Question 1
Question
How is the order of nucleotides in mRNA used to generate the linear sequences of amino acids in protein?
Answer
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process known as translation
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process know as transcription
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process know as post translational modifications
Question 2
Question
What process is the most highly conserved across all organism and the most energetically costly?
Answer
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translation
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transcription
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cellular respiration
Question 3
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Transcription is a more formidable challenge than translation.
Question 4
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The hydrophobic side chains of phenylalanine, tyrosine, and tryptophan forms interactions with the mRNA template.
Question 5
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Crick proposed a [blank_start]special adaptor[blank_end] molecule that directly interacts with the coding units of mRNA. He proposed to also be a [blank_start]RNA[blank_end] molecule.
Question 6
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amino acids that are attached to a class of RNA molecules that represent 15% of all celluar RNA and transfer amino acids to a growing polypeptide chain.
Question 7
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The translation machinery is comprised of ?
Question 8
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The competent of the translation machinery are always discarded after use.
Question 9
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Provides the information to be interpreted by translation machinery
Question 10
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This region of the mRNA specifies the order of amino acids by the ordered series of 3-nucleotide-long units called codons?
Answer
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introns
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poly A tail
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protein coding region
Question 11
Question
couple amino acids to specific tRNAs that recognize the appropriate codon?
Question 12
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coordinates correct recognition of mRNA by each tRNA and catalyzes peptide bond formation between growing peptide chain and amino acids attached to tRNA
Answer
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ribosomes
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ribozymes
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transferase
Question 13
Question
in mRNA containing 2 or more open reading frames that can encode for multiple polypeptide chains
Question 14
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protein coding regions of each mRNA is composed of contiguous, non-overlapping string of codons called?
Answer
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protein coding region
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origin of replication
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ORF
Question 15
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Eukaryotes, contain a single ORF that encode for multiple protein which is called polycistronic.
Question 16
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translation starts at the [blank_start]5'[blank_end] end of ORF and proceeds into the 3' end
Question 17
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Start codons in bacteria
Question 18
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eukaryotic cells always use AUG as a stop codon
Question 19
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fundamental unit of an ORF is a [blank_start]codon[blank_end]
Question 20
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What are the important functions of a start codon?
Answer
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specify first amino acid incorporation
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contains special interactions with tRNA for protein synthesis
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defines the reading frame for all subsequent codons
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allows for hydrogen bonding to other bases
Question 21
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Since the codons are a 3-nucleotide long, any stretch of mRNA could be translated in three different reading frames by overlapping.
Question 22
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Stop codons are UAG,UGA and UAA in both eukaryotes and prokaryotes
Question 23
Question
Eukaryotic mRNA recruit ribosomes by the shine-dalgarno sequence which is ribosome binding site(RBS) that recruit the translation machinery.
Question 24
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the ribosome binding site
Question 25
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limited complementarity and poor spacing promotes active translation
Question 26
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some prokaryotes lack a strong RBS but can still be actively translated by having a start and a stop codon right next to each other.
Question 27
Question
who uses their 5' and 3' modified ends to facilitate translation?
Answer
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bacteria
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prokaryotes
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eukaryotes
Question 28
Answer
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a purine, three bases upstream of the start codon and a guanine downstream
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extreme 5' end
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presence
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scanning
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interacts with initiator tRNA
Question 29
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5' cap allows the ribosome to be recruited in order to go through a process called scanning.
Question 30
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[blank_start]poly-A-tail[blank_end] at the end of mRNA enhances the level of translation of mRNA by promoting efficient recycling of [blank_start]ribosomes[blank_end].
Question 31
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[blank_start]tRNA[blank_end] molecules are 75 to 95 ribonucleotides in length which there are many types of.
Question 32
Question
The site at which amino acid is attached by the enzyme aminoacyl tRNA syntheses?
Answer
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D loop
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5'CCA3'
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anticodon loop
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TYC loop
Question 33
Question
Unusual bases found in tRNAs primary structure created by post-transcriptional modifications?
Answer
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pseudouridine
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dihydrouridine
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hypoxanthine
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uridine
Question 34
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principle features of the tRNA clover leaf are
Answer
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acceptor stem
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YU loop
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D loop
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anticodon loop
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constant loop
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variable loop
Question 35
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L-shape reveals the secondary structure of tRNA, which is stabilized by hydrogen bonds only.
Question 36
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charged tRNAs have an amino acid attached to them by amino alkyl linkage
Question 37
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acyl linkage is a high energy bond that is hydrolysis results in a large change in free energy, which helps drive the formation of peptide bonds
Question 38
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step one of aminoacyl-tRNA charging is [blank_start]adenylyation[blank_end] which amino acid reacts with ATP, amino acid is attached to adenylic acid via group transfer ester bond.
Question 39
Question
Whats the driving force that make adenylaltion energetically favorable reaction?
Question 40
Question
In step two of aminoacyl tRNA-charging- the adenylylated amino acid which is highly bound to the synthetase reacts with?
