Protein Synthesis Notes
UNLIKE DNA, RNA…
Contains the sugar
ribose instead of
deoxyribose.
2. Single-stranded
instead of double
stranded.
3. Contains uracil in
place of thymine.
1.
Three Main Types of RNA
Messenger RNA (mRNA) - Carries copies of
instructions for the assembly of amino acids
into proteins from DNA to the rest of the cell
(serve as “messenger”)
2. Ribosomal RNA (rRNA) – Makes up the major
part of ribosomes, which is where proteins are
made.
3. Transfer RNA (tRNA) - Transfers amino acids
to ribosomes during protein synthesis
1.
Remember Proteins?
 They are BIOMOLECULES!
 Proteins are made up of a chain of amino acid
monomers and they are formed at the ribosomes!
 Proteins can be enzymes, which catalyze and
regulate chemical reactions. Proteins also make up
our structure!
2 Steps to Make a Protein:
1. Transcription

DNA → RNA
2. Translation

RNA → Protein
(Chain of amino
acids)
TRANSCRIPTION
NUCLEUS
First part of protein synthesis:
Transcription
 Transcription = DNA  RNA
 Takes place in the nucleus.
 Two enzymes help:
1. Helicase - separates DNA helix
2. RNA polymerase – brings RNA
nucleotides over to be
synthesized into mRNA
 Template strand: the side of
DNA that will be used to create
an mRNA strand
Transcribing the Genetic Code:
 The genetic code is read three letters at a
time, called “codons” on the mRNA strand
 The genetic code (language) from DNA is
transcribed into mRNA during transcription.
Each codon will have
a special amino acid
that matches it!
Transcription: (DRAW THIS)
Transcription Animations
 http://www.ncc.gmu.edu/dna/mRNAanim.htm
 http://www.johnkyrk.com/DNAtranscription.html
 http://www-
class.unl.edu/biochem/gp2/m_biology/animation/
gene/gene_a2.html
 http://207.207.4.198/pub/flash/26/transmenu_s.s
wf (very good but need to skip some parts)
IN YOUR OWN WORDS…
 In your notebook, below the drawing-
Describe the purpose and process of
transcription.
Use these stems!
The purpose of transcription is….
The process of transcription is …
After Transcription…
 The mRNA leaves
the nucleus and
travels to the
ribosomes in the
cytoplasm.
 The ribosomes
are the only place
to BUILD proteins.
TRANSLATION
RIBOSOMES IN THE
CYTOPLASM
Second part of protein synthesis:
Translation
 Translation = mRNA  protein
 Takes place at the ribosomes
 mRNA that was transcribed leaves the nucleus and attaches
to the ribosome.
 One codon at a time is matched to a tRNA “anticodon”.
 When tRNA sits down at it’s matching codon,
the amino acid it carries is dropped off and
bonded to the protein chain
by peptide bonds.
NOW YOU HAVE A PROTEIN!
Translation (DRAW THIS)
ANTICODON
CODON
EXAMPLE:
The tRNA molecule for methionine (an amino acid) has the
“anticodon” UAC which matches to the “codon” AUG.
An amino acid chart is used to find out which
amino acid joins the protein chain next!
ALWAYS read the mRNA codon!
Translation Animations
 http://207.207.4.198/pub/flash/26/transmenu_
s.swf (very good animation!)
IN YOUR OWN WORDS…
 In your notebook, below the drawing-
Describe the purpose and process of
translation.
Use these stems!
The purpose of translation is….
The process of translation is …
Illustrations…
First part of protein synthesis:
_______________________________
 ________________ = ____________  ______________
 Takes place in the _____________.
 Two enzymes help:
1. __________ - separates DNA helix
2. __________________– brings RNA nucleotides over to be
synthesized into mRNA
 _________________: the side of DNA that will be used to
create an mRNA strand
 The genetic code is read _________________________
called ___________on the mRNA strand
 The genetic code (language) from DNA is transcribed into
mRNA during ______________________.
Second part of protein synthesis:
________________________
 __________________ = ______________  ____________
 Takes place at the _____________________.
 mRNA that was transcribed ___________________________
and attaches to a ____________________.
 One codon at a time is matched to a ___________________.
 When tRNA sits down at it’s matching codon, the
____________________it carries is ___________________
and bonded to the protein chain by _________________.
NOW YOU HAVE A _________________________!