Gene Regulatory

Of the three modes of gene regulation shown in Figure 18.1, which is the fastest in response time? Post-translational control Transcriptional control Translational control All three are equally fast.

Of the three modes of gene regulation shown in Figure 18.1, which is the most efficient in resource use? Post-translational control Translational control. Transcriptional control All three are equally efficient.

At which of the following stages does transcriptional control occur? a b c DNA ——> mRNA ——> protein ——> activated protein

Which of the following statements about gene expression is true? The control of gene expression is most like the control of a light using an on/off switch. The expression of all genes is regulated in response to changing environments. Gene expression only needs to be controlled for a small set of genes. Gene expression only needs to be controlled in bacteria. The control of gene expression is most like the control of a light using a dimmer switch.

Although the expression of most genes is tightly regulated, some genes are expressed at roughly constant rates. Which of the following genes would you predict to be constitutively (constantly) expressed? genes involved in the biosynthesis of the amino acid tryptophan genes that code for regulatory proteins genes involved in the degradation of arabinose, a sugar genes involved in the degradation of tryptophan

The greatest expression of the lac operon occurs when lactose levels are _____. low and glucose levels are high low and glucose levels are low high and glucose levels are high high and glucose levels are low

Altering patterns of gene expression in prokaryotes would most likely serve an organism's survival by _____. allowing environmental changes to alter a prokaryote's genome allowing an organism to adjust to changes in environmental conditions organizing gene expression, so that genes are expressed in a given order allowing each gene to be expressed an equal number of times allowing young organisms to respond differently than more mature organisms

Which of the following, when taken up by a cell, binds to a repressor so that the repressor no longer binds to the operator? ubiquitin inducer repressor corepressor promoter

Negative control & Positive control

What is the role of lactose in regulating lac operon expression? It induces translation by binding to the repressor and removing it from the mRNA. It induces transcription by binding to the repressor and causing its release from the operator. It induces transcription by binding directly to the promoter and attracting RNA Polymerase. It represses transcription by binding to the repressor.

An operon is ______. a bacterial gene that is controlled by a promoter a DNA sequence that is recognized by the repressor protein a form of operator that is under negative regulation a set of bacterial genes that are regulated together and transcribed into a single RNA a form of operator that is under positive regulation

Allosteric regulation occurs when ______. a repressor binds to an operator RNA polymerase cannot initiate transcription at a promoter a regulatory molecule binds to a protein to change its shape and activity the sigma factor associated with RNA polymerase binds to the promoter the promoter separates from the DNA

The lac repressor protein binds to the operator when it is ______. bound to glucose not bound to glucose not bound to lactose bound to arabinose bound to lactose

Which of the following leads to the highest rate of lac operon transcription? intermediate levels of lactose and glucose high lactose levels and low glucose levels high lactose levels and high glucose levels low lactose levels and high glucose levels low lactose levels and low glucose levels

In negative control, a gene is switched off when _____. a kinase adds a phosphate to DNA a regulatory protein is removed from DNA and shuts down transcription a regulatory protein binds to DNA and shuts down transcription lactose is transported into the cell

Suppose several genes are grouped together in a genome and the group results in a single enzyme. If one of these genes is mutated and the enzyme is no longer active, this gene must be part of _____. a repressor an intron an inducer an activator an operon

According to the lac operon model proposed by Jacob and Monod, what is predicted to occur if the operator is removed from the operon? The lac operon would be transcribed continuously. Only lacY would be transcribed. Only lacZ would be transcribed. Galactosidase permease would be produced, but would be incapable of transporting lactose.

The product of the lacI gene is _____. a transport protein embedded within the membrane the repressor β-galactosidase an enzyme

Most repressor proteins are allosteric. Which of the following binds with the repressor to alter its conformation? inducer cAMP promoter transcription factor RNA polymerase

Regarding regulation of the ara operon, what would be the effect of a mutation that removes the part of the AraC protein that binds to RNA Polymerase? Transcription would occur at high levels in both the presence and absence of arabinose. Transcription would occur at high levels in the presence, but not the absence, of arabinose. Transcription would not occur at high levels in either the presence or absence of arabinose. Transcription would occur at high levels in the absence, but not the presence, of arabinose.

Which of the following is the protein that positively regulates transcription of the ara operon? arabinose AraC the ara operator glucose the lac repressor

An important difference between the ways that bacteria and multicellular eukaryotes regulate gene expression is that ______. multicellular eukaryotes need to respond to signals from other cells much more than do bacteria bacteria make little use of transcriptional regulation multicellular eukaryotes only respond to signals from their external environment bacteria make much more use of signals inside their cells

Which answer best explains how certain patterns of histone acetylation or DNA methylation could influence whether a cell became a muscle cell or a brain cell? They could produce different patterns of post-translational control in different cell types. They could affect which sets of genes are transcribed in different cell types. They could produce differences in the DNA sequences of genes found in different cell types. They could determine what sets of genes are found in different cell types.

Why do histones bind tightly to DNA? Histones are highly hydrophobic, and DNA is hydrophilic. Histones are covalently linked to the DNA. Both histones and DNA are strongly hydrophobic. Histones are negatively charged, and DNA is positively charged. Histones are positively charged, and DNA is negatively charged.

_____ bind(s) to DNA enhancer regions. RNA polymerase Promoters Introns Activators Exons

Differential gene expression is the result of different cells containing different ______. regulatory proteins nucleosomes regulatory sequences genes

An example of a basal transcription factor is _____. a promoter-proximal-binding transcription factor a silencer-binding transcription factor RNA polymerase an enhancer-binding transcription factor the TATA-binding protein

Regulatory transcription factors _____. influence the degree of unwinding of DNA at the promoter influence the assembly of the basal transcription complex open the two strands of DNA so that RNA polymerase can begin transcription influence the binding of sigma factor to DN

Alternative RNA splicing _____. increases the rate of transcription is due to the presence or absence of particular snRNPs can allow the production of similar proteins from different RNAs can allow the production of proteins of different sizes and functions from a single mRNA is a mechanism for increasing the rate of transcriptio