RNA Synthesis

What does mRNA do?

Codes for proteins

What does rRNA do?

Forms ribosome structure and catalyzes protein synthesis

What does tRNA do?

Transfers amino acids to ribosome; matches codons with anticodons

What does snRNA do?

Functions in splicing of pre-mRNA

What enzyme catalyzes transcription?

RNA polymerase

What strand serves as the template for transcription?

Antisense (noncoding) strand

What is a promoter?

DNA sequence upstream of transcription start site that recruits RNA polymerase

What is the TATA box?

Core promoter element that helps initiate transcription

What is the sigma factor? Sigmas lead to promote!)

Prokaryotic protein that guides RNA polymerase to the promoter

What is processivity?

Ability of RNA polymerase to remain bound and transcribe efficiently

What is rho-dependent termination?

Rho protein binds RNA and causes dissociation of RNA polymerase

What is rho-independent termination?

GC-rich palindrome forms hairpin loop followed by U-rich region 

What does RNA polymerase I transcribe?

rRNA genes (5.8S, 18S, 28S)

What does RNA polymerase II transcribe?

All protein-coding genes, miRNA, most snRNA

What does RNA polymerase III transcribe?

tRNA, 5S rRNA, some snRNA and small RNAs

What is the role of the CTD tail of RNA pol II?

Coordinates mRNA processing (capping, splicing, polyadenylation)

What happens during 5' capping?

Phosphate removed, GMP added, GMP methylated

What is the purpose of 5' capping?

Stabilizes mRNA and marks it as complete

What mediates mRNA splicing?

snRNPs (small nuclear ribonucleoproteins)

What is alternative splicing?

Selective exon inclusion to generate protein diversity

What does the poly-A tail do?

Stabilizes mRNA and aids in nuclear export

What enzyme adds the poly-A tail?

Poly-A polymerase (PAP)

What does rifampicin do?

Inhibits bacterial RNA polymerase (no proliferation/replication); used to treat tuberculosis

What does α-amanitin do? (a mushroom tin)

Inhibits eukaryotic RNA polymerase II; found in toxic mushrooms

What disease is caused by splice-site mutations in β-globin?

β-thalassemia

What disease affects snRNP assembly and causes hypotonia?

Spinal muscular atrophy (SMA)