chapter 8 Flashcards
(41 cards)
What is a key structural difference between RNA and DNA?
RNA is typically a single-stranded molecule and contains ribose sugar instead of deoxyribose.
List the different classes of RNA found in a cell.
- Messenger RNA (mRNA)
- Transfer RNA (tRNA)
- Ribosomal RNA (rRNA)
- Small nuclear RNA (snRNA)
- MicroRNAs (miRNAs)
- Small interfering RNAs (siRNAs)
How is RNA polymerase positioned to start transcription?
RNA polymerase is recruited to a specific gene sequence known as the promoter.
What modifications occur to eukaryotic mRNA before it leaves the nucleus?
Eukaryotic mRNA undergoes capping, polyadenylation, and splicing.
Why is the discovery of self-splicing introns important?
It challenges the traditional view of gene expression and suggests that RNA can have catalytic functions.
What are non-protein-coding RNAs (ncRNAs)?
ncRNAs are RNA molecules that do not encode proteins but have regulatory roles.
True or False: More complex organisms have larger genomes with more genes.
False - Some complex organisms, like rice, have more genes than humans despite being less complex.
What is the central dogma of molecular biology?
The central dogma describes the flow of genetic information from DNA to RNA to protein.
What does the term ‘pulse-chase experiment’ refer to in RNA research?
It is a technique used to study the synthesis and degradation of RNA.
What is the role of ribozymes?
Ribozymes are RNA molecules that can catalyze biological reactions.
Fill in the blank: RNA nucleotides possess the bases adenine, cytosine, guanine, and ______.
uracil
What are the key stages of transcription?
- Initiation
- Elongation
- Termination
What is the function of promoters in transcription?
Promoters are sequences found upstream of the transcription initiation site that recruit RNA polymerase.
What is the difference between intrinsic and rho-dependent termination in transcription?
Intrinsic termination involves a hairpin structure in RNA, while rho-dependent termination requires the Rho protein to separate RNA from RNA polymerase.
What are the complications encountered in eukaryotic transcription?
- Identifying genes within vast genomes
- Separation of transcription and translation in time and space
- Packaging of DNA into chromatin
What is the difference between prokaryotic and eukaryotic RNA processing?
Prokaryotic RNA is translated immediately after transcription, while eukaryotic RNA must be processed before translation.
What is a 5’ untranslated region (5’ UTR)?
The region from the transcription initiation site to the start codon of translation.
What is a key complication encountered in eukaryotic transcription?
Must identify the genes to be transcribed within vast genomes.
In eukaryotes, how are transcription and translation separated?
Separated in time and space.
What is the TATA box?
A consensus sequence in promoter regions that is bound by TATA-binding protein (TBP).
What is the function of TATA-binding protein (TBP)?
It recruits other General Transcription Factors (GTFs) and RNA polymerase to the promoter region.
What forms the pre-initiation complex in eukaryotic transcription?
GTFs and RNA polymerase.
What triggers the initiation of transcription in eukaryotes?
Phosphorylation of the C-terminal domain (CTD) of RNA polymerase II.
What is cotranscriptional processing of RNA?
Modification of primary transcripts during elongation into mature mRNA.
