15.2 Prokaryotic Transcription

Question 1

plasmids

Answer 1

shorter, circular DNA molecules that may only contain one or
a few genes.

Question 2

transcription bubble

Answer 2

region of locally unwound DNA that
allows for transcription of mRNA

Question 3

template strand

Answer 3

strand of DNA that specifies the
complementary mRNA molecule

Question 4

initiation site

Answer 4

the +1 site, nucleotide from which mRNA synthesis
proceeds in the 5’ to 3’ direction; denoted with a “+1

Question 5

core enzyme

Answer 5

the polymerase is composed of five
polypeptide subunits, two of which are identical. Four of these subunits, denoted α, α, β, and β’

Question 6

holoenzyme

Answer 6

The polymerase comprised of all five subunits

Question 7

promoter

Answer 7

DNA sequence onto which the transcription machinery, including RNA polymerase, binds and initiates transcription

Question 8

Rho-dependent termination

Answer 8

in prokaryotes, termination of
transcription by an interaction between RNA polymerase
and the rho protein at a run of G nucleotides on the DNA
template

Question 9

rho-independent

Answer 9

termination sequence-dependent
termination of prokaryotic mRNA synthesis; caused by
hairpin formation in the mRNA that stalls the polymerase

Question 10

stable hairpin

Answer 10

causes the polymerase to stall as soon as it
begins to transcribe a region rich in A–T nucleotides