Gene Expression and Regulation
Post-transcriptional modifications in eukaryotes include splicing out introns; what is crucial for recognizing intron-exon boundaries accurately?
DNA helicases temporarily re-bind DNA strands post-RNA synthesis guiding snRNPs towards correct splicing sites via structural cues.
Small nuclear ribonucleoproteins (snRNPs) within spliceosomes facilitate precise intron removal and exon ligation processes.
Ribosomal subunits attach directly onto mRNA strands distinguishing exons from introns through base-pairing interactions.
Ligases perform proofreading functions distinguishing intronic sequences from exonic ones based on sequence conservation levels.
What could be a potential consequence if a point mutation resulted in a faulty spliceosome that is unable to recognize splice sites correctly?
Enhanced precision of exon selection improving protein function diversity.
No change in protein synthesis as alternative splicing compensates for errors.
Increased efficiency in pre-mRNA splicing resulting in faster maturation time.
Production of aberrant mRNA molecules leading to nonfunctional proteins or disease states.
The sequence of nucleotides on mRNA is read in triplets called __.
Introns
Exons
Codons
RNAs
What is responsible for recognizing and binding to promoter regions of DNA thus initiating transcription?
Transfer RNA (tRNA)
RNA polymerase II
Ribosomal subunits (rRNA)
Helicase enzymes
Which component is not directly involved in transcription initiation complex formation?
TATA binding protein (TBP)
Transcription factor IID (TFIID)
Ribosome subunits
General transcription factors
Transcribe the following sequence. G T A G T C
C A U C A G
C A T C A C
C A T C A G
C U T C U G
During eukaryotic pre-mRNA processing, what is added to the 5' end of an mRNA molecule?
A poly-A tail
A ribozyme sequence
An intron sequence
A modified guanine nucleotide cap

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An mRNA transcript must be modified in order to survive outside of the nucleus. In addition to a GTP cap, a transcript receives a(n) _____.
Intron cap
Exon tail
tRNA placeholder
Poly-A tail
Which of these processes occurs directly after pre-mRNA has been transcribed from DNA in eukaryotic cells?
Addition of a poly-A tail at the 3' end of pre-mRNA.
Translation into a polypeptide chain at ribosomes.
Replication of the pre-mRNA to form duplicate copies.
Methylation of adenines throughout the entire pre-mRNA molecule.
During phase elongation in prokaryotic organisms, what key factor ensures the sequential order of nucleotides being synthesized along the template strand?
Specificity of aminoacyl-tRNA synthetases towards their cognate tRNA molecules.
Availability of large pools of deoxyribonucleotide triphosphates near replication forks.
Action of topoisomerase enzymes relieving supercoiling tension ahead of the advancing polymerase.
Proofreading activity of RNA polymerases checking the newly incorporated base pairs.