What property of different sigma factors allows them to bind to different promoters?
different amino acid sequences resulting in different spatial arrangements of chemical groups
A promoter is _____.
a sequence in DNA that binds RNA polymerase near the site for transcription
What is the function of the -10 box and -35 box of the promoter?
they bind the sigma subunit that is associated with RNA polymerase.
Put the following events of transcription in chronological order.
1. Sigma binds to the promoter region.
2. The double helix of DNA is unwound, breaking hydrogen bonds between complementary strands.
3. Sigma binds to RNA polymerase.
4. Sigma is released.
5. Transcription begins.
3, 1, 2, 5, 4
How are RNA hairpin turns related to termination?
The turns are formed from complementary base pairing and cause separation of the RNA transcript and RNA polymerase
Which molecule or reaction supplies the energy for polymerization of nucleotides in the process of transcription?
the phosphate bonds in the nucleotide triphosphates that serve as substrates
Eukaryotes have three nuclear RNA polymerases. The primary function of RNA polymerase II is _____.
transcription of protein-coding genes (mRNA)
Which of the following initially determines which DNA strand is the template strand, and therefore in which direction RNA polymerase II moves along the DNA?
the specific sequence of bases along the DNA strands
During RNA processing a(n) _____ is added to the 5' end of the RNA.
modified guanine nucleotide
During RNA processing a(n) _____ is added to the 3' end of the RNA.
a long string of adenine nucleotides
Spliceosomes are composed of _____.
snRNPs and other proteins
Translation occurs in the _____.
In eukaryotes, when mRNA is hybridized to complementary DNA, _____.
introns loop out as single-stranded regions of DNA
What molecule in the spliceosome lowers the activation energy so intron removal reactions can occur?
One function of polyribosomes is to _____.
increase the rate of polypeptide synthesis from a single mRNA
Ribosomes can attach to prokaryotic messenger RNA ___.
before transcription is complete
What is recognized by an aminoacyl tRNA synthetase?
one amino acid and the set of tRNAs that is coupled to that amino acid
What molecule/feature ensures that the correct amino acid is added with reading of a specific codon during translation?
the anticodon of a properly formed aminoacyl tRNA
Where does translation take place?
Which nucleic acid is translated to make a protein?
Which of the following steps occurs last in the initiation phase of translation?
The large ribosomal subunit joins the complex.
What is meant by translocation?
The ribosome slides one codon down the mRNA.
How does the bacterial ribosome recognize where to start translation?
The small ribosomal subunit binds to a sequence in the mRNA just upstream of the start codon
Put the following events of elongation in prokaryotic translation in chronological order.
1. Binding of mRNA with small ribosomal subunit
2. Recognition of initiation codon
3. Complementary base pairing between initiator codon and anticodon of initiator tRNA
4. Base pairing of the mRNA codon following the initiator codon with its complementary tRNA
5. Attachment of the large subunit
The ribosome-binding site of prokaryotes is also known as _____.
the Shine-Dalgarno sequence
Which answer most accurately summarizes the role of aminoacyl tRNA synthetases in gene expression?
enzymes that attach amino acids to tRNAs