Transcription
Where does transcription occur in the cell for prokaryotes? In eukaryotes?
Prokaryotes: Cytoplasm
Eukaryotes: Nucleus
What are the start and stop codons?
Start: AUG
Stop: UAA, UAG, and UGA
How many strands make up RNA
One
Which subunit of ribosomes bind to the mRNA first?
Small subunit
What is the purpose of tRNA?
It is an adaptor molecule that carries the amino acid to the ribosome and whose anticodon hydrogen bonds to the codon on the mRNA.
What is the intron called when it folds and cleaves off during RNA splicing?
Lariat
Amino acid activation is mediated by which enzyme?
Aminoacyl-tRNA Synthetase
How many RNA polymerases are required for transcription in bacteria?
One
Which binding site is the tRNA sent to on the ribosome when the amino acid attached has been transferred to the incoming tRNA
E site (Exit site)
What is required for tRNA synthetase to catalyze a reaction?
ATP
In prokaryotes, how is RNA synthesis terminated?
Hairpin or Rho protein termination
Why do multiple codons code for the same amino acid?
(Codons are redundant) It is believed that errors are more prevalent in the third position and redundancy evolved as some form of 'protection' to decrease mutation rates since RNA has less fidelity than DNA.
Type of RNA in which codes for proteins
mRNA (Messenger RNA)
How many binding sites do ribosomes have for mRNA?
One
Why is it 'okay' or 'more tolerated' for RNA synthesis to have less fidelity than DNA replication?
RNA does not store genetic information
DNA preserves genetic integrity
What is used to relieve helical tension during transcription in prokaryotes?
Gyrase
What is the name of the loop in tRNA in which determines the amino acid that is attached.
Anticodon loop
What is the main difference between the core enzyme and the holoenzyme in reference to RNA polymerase?
The holoenzyme contains the promoter recognition subunit (sigma).
RNA which interferes with gene expression
siRNA (Small interfering RNA)
What is the region in which prokaryotes contain the 'start signal' for translation?
Shine-Delgarno sequence AKA Purine-rich region AKA -10 position
How does RNA polymerase transcribe DNA that is wound around tightly packed chromatin?
Utilizing histone-modifying proteins
Why is it possible to fit the 20 amino acids to their 61 codons with as few as 31 different kinds of tRNA molecules? (In bacteria)
Wobble base-pairing
Why is it that prokaryotes have no need of processing or export during transcription and translation?
These processes both occur in the cytoplasm
___ binds to the A site of the large ribosomal subunit to facilitate termination
Release factor
During the discussion in lecture, we discussed mad cow disease. Why is it not possible to cure mad cow disease?
Caused by protein prions which cause other normal proteins to misfold.
Not necessarily a 'foreign material' that the body can recognize and target.