Chapter 14: Gene Regulation

RNA polymerase

Each operon has a single promoter region upstream from the protein- coding regions; the promoter is where ________ first binds to DNA before transcription begins.

Proteases

________ associated with proteasomes degrade the protein into short peptide fragments.

Transcriptional level control

________ is the most common way for the prokaryotic cell to regulate gene expression.

Proteins

________ targeted for destruction are covalently bonded to ubiquitin, which tags it for degradation in a proteasome, a large macromolecular structure.

Repressor protein

The ________ is synthesized in an active form that binds to the operator.

Epigenetic inheritance

________ is an important mechanism of gene regulation that involves changes in how a gene is expressed.

Certain regulatory mechanisms

________ increase the stability of mRNA, allowing more protein molecules to be synthesized before the mRNA is degraded.

Eukaryotic genes

________ are controlled by DNA- binding proteins called transcription factors.

amplification

In the process of gene ________, some cells selectively amplify genes by DNA replication.

DNA methylation patterns

Because ________ tend to be repeated in successive cell generations, they provide a mechanism for epigenetic inheritance.

Regulatory control

________ at all levels of gene expression allows cells to rapidly and reversibly respond to changing physiological conditions.

Transcription factor

Each ________ has a DNA- binding domain.

Operator

The ________ serves as the regulatory switch for transcriptional- level control of the operon.

Catabolite activator protein

________ binds to the promoter region, stimulating transcription by binding RNA polymerase tightly.

Constitutive genes

________ are neither inducible nor repressible; they are active at all times.

genetic mutation

A(n) ________ in pigs makes them develop more muscle tissue.

Multicellular eukaryotes

In almost all ________, the promoter contains an element called the TATA box that has a regulatory function and facilitates expression of the gene.

Posttranslational control of eukaryotic genes

________ occurs by feedback inhibition or by chemical modifications that change the proteins structure.

Cap

To bind, ________ requires cyclic AMP (cAMP), which increases in the cell as glucose decreases.

Bacterial cells

________ grow rapidly and have a relatively short lifespan.

Metabolite

A(n) ________ (usually the end product of a metabolic pathway) acts as a corepressor.

inducible operon

A(n) ________, such as the lac operon, is normally turned off.

Corepressor levels

When ________ are high, a corepressor molecule binds to the repressor, which can now bind to the operator and turn off transcription of the operon.

Methyl groups

________, acetyl groups, sugars, and proteins may chemically attach to the histone tail, a string of amino acids that extends from the DNA- wrapped nucleosome, and may expose or hide genes, turning them on or off.

Active genes

________ are associated with a loosely packed chromatin structure called euchromatin.

repressor protein

The ________ is synthesized in an inactive form that can not bind to the operator.

Eukaryotic genes

________ are not normally organized into operons.

transcription factors

Some ________ are** leucine zipper proteins** that associate as dimers that insert into the DNA.

transcription factors

Some ________ have a helix- turn- helix arrangement and insert one of the helices into the DNA.

repressor protein

The binding of a(n) ________ to the operator sequence prevents transcription; although RNA polymerase binds to the promoter, it is blocked from transcribing the structural genes.

eukaryotic genes

Some ________ have enhancers and silencers located thousands of bases away from the promoter.

repressor protein

When the ________ binds to the operator, transcription of the operon is turned off.

repressor protein

If lactose is present, it is converted to allolactose, the inducer, which binds to the ________.