Regulation of Gene Transcription - AP Biology
- Identify the process where small RNAs regulate gene expression post-transcriptionally.
- RNA interference. Uses small RNAs to silence target genes.
- Identify the region where transcription terminates in prokaryotes.
- Terminator sequence. Signals the end of transcription in bacteria.
- Which molecule can prevent transcription in an operon by binding to the operator?
- Repressor. Blocks transcription when bound to operator.
- What is the primary structure that RNA polymerase binds to initiate transcription?
- Promoter. Essential regulatory region for transcription start.
- Identify the enzyme that synthesizes RNA during transcription.
- RNA polymerase. The primary enzyme responsible for RNA synthesis.
- Which RNA polymerase is responsible for rRNA synthesis in eukaryotes?
- RNA polymerase I. Produces ribosomal RNA in the nucleolus.
- What is the function of RNA polymerase III in eukaryotes?
- Transcribes tRNA and some small RNAs. Synthesizes transfer RNA and regulatory RNAs.
- What determines the strength of a promoter in gene transcription?
- Affinity for transcription factors and RNA polymerase. Binding efficiency determines transcription frequency.
- Define an operon.
- A cluster of genes regulated together. Found in prokaryotes for coordinated gene control.
- Identify the effect of histone deacetylation on transcription.
- Decreases transcription by tightening DNA-histone interaction. Compacts chromatin, reducing gene accessibility.
- Which process involves the removal of introns from pre-mRNA?
- RNA splicing. Removes non-coding sequences from pre-mRNA.
- Identify the role of general transcription factors in eukaryotes.
- Assist in forming the transcription initiation complex. Required for RNA polymerase binding and function.
- What is the function of an enhancer in transcription regulation?
- Increases transcription levels by interacting with activators. DNA sequences that boost gene expression remotely.
- Identify the role of histone acetylation in gene transcription.
- Increases transcription by loosening DNA-histone interaction. Opens chromatin structure for gene accessibility.
- Which molecule acts as an inducer in the lac operon?
- Allolactose. Derived from lactose, activates the lac operon.
- What is the function of a silencer in gene regulation?
- Decreases transcription by binding repressor proteins. Regulatory elements that reduce gene expression.
- What is the main purpose of transcriptional activators?
- Increase transcription by binding to enhancers. Promote gene expression by recruiting RNA polymerase.
- What is the primary role of the mediator complex in transcription?
- Facilitates interaction between transcription factors and RNA polymerase. Bridges regulatory proteins with transcription machinery.
- What is the purpose of alternative splicing?
- Generates different mRNA variants from the same gene. Increases protein diversity from a single gene.
- Which process can silence genes via RNA-induced silencing complex (RISC)?
- RNA interference. Post-transcriptional gene silencing mechanism.
- What is the function of the TATA box in eukaryotic promoters?
- Indicates where transcription starts by binding transcription factors. Core promoter element crucial for transcription initiation.
- What is the consequence of a mutation in the TATA box?
- Altered gene expression due to faulty transcription initiation. Disrupts normal transcription factor binding.
- Identify the role of a repressor protein in transcription.
- Binds to operators to block RNA polymerase. Prevents transcription when bound to operator sequences.
- Which factor is crucial for the termination of transcription in bacteria?
- Rho factor. Protein-dependent transcription termination mechanism.
- Which type of RNA is synthesized from DNA during transcription?
- mRNA, tRNA, and rRNA. All RNA types produced during transcription.
- Which RNA polymerase transcribes mRNA in eukaryotes?
- RNA polymerase II. Specifically synthesizes messenger RNA transcripts.
- What is the role of an operator in an operon system?
- Regulates transcription by interacting with repressors. DNA sequence that controls repressor binding.
- What is the role of a promoter region in gene transcription?
- Initiates transcription by binding RNA polymerase. Acts as the binding site where transcription begins.
- Which element is essential for transcription initiation in eukaryotes?
- Promoter. Required regulatory sequence for gene expression.
- What is the function of the 5' cap in mRNA?
- Protects mRNA from degradation and aids ribosome binding. Stabilizes mRNA and facilitates translation initiation.
- What does the sigma factor do in bacterial transcription?
- Guides RNA polymerase to the promoter. Helps RNA polymerase recognize specific promoters.
- Identify the protein that unwinds DNA for transcription initiation.
- Helicase. Separates DNA strands for RNA polymerase access.
- What is an example of a post-transcriptional modification?
- 5' capping or polyadenylation. RNA processing that occurs after transcription.
- Which chemical modification of DNA is associated with repression of transcription?
- DNA methylation. Silences genes by adding methyl groups to cytosine.
- Identify the role of coactivators in transcription regulation.
- Enhance transcription by linking activators to the transcription machinery. Bridge activators to the transcription complex.
- What occurs when a transcription factor binds an enhancer?
- Increases transcription by stabilizing the transcription complex. Enhances transcriptional machinery assembly.
- Which molecule is a transcription factor that regulates gene expression?
- Proteins that bind to DNA sequences. Regulatory proteins that control gene expression levels.