Answer
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tRNA
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PPI
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another amino acid
Question 41
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Class 2 tRNA syntheses enzyme attach the amino acid to the 2'OH of the tRNA and are generally monomeric.
Question 42
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each aminoacyl tRNA synthetase attaches a single amino acid to only one tRNA which is know as isoaccepting tRNAs.
Question 43
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most organism have 20 different tRNA synthetase
Question 44
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tRNA structure that determine recognition by specific aminacyl tRNA synthetases?
Question 45
Question
Why does aminoacyl-tRNA synthetase face a challenge in selecting the correct amino acid?
Answer
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small size
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side chains
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similarity
Question 46
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There is more proofreading after the aminoacyl-tRNA synthetase has used its editing pocket to charge tRNAs with low accuracy.
Question 47
Question
when cysteinyl-tRNA ^cys converted to alanine-tRNA^ cys ( by reduction) and added to a cell free protein synthesizing system, alanine-tRNA^cys introduces alanines at the codons that are suppose to be cysteine. why?
Answer
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ribosomes recognize tRNA not amino acid that its carrying
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wrong tRNA has been incorporated
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the tRNA is isoaccepting therefore can carry more than one amino acid
Question 48
Question
Eukaryotes can commence translation of the mRNA as it emerges from the RNA polymerase because the transcription machinery and the translation machinery are in the same compartment.
Question 49
Question
The ribosome is made up of large subunit which contains the [blank_start]peptidase transferase center[blank_end] and the small subunit that contains the [blank_start]decoding center[blank_end].
Question 50
Question 51
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When small and large subunits undergo of the ribosome associate with each other and the mRNA, translate the target mRNA, then dissociate after each round of sythesis.
Question 52
Question
translation occurs
Question 53
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substrate(s) for a round of amino acid addition are
Question 54
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The bond between the aminoacyl-tRNA and the amino acid is not broken during the formation of the next peptide bond.
Question 55
Question
What drives the peptide bond formation?
Question 56
Question
ribosomal RNAs are represent the main component of the ribosome because
Answer
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are located in the interior of the ribosome
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essential for the peptidyl transferase reaction and binding the anticodon loop of tRNAs
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are larger then proteins
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protein stable rRNA by shielding negative charges of their sugar phosphate backbones
Question 57
Question
what are the three binding sites for tRNA on a ribosome
Answer
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A site
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D site
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Enter site
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P site
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E site
Question 58
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peptidyl transferase center
Answer
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formed by 20 nucleotides of 23s RNA
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the 3'OH group of the tRNA in the P site is critical for activity and assist a concerted proton transfer
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orients tRNAs in optimal proximity for peptidyltransferase rxn to occur
Question 59
Question
what allows only unpaired RNA to pass through the small and large subunit of the ribosome?
Question 60
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[blank_start]Entry[blank_end] channel is through the small subunit which is only wide enough to let unpaired mRNA through and too narrow for a [blank_start]secondary[blank_end] structure. Ensures that codons in mRNA will be exposed and available for pairing with the anticodon loops of tRNA.
Question 61
Question
the kink in the mRNA between two codons are included after ribosome translocation to not allow any entry of the mRNA
Question 62
Question
[blank_start]Exit[blank_end] channel lets nascent polypeptide through. Some secondary structures can form inside but some can't. But [blank_start]tertiary[blank_end] and quaternary structure will not be formed until after its exit the ribosome.
Question 63
Question
Successful initiation in translation occurs when?
Answer
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ribosome is recruited to the mRNA
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ribosome placed over the start codon
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charged tRNA placed into P site
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tRNA goes through hydrolysis
Question 64
Question
translation initiation in prokaryotes is mostly done in the absence of the full ribosome
Question 65
Question
Specialized charged tRNA that binds directly to the P site and not the A site during initiation.
Answer
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met-tRNA
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initiator tRNA
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charged tRNA
Question 66
Question
One of the three initiation factors, that binds to the small subunit and block its from reassociating with the large subunit or from binding charged tRNAs.
Question 67
Question
purple-one of the three initiation factors in prokaryotes, it is a GTAPase which interacts with IF 1, charged initiator tRNA, and the small subunit.
yellow-prevents tRNAs from binding to the portion of the small subunit that will become part of the A site.
Question 68
Question
the last step in initiation is the 70s initiation complex, where fmet-tRNA, start codon, base pair which allows the small subunit to undergo a conformational change.
