Chapter 18 Mastering Biology Test Questions – Flashcards

1. A(n) (operonis) a stretch of DNA consisting of an operator, a promoter, and genes for a related set of proteins, usually making up an entire metabolic pathway. 2. The (genes of an operon) is/are arranged sequentially after the promoter. 3. A(n) (promoteris) a specific nucleotide sequence inDNA that binds RNA polymerase, positioningit to start transcribing RNA at the appropriateplace. 4. A(n) (regulatory genecodes) for a protein,such as a repressor, that controls thetranscription of another gene or group ofgenes. 5. Regulatory proteins bind to the (operator) to control expression of the operon. 6. A(n) (repressoris) a protein that inhibits gene transcription.In prokaryotes, this protein binds tothe DNA in or near the promoter. 7. A(n) (inducer)is a specific small molecule that binds toa bacterial regulatory protein and changes its shape so that it cannot bind to anoperator, thus switching an operon on.

-Operon is not transcribed: trp operon tryptophan present. lac operon lactose abset -operon is transcribed, but not sped up through positive control: lac operon lactose present, glucose present trp operon tryptophan abset -operon is transcribed quickly through positive control: lac operon lactose persent, glucose absent

-Methylation of histone tails in chromatin can promote condensation of the chromatin. -Acetylation of histone tails in chromatin allows access to DNA for transcription. -Some forms of chromatin modification can be passed on to future generations of cells. -Acetylation of histone tails is a reversible process. -DNA is not transcribed when chromatin is packaged tightly in a condensed form.

-Control elements C, D, and E are distal control elements for the imaginin gene. -The fantasin gene will be transcribed at a high level when activators specific for control elements A, B, and C are present in the cell. -Both the fantasin gene and the imaginin gene will be transcribed at high levels when activators specific for control elements A, B, C, D, and E are present in the cell.