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Operon vocabulary Can you match terms related to operons to their definitions? Drag the terms on the left to the appropriate blanks on the right to complete the sentences.

Operon vocabulary

Can you match terms related to operons to their definitions?

Drag the terms on the left to the appropriate blanks on the right to complete the sentences.

The answer is :

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. Thegenes of an operonis/are arranged sequentially after the promoter.
3. A(n) promoter is a specific nucleotide sequence in DNA that binds RNA polymerase, positioning it to start transcribing RNA at the appropriate place.
4. A(n) regulatory genecodes for a protein, such as a repressor, that controls the transcription of another gene or group of genes.
5. Regulatory proteins bind to the operatorto control expression of the operon.
6. A(n) repressoris a protein that inhibits gene transcription. In prokaryotes, this protein binds to the DNA in or near the promoter.
7. A(n) inducer is a specific small molecule that binds to a bacterial regulatory protein and changes its shape so that it cannot bind to an operator, thus switching an operon on.

Regulation of model operons

The trp and lac operons are regulated in various ways.
How do bacteria regulate transcription of these operons?
operon is not transcribed
lac operon: lactose absent
trp operon: tryptophan present

operon is transcribed, but not sped up through positive control
lac operon: lactose present,
glucose present
trp operon: tryptophan absent

operon is transcribed quickly through positive control
lac operon: lactose present,
glucose absent

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