olcweb/styles/shared/spacer.gif) | cyclic AMP is high, the catabolite activator protein (CAP) binds to the activator binding site, and transcription of lactose is turned on |
| ![](/olcweb/styles/shared/spacer.gif) | B)![](/olcweb/styles/shared/spacer.gif) | cyclic AMP is low, CAP binds to the site activator binding site, and transcription of lactose is turned on |
| ![](/olcweb/styles/shared/spacer.gif) | C)![](/olcweb/styles/shared/spacer.gif) | cyclic AMP is high, CAP does not bind to the activator binding site, and transcription of lactose is turned on |
| ![](/olcweb/styles/shared/spacer.gif) | D)![](/olcweb/styles/shared/spacer.gif) | cyclic AMP is low, CAP does not bind to the activator binding site, and transcription is turned off |
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2 | ![](/olcweb/styles/shared/spacer.gif) | ![](/olcweb/styles/shared/spacer.gif) The lac repressor |
| ![](/olcweb/styles/shared/spacer.gif) | A)![](/olcweb/styles/shared/spacer.gif) | binds to the operator and prevents transcription |
| ![](/olcweb/styles/shared/spacer.gif) | B)![](/olcweb/styles/shared/spacer.gif) | binds to the CAP site and prevents transcription |
| ![](/olcweb/styles/shared/spacer.gif) | C)![](/olcweb/styles/shared/spacer.gif) | binds to the CAP site and facilitates transcription |
| ![](/olcweb/styles/shared/spacer.gif) | D)![](/olcweb/styles/shared/spacer.gif) | binds to the operator and facilitates transcription |
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3 | ![](/olcweb/styles/shared/spacer.gif) | ![](/olcweb/styles/shared/spacer.gif) When both glucose and lactose are present |
| ![](/olcweb/styles/shared/spacer.gif) | A)![](/olcweb/styles/shared/spacer.gif) | cyclic AMP is high so transcription occurs |
| ![](/olcweb/styles/shared/spacer.gif) | B)![](/olcweb/styles/shared/spacer.gif) | the lac repressor binds with the lactose and transcription occurs |
| ![](/olcweb/styles/shared/spacer.gif) | C)![](/olcweb/styles/shared/spacer.gif) | RNA polymerase is able to bind to the operator so transcription occurs |
| ![](/olcweb/styles/shared/spacer.gif) | D)![](/olcweb/styles/shared/spacer.gif) | transcription is turned off |
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4 | ![](/olcweb/styles/shared/spacer.gif) | ![](/olcweb/styles/shared/spacer.gif) In the absence of glucose, when lactose is present it combines with the repressor, allowing RNA polymerase to carry on transcription. |
| ![](/olcweb/styles/shared/spacer.gif) | A)![](/olcweb/styles/shared/spacer.gif) | True |
| ![](/olcweb/styles/shared/spacer.gif) | B)![](/olcweb/styles/shared/spacer.gif) | False |
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5 | ![](/olcweb/styles/shared/spacer.gif) | ![](/olcweb/styles/shared/spacer.gif) When both glucose and lactose are absent, transcription occurs. |
| ![](/olcweb/styles/shared/spacer.gif) | A)![](/olcweb/styles/shared/spacer.gif) | True |
| ![](/olcweb/styles/shared/spacer.gif) | B)![](/olcweb/styles/shared/spacer.gif) | False |
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