Exam 4 Review Part 2 Flashcards
Based on the amount of bases in the E. coli chromosome, it should take 40 minutes for the chromosome to replicate - so please explain why bacteria in a nutrient rich environment can replicate in 20 minutes
theta structure - can start the next round of replication before the previous round is complete
Most plasmids will replicate using the ___________ method which is a very different process than what is known for the chromosome replication
rolling circle
Compare Archaea, Bacteria, Eukarya: How many RNA polymerases?
B: 1
A: 1
E:3
Compare Archaea, Bacteria, Eukarya: how many subunits does the RNA polymerase have?
B: 4-5
A: 11-13
E: 12+
Compare Archaea, Bacteria, Eukarya: What finds the promoter for the RNA polymerase?
B: sigma factor
A: transcription factor
E: transcription factor
Compare Archaea, Bacteria, Eukarya: What protein can be involved in termination of transcription?
E; Termination factor
B. intrinsic method/ rhoprotein method
A: inverted repeats followed by AT rich DNA sequence, Eta termination protein
Is the following most likely true or false: the composition of the bacterial RNA polymerase is different between the initiation phase and most of the elongation phase of transcription. explain!
True - initiation requires a sigma factor, while elongation doesnt
bacterial promoters consist of a consensus sequence, TATAAT, located ____ (#) bases upstream of the bacterial transcription start site is called the __________. a second consensus sequence ________ is located ____ (#) bases upstream of the bacterial transcription start site
10
pribnow box
TTGACA
35
T/F: the average bacterial cell probably expresses over 1000 different sigma factors
False
Explain three similarities between DNA polymerase and RNA polymerase
- catalyze phosphodiester bonds by using nucleotide triphosphates
- move in 5’ to 3’ direction
- require templates
Explain three differences between DNA polymerase and RNA polymerase
- DNA polymerase requires a primer, RNA polymerase doesn’t (can start de novo)
- DNA polymerase has exonuclease activity
- DNA polymerase synthesize DNA, RNA polymerases synthesize RNA
- RNA polymerase does not require a promoter because of intrinsic helicase activity
In Bacteria, the intrinsic method for the termination of transcription involves two components found within DNA. The first is the presence of ______________ within the DNA which when transcribed within RNA forms a _______ structure pausing further movement of RNA polymerase. What is the second component and what relationship does this cause with the RNA?
inverted repeats
stem-loop
string of adenines, pair with uracil causing the weakest interactions following the stem-loop structure allowing for termination and separation of RNA polymerase
_________________ are the enzymes responsible for charging individual tRNA molecules with the appropriate amino acid. The amino acid is always added to the 3’ acceptor site consisting of three unpaired nucleotides with the sequence of __________
aminoacyl-tRNA synthetases
CCA
T/F: 5.8S rRNA is found only in the large ribosomal subunit of prokaryotes
False
Please explain why a chemical that binds to the 3’ end of 16S rRNA would be a good antimicrobial agent? Would there be any cross-reactivity with eukaryotic cells?
It would block the Shine-dalgarno sequence from pairing, thus there would be no start codon for recognition by tRNA. No, the binding site is distinct from that of eukaryotic cells