Transcript RNA Polymerase

The big picture………
http://www.biologie.uni-hamburg.de/b-online/library/bio201/trinity.gif
Overview of Transcription
Transcription

Helicase-Unzips a gene in
DNA
 RNA Polymerase- Matches
up bases to one side of gene
 A-U and C-G
 RNA splicing
– introns are removed (stay
“in”nucleus)
– exons are joined together as
mRNA (“exit the nucleus)


mRNA detaches from the DNA
mRNA moves out of the
nucleus into the cytoplasm.
mRNA is made from 1 gene in DNA.
 The type of RNA made is called mRNA
(messenger RNA) because it sends a
message from DNA to the cytoplasm.
 tRNA (Transfer RNA) & rRNA
(Ribosomal RNA) are also made during
transcription to use in translation.

How does mRNA tell the cell what
to do?





mRNA is a message that codes for a protein
Proteins are made in the cytoplasm and then
work to keep the cell alive
Translation (protein synthesis): Process of
making a protein
Proteins are made up of amino acids (small
building blocks)
There are 20 different types of amino acids
Transcription & Translation
http://learn.genetics.utah.edu/units/basics/transcribe/
Transcription & Translation
http://learn.genetics.utah.edu/units/basics/transcribe/
DNA Translation (Changing RNA to Proteins)
There are 4 steps to summarize translation:
1.
The mRNA attaches to the ribosome
2.
On a ribosome (in the cytoplasm) the tRNA (Transfer
RNA) carries an amino acid that matches the codon on
the mRNA strand.
a.
So if the mRNA strand has the codon UUA
then you would look on the Amino Acid Chart
& you will find that UUA codes for the amino
acid Leucine
3.
The different amino acids from the multiple tRNAs start
to bond together to make a protein
4.
The ribosome continues to translate the mRNA
message until a STOP codon is reached.
a.
The protein then detaches from the ribosome
& is in the cell to use.
http://learn.genetics.utah.edu/units/basics/transcribe/
DNA
Translation
http://www.biologie.uni-hamburg.de/b-online/library/bio201/trinity.gif
DNA
Translation
http://www.biologie.uni-hamburg.de/b-online/library/bio201/trinity.gif
DNA Translation
http://www.biologie.uni-hamburg.de/b-online/library/bio201/trinity.gif
DNA Translation
http://www.biologie.uni-hamburg.de/b-online/library/bio201/trinity.gif