Question 69
Question
In eukaryotic initiation, the 43s pre-initiation complex
Answer
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1A attaches at the exit site
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Met-tRNA^met is bound to e1F3
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EIF1,3,5 are bound to the exit site
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the initiation factors attach to the 40s ribosome
Question 70
Question
recognition of eukaryotic mRNAs after 43S pre initiation complex,
Answer
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recognition of 5' cap mediated by 3 subunits
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recognition is mediated by a 3 subunit protein that specifically binds to RNA
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unstructured mRNA recruits the 43S pre initiation complex to mRNA by eIF4F and eIF5
Question 71
Question
once the complex is assembled at the 5' end of the mRNA, they move along the 5'-3' direction by a process that ATP-dependent
Question 72
Question
The reason why the initiator tRNA must bind to the small subunit before it binds to the mRNA is because it is used in scanning by recognizing the start codon through base pairing between anticodon of tRNA and start codon.
Question 73
Question
The binding of the large subunit to the small subunit in eukaryotes
Answer
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releases initiation factors by GTP hydrolysis
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FMet-tRNA is placed in the P site of the 80s initiation complex
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start codon and initiator tRNA in the P site is now ready to accept charged tRNAs
Question 74
Question
Poly-A-binding protein and eIF4G interact by the 5' and 3' end of the mRNA to
Answer
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make mRNA linear
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stabilize mRNA (exonucleases)
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decrease efficiency of translation
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helps recycling ribosomes
Question 75
Question
Exceptions to eukaryotic polypeptide being encoded by an open reading frame that starts with AUG?
Question 76
Question
eIF4G adaptor role when an mRNA is capped?
Answer
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eIF4G directly binds to IRES
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eIF4G binds to poly A tail
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eIF4G serves as an adaptor between the pre initiation complex and the EIF4E bound to it
Question 77
Question
Elongation is very different in prokaryotes and eukaryotes.
Question 78
Question
Whats this step in this mechanism?
Question 79
Question
When EF-Tu is bound to GDP and lacking any bound nucleotide it shows high affinity for aminoacyl-tRNAs.
Question 80
Question
What are one of the three mechanisms that contributes to the fidelity of codon recognition?
Question 81
Question
Third mechanism in correct codon-anticodon incorporation is [blank_start]accommodation[blank_end], which is rotation of tRNA into the peptidyl transferase center.
Answer
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accommodation
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GTP hydrolysis
Question 82
Question
Reason why ribosome is a ribozyme?
Answer
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23s RNA
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proteins
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aminoacyl-tRNA
Question 83
Question
23S rRNA catalyzes peptide bond formation by base pairing with the CCA variable loop of the tRNAs in the A and the P sites with help position alpha amino go of aminoacyl tRNA to attack carbonyl of growing peptide attached to peptidyl-tRNA.
Question 84
Question
[blank_start]EF-G[blank_end] is an elongation factor that completes translocation by binding to the ribosome's factor binding center with GTP.
Question 85
Question
[blank_start]molecular mimicry[blank_end] in which a protein takes on the appearance of a tRNA to facilitate association with the same binding site.
Answer
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molecular mimicry
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all elongation factor
Question 86
Question
Exchange of GDP for GTP for both EF-TU-GDP and EF-G-GDP are? ( in order)
Answer
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GDP release and binds to new GTP, exchanging GDP for GTP by complex
-
exchanging GDP for GTP by complex, GDP release and binds to new GTP,
Question 87
Question
Eukaryotic factors analogous to EF-Tu ([blank_start]eEF1[blank_end]) and EF-G([blank_start]eEF2[blank_end]) are name differently but have similar function.
Question 88
Question
how many molecules of ATP and GTP are used for peptide bond formation?
Answer
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2 ATP and 1 GTP
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2GTP and 1 ATP
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3 ATP and 0 GTP
Question 89
Question
Termination of translation is done by
Answer
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RF1: recognizes UGA
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release factors
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RF2: recognizes UGA
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eRF1
Question 90
Question
the name of the codon on the release factor the recognizes a stop codon?
Answer
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anticodon
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peptide anticodon
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GGQ
Question 91
Question
Class II release factor RF3,
Answer
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has higher affinity for GDP than GTP
-
conformational change in ribosome, the class 1 RF stimulates GDP to GTP exchange
-
No class 1 RF, RF-3-GDP has high affinity for ribosome
Question 92
Question 93
Question
Puromycin is an aminoglycoside antibiotic which binds to the 16rRNA causing misreading of the genetic code
Question 94
Question
tetracycline is a polyketide, which block the p site.
Question 95
Question 96
Answer
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in prokaryotes
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initiation factor
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tmRNA (tRNA/mRNA
Question 97
Question
What is this mechanism?
Question 98
Question
what machanism is this?
Question 99
Question
protein mediated regulation in bacteria
Question 100
Question
riboswitches are
Question 101
Question
regulation of translation by small RNA (sRNA) in bacteria
Question 102
Question
initiation in eukaryotic translation is globally regulated by
Answer
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rapamycin
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eIF4G
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elF4E-binding proteins
Question 103
Question
gene specific regulation of translation through cap sequestration in eukaryotes
Question 104
Question
Iron regulation is mediated by amino acids acting as sensor via steric hinderance
Question 105
Question
[blank_start]Translation[blank_end] of GCN4 is controlled by short upstream ORFs.