Chap 12.3 Notes: DNA to RNA - Transcription and Translation Notes
The nucleus and DNA
production of proteins:
DNA (gene)
controls cell activities by controlling the
RNA
Protein
Trait
* DNA is the “blueprint”
for a protein.
* RNA is a
copy of the “blueprint” that travels out
of the nucleus to the ribosome where, the protein is built.
* The protein then carries out its job and is expressed
as a trait.
Ex) eye color
The Genetic Code or “Blueprint”
 In DNA, the sequence of Nbases along one of the strands of
nucleotides is a “code” for protein production.
 The code is composed of sequences of three nitrogen bases called
Codon
that code for a specific amino acids.
 There are
64
different codons. See Codon Charts.
Transcription - Copying the “Blueprint” – Making RNA
 DNA
cannot
travel out of the nucleus to the ribosome.
Instead, another form of nucleic acid is required – RNA –
ribonucleic acid.
3 Parts of RNA Nucleotide
1) 5-C sugar – ribose
2) Phosphate
3) N – bases – Adenine, cytosine,
guanine, and a new one – URACIL.
There is no thymine in RNA.
A,C,G,
U
Phosphate
Ribose
Three Types of RNA
1) mRNA – messenger – copy of “blueprint” of how to build protein.
2) tRNA – transfer – carries amino acids to the ribosome - 20 different
types.
3) rRNA – ribosomal –
makes up the ribosome.
 To make RNA the cell carries out
transcription
Ex) DNA: ATT GAC CCT GAT GAC CAA
RNA: UAA CUG GGA CUA CUG GUU
.
 RNA is then sent to the ribosome and “translated” into a protein.
Translation – Making the Protein
Once the RNA has reached the ribosome , building
protein begins. This is called translation
.
of the
 First – the ribosome reads the mRNA one codon at a time.
 Second – the tRNA matches its
anticodon
to a
complimentary codon of mRNA.

The amino acid is
dropped off
bonds to build a protein.
and joined by peptide