33 1 .
During transcription , DNA is used as a template to guide the synthesis of RN
Transcription· Transcription -
process by which RNA is synthesized from a DNA template
similar to DNA
>
-
replication but synthesizes RNA molecule
Template strand unwound DNA strand used as model for Synthesis of RNA transcript
(noncoding antisense, minus
·
-
One ,
strand)
synthesized RNA complementary template (reverse complement)
>
-
is to
synthesized by RNA polymerase enzyme that adds nucleotides to 3 end of growing RNA aka growing transcript
· -
,
DNA strand not used as template for transcription =
nontemplate strand (coding , sense, plus strand)
·
Transcription =
3 stages :
① Initiation :
-RNA polymerase + proteins bind double-stranded DNA
-
DNA strands are separated
-
transcription of template begins
② Elongation :
RNA polymerase moves down template nucleotides added to 3' end of transcript
growing RNA
-
+ are
③ Termination :
RNA polymerase reaches in template strand that stops transcription releases
sequence transcript
-
+
Promoters's Transcription initiates + terminates at specific points along DNA molecule
Terminators
·
Promoters -
regions of a few hundred base pairs where RNA polymerase associated proteins bind
+ to DNA to initiate transcription
-
>
-
region in double-stranded DNA but only initiates -
on one strand
TATA box-sequence (5'-TATAAA-3') found in many promoters
·
-
·
Terminators -
sequence on DNA molecule that halts transcription
Different genes in same DNA molecule be transcribed from opposite strands
·
can
>
-
No one fixed template strand
depends of promoter
·
on orientation of promoter transcription
,
begins downstream
Transcription =
regulated process -
under certain conditions
ins
33 2 RNA .
polymerase adds successive nucleotides to the 3' end of the transcript a
RNA grows in 51-3' direction , moves along template in 31-5' direction
ribonucleotide only accepted pairs properly match
>
-
if base
phosphates released
>
-
uses one phosphate group to provide energy ,
other two
group of growing strand attacks innermost phosphate of
>
-
OH
incoming nucleotide drive rx is released
energy to
-
,
very efficient
o
RNA does not proofreading function error rate is much
>
-
polymerase have higher
·
During transcription , DNA is used as a template to guide the synthesis of RN
Transcription· Transcription -
process by which RNA is synthesized from a DNA template
similar to DNA
>
-
replication but synthesizes RNA molecule
Template strand unwound DNA strand used as model for Synthesis of RNA transcript
(noncoding antisense, minus
·
-
One ,
strand)
synthesized RNA complementary template (reverse complement)
>
-
is to
synthesized by RNA polymerase enzyme that adds nucleotides to 3 end of growing RNA aka growing transcript
· -
,
DNA strand not used as template for transcription =
nontemplate strand (coding , sense, plus strand)
·
Transcription =
3 stages :
① Initiation :
-RNA polymerase + proteins bind double-stranded DNA
-
DNA strands are separated
-
transcription of template begins
② Elongation :
RNA polymerase moves down template nucleotides added to 3' end of transcript
growing RNA
-
+ are
③ Termination :
RNA polymerase reaches in template strand that stops transcription releases
sequence transcript
-
+
Promoters's Transcription initiates + terminates at specific points along DNA molecule
Terminators
·
Promoters -
regions of a few hundred base pairs where RNA polymerase associated proteins bind
+ to DNA to initiate transcription
-
>
-
region in double-stranded DNA but only initiates -
on one strand
TATA box-sequence (5'-TATAAA-3') found in many promoters
·
-
·
Terminators -
sequence on DNA molecule that halts transcription
Different genes in same DNA molecule be transcribed from opposite strands
·
can
>
-
No one fixed template strand
depends of promoter
·
on orientation of promoter transcription
,
begins downstream
Transcription =
regulated process -
under certain conditions
ins
33 2 RNA .
polymerase adds successive nucleotides to the 3' end of the transcript a
RNA grows in 51-3' direction , moves along template in 31-5' direction
ribonucleotide only accepted pairs properly match
>
-
if base
phosphates released
>
-
uses one phosphate group to provide energy ,
other two
group of growing strand attacks innermost phosphate of
>
-
OH
incoming nucleotide drive rx is released
energy to
-
,
very efficient
o
RNA does not proofreading function error rate is much
>
-
polymerase have higher
·
