Transcription and RNA Processing - AP Biology
- What is RNA processing?
- Modifications of pre-mRNA to mature mRNA. These modifications prepare mRNA for translation and nuclear export.
- What is the role of silencers in transcription?
- Decrease transcription levels. These regulatory sequences reduce gene expression when bound by repressors.
- What are operons?
- Clusters of genes under single promoter in prokaryotes. This organization allows coordinated expression of related genes.
- Identify the role of the terminator sequence in transcription.
- Signals end of transcription. This sequence causes RNA polymerase to stop and release the transcript.
- Which enzyme is primarily responsible for transcription?
- RNA polymerase. This enzyme reads DNA template and assembles RNA nucleotides into a strand.
- What are introns?
- Non-coding sequences in mRNA. These sequences are spliced out during mRNA processing.
- Identify the process of mRNA export from nucleus.
- Nuclear export. This transport mechanism moves processed mRNA to cytoplasm for translation.
- What is the purpose of the 5' cap?
- Protects mRNA from degradation. Prevents 5' exonuclease digestion and facilitates ribosome binding.
- What is the role of enhancers in transcription?
- Increase transcription levels. These regulatory sequences boost gene expression when bound by activators.
- What is a transcription factor?
- Protein that regulates transcription. These regulatory proteins control gene expression by binding DNA.
- Identify the process that converts a gene into mRNA.
- Transcription. This is the first step in gene expression, creating RNA from DNA.
- Which modification is added to the 5' end of eukaryotic mRNA?
- 5' cap. This modified guanosine structure protects mRNA from degradation.
- What is alternative splicing?
- Production of different mRNA from the same transcript. This mechanism creates protein diversity by varying exon combinations.
- What is transcription initiation complex?
- Assemblage of transcription factors and RNA polymerase. This complex forms at promoters to begin RNA synthesis.
- Which RNA molecule carries amino acids to ribosomes?
- Transfer RNA (tRNA). These molecules have specific anticodons that match with mRNA codons.
- What is the main purpose of transcription in cells?
- To synthesize RNA from a DNA template. This process creates RNA copies of genetic information for protein synthesis.
- What occurs during the elongation phase of transcription?
- RNA polymerase synthesizes RNA strand. The polymerase moves along DNA, adding complementary RNA nucleotides.
- Which type of RNA is involved in protein synthesis?
- Ribosomal RNA (rRNA). This RNA forms the structural and catalytic core of ribosomes.
- What is the template strand in transcription?
- DNA strand used to synthesize RNA. This antisense strand provides the pattern for complementary RNA synthesis.
- What is the primary transcript in eukaryotic cells?
- Pre-mRNA. This unprocessed RNA transcript contains both exons and introns.
- Identify the enzyme that adds the poly-A tail.
- Poly-A polymerase. This enzyme extends the 3' end with multiple adenine nucleotides.
- What is the role of snRNPs in RNA processing?
- Participate in splicing by forming spliceosome. Small nuclear ribonucleoproteins recognize splice sites and catalyze splicing.
- Which RNA base pairs with adenine in DNA?
- Uracil. RNA uses uracil instead of thymine for base pairing with adenine.
- What is the role of ribonuclease in RNA processing?
- Degrades RNA molecules. These enzymes cleave RNA during processing and quality control.
- Which complex is responsible for RNA splicing?
- Spliceosome. This ribonucleoprotein complex precisely cuts out intron sequences.
- Identify the enzyme that synthesizes the 5' cap.
- Capping enzyme. This enzyme adds the protective 7-methylguanosine cap structure.
- What is the function of mRNA?
- Carries genetic information from DNA to ribosomes. Acts as an intermediate messenger between genes and protein synthesis.
- Identify the enzyme that unwinds DNA during transcription.
- Helicase. This enzyme separates DNA strands to create the transcription bubble.
- Which molecule forms the core of the spliceosome?
- snRNA. Small nuclear RNA guides the splicing machinery to correct sites.
- Which process ensures mRNA is mature before translation?
- RNA processing. This quality control step removes introns and adds protective modifications.
- What stabilizes mRNA and assists in export to cytoplasm?
- Poly-A tail. Also enhances mRNA stability and facilitates nuclear export.
- What is the role of mediator proteins?
- Bridge between transcription factors and RNA polymerase. These proteins coordinate transcriptional regulation by connecting factors.
- What are exons?
- Coding sequences in mRNA. These sequences remain in mature mRNA and code for proteins.
- Which sequence signals the start of transcription?
- Promoter sequence. This regulatory sequence determines where transcription begins.