Weeks 5
The enzyme relieves torsional strain during DNA replication by creating a transient single-strand break in the DNA backbone.
What is DNA topoisomerase?
This general transcription factor has helicase activity and phosphorylates the C-terminal domain (CTD) of RNA polymerase II to promote promoter clearance.
What is TFIIH?
These small adaptor molecules match specific anticodons to mRNA codons during translation, ensuring that the correct amino acids are added to a growing polypeptide chain at the ribosome
What are transfer RNAs (tRNA)?
In this model of DNA replication, each daughter molecule contains one original strand and one newly synthesized strand
What is semiconservative replication?
The DNA repair mechanism fixes double-strand breaks by directly joining the broken ends without requiring a homologous template.
What is non-homologous end joining?
This RNA-processing event removes introns from a primary transcript and joins exons together to form a mature mRNA.
What is RNA splicing?
These chemical alterations to tRNA bases- such as methylation or the conversion of uridine to pseudouridine- help stabilize structure, improve codon recognition, and increase the fidelity of protein synthesis
What are tRNA modifications?
When the cellular machinary incorrectly removes introns or joins exons, this type of RNA processing mistake can product faulty proteins linked to mutations
What are splicing errors?
The enzyme synthesizes short RNA segments that provide a free 3'- OH group for DNA polymerase to begin replication.
What is DNA primase?
This RNA-protein complex recognizes the 5' splice site during the early stages of spliceosome assembly.
What is U1 snRNP?
Aids in translocation of the small subunit to realign the E, P, and A sites so they are ready for binding of the next amino acylated tRNA. Also associated with GTP that is hydrolyzed to GDP during this process, helping to provide energy for the next step.
What is EF-G?
What is exonucleolytic proofreading?
The DNA repair system corrects errors that escape proofreading by recognizing distortions in the DNA helix and removing mismatches nucleotides.
What is strand-directed mismatch repair?
This RNA polymerase synthesizes most protein-coding genes in eukaryotic cells.
What is RNA polymerase II?
This cellular quality control pathway detects premature stop codons in mRNA transcripts and targets them for degradation, preventing the production of truncated potentially harmful proteins.
What is nonsense-mediated mRNA decay?
This eukaryotic process removes introns from a newly made RNA transcript and joins exons together, often using a spliceosome composed of snRNPs like U1 and U2
What is pre-mRNA splicing?
This Y shaped structure forms during DNA replication where parental strands separate and new daughter strands are synthesized
What is a replication fork?
This modification added to the 3' end of eukaryotic mRNA increases stability and promotes nuclear export and translation.
What is the poly-A tail?
Functions include recognizing misfolded proteins, preventing aggregation, promoting refolding of a protein, and targeting proteins for degradation.
What are the primary functions of molecular chaperones?
During translation initiation the mRNA carries the coding sequence, the initiator tRNA brings the first amino acid, ribosomal subunits assemble at the start codon, initiation factors are proteins that help the ribosome binding and start codon recognition
What are the key players in translation initiation and what do they do?