1. Which statement is TRUE regarding sigma factor proteins? a.they are found in
ID: 59710 • Letter: 1
Question
1. Which statement is TRUE regarding sigma factor proteins?
a.they are found in all three domains of life
b.they bind to RNA polymerase and to DNA at the promoter region
c.they bind to DNA at the operator and prevent RNA polymerase from binding there
d.they are required for transcription elongation and termination
e.they bind to the rho protein and facilitate transcription termination
2. The promoter for a gene is
a. where DNA polymerase binds to start gene expression
b. where the ribosome initiates translation of a gene
c. the first part of the gene that is transcribed
d. the site where RNA polymerase binds to start transcription of the gene
e. the location of the origin of gene replication
3. Bacterial sigma factors are important to
a. direct RNA polymerase to the promoter
b. assist in translation elongation
c. bind RNA polymerase to prevent it from binding the operator
d. initiate the transcription process by binding the initiation nucleotide
e. bind the operator and recruit RNA polymerase to the site
4. Which statement best describes translation initiation in Bacteria?
a. it starts immediately downstream of the promoter
b. the cap structure at the end of the mRNA tells the ribosome where to bind
c. the ribosome binding sites signals the appropriate location for translation initiation
d. the ribosom just uses the first ATG codon in the mRNA as the start codon
e. initiation occurs randomly, and incorrect proteins are just rapidly degraded and recycled
5. Codon bias is best explained by
a. the fact that some amino acids have more codons that specify them than others
b. the occurrence of one start codon but three stop codons
c. the observation that some organisms use different start and stop codons
d. the fact that different organisms use different abundance of tRNA molecules
e. the rule that some cell types will have more codons than some other cell types
6. Which molecule in the translation process contains both nucleotide and amino acid information?
a. the mRNA
b. the tRNA
c. the rRNA
d. the ribosomal proteins
e. the stop codon
7. True or False. During translation, the initiating tRNA contains fMet and binds to the P site in the ribosome.
8. During translation, the anticodon is found in ___________________, while the codon is found in ____________________.
9. The codon for a given amino acid is located in the ______________ and the anticodon is located in the _________________.
10. True or False. In the standard genetic code, there are often multiple codons for many of the common amino acids.
Explanation / Answer
1.
Sigma factor is a protein that initiates bacterial transcription. It binds to the DNA and enables the specific binding of RNA polymerase to the promoter site.
Hence, the correct option is b.
2.
Promoter is a region of DNA that initiates transcription of a particular gene. These are located on upstream of DNA and act as site for binding if RNA polymerase to initiate transcription of the gene.
Hence, the correct option is d.
3.
Sigma factor is a protein that initiates bacterial transcription. It binds to the DNA and enables the specific binding of RNA polymerase to the promoter site.
Hence, the correct option is a.
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