Bio1151
Chapter 17
From Gene to Protein
A major function of DNA is to direct the synthesis of
in two
steps
:
and
; this flow of information is known as the central
.
In
prokaryotes
, transcription and translation take place
.
In eukaryotes, an intermediate
step
of RNA
is needed due to the presence of the
.
Transcription
has three stages:
,
, and
.
Transcription review and exercise:
In eukaryotes, the transcript is a
and needs to be
processed
to form the mature
that will used in translation.
RNA Processing review:
The genetic information on mRNA is encoded as a sequence of RNA
triplets
, or
.
The
possible codons constitute the genetic
code
.
The mature mRNA exits the nucleus, and translation takes
place
on
, together with
RNA (tRNA).
The
on the transfer RNA (
tRNA
) binds with the mRNA
to add a specific amino acid to the polypeptide chain.
Translation
also has three stages:
,
, and
.
Translation review:
Central dogma
summary
.
are changes in the DNA of a cell which may lead to an abnormal
.
mutations
are changes in one pair of nucleotides.
A base-pair
substitution
mutation may result in a
,
, or
mutation.
Insertions and
of nucleotide pairs may produce
mutations
.