AP Biology Gene Regulation

When DNA is compacted by histones into 10 nm and 30 nm fibers, the DNA is unable to interact with proteins required for gene expression. Therefore, to allow for these proteins to act, the chromatin must constantly alter its structure. Which processes contribute to this dynamic activity?

• methylation and phosphorylation of histone tails

• nucleotide excision and reconstruction

The tryptophan operon is a repressible operon that is

• turned off whenever tryptophan is added to the growth medium

• turned on only when glucose is present in the growth medium.

Altering patterns of gene expression in prokaryotes would most likely serve the organismʹs survival in which of the following ways?

• allowing the organism to adjust to changes in environmental conditions

• organizing gene expression so that genes are expressed in a given order

• allowing environmental changes to alter the prokaryoteʹs genome

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NGSS.HS-LS4-4

This can inhibit transcription by blocking the binding of positively acting transcription factors to the DNA:

• enhancer

• promoter

• repressor

A process of turning genes on and off.

• gene mutation

• gene regulation

• gene process

• gene replication

A lack of this nonprotein molecule would result in the inability of the cell to "turn off" genes:

• Operon

• Inducer

• Promoter

• Repressor

• Corepressor

In order for a gene to be expressed, ___ must bind to the gene's ___, a specific sequence of nucleotides at one end of the gene, thus initiating transcription.

• DNA polymerase, promotor

• DNA polymerase, operator

• RNA polymerase, promotor

• RNA polymerase, operator

When a gene is activated _________ binds to the DNA at the start of the gene and moves along the DNA to create mRNA

• keritanase

• RNA polymerase

• TAQ polymerase

• catalyase

A certain kind of butterflies produces red pigment in summer but blue in winter. This is probably due to...

• polymerase becoming ligase

• three or more copies of the same chromosomes

• regulation of gene expression

• new viruses in new locations

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NGSS.HS-LS4-4

The initial steps in gene expression are modeled. Double-stranded DNA first unwinds into two strands. Which process and product are represented in the diagrams?

• Process: transcription; product: mRNA

• Process: translation; product: protein

• Process: replication; product: tRNA

• Process: recombination; product: polymerase

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NGSS.HS-LS1-1