1. Protein Synthesis Honors Biology Mrs. Speirs
Awesome Animation of the Protein Synthesis Process

2. Protein Synthesis
…to make proteins

3. Transcription = DNA serves as the template for the synthesis of mRNA
= DNA → RNA (nucleus)
= DNA serves as the template for the
synthesis of mRNA
= RNA polymerase travels along the DNA strand
= base pairing rule C…G and A..U
= Synthesis of the RNA proceeds in the
5′ → 3′ direction
= undergo processing steps in the nucleus
to produce functional mRNA molecules that will
diffuse into the cytoplasm for translation

4. Transcription The gene of interest (template strand of DNA) is copied.
DNA (gene of interest)
5’ ATGGCCTGGACTTCA 3’
3’ TACCGGACCTGAAGT 5’ (TEMPLATE STRAND) Transcribed mRNA
5’ AUGGCCUGGACUUCA 3’ mRNA

5. The genetic code consists of 64 triplets of nucleotides.
There are three nucleotides (triplet)
code for one amino acid.
These triplets are called codons.
The genetic code can be expressed as
either RNA codons or DNA codons.
mRNA codons are actually "read" during
the synthesis of proteins...translation.

6. Remember Transcription occurs in the nucleus…
DNA
5’ ATGGCCTGGACTTCA 3’
3’ TACCGGACCTGAAGT 5’ (TEMPLATE STRAND) 5’ AUGGCCUGGACUUCA 3’ mRNA
mRNA diffuses into the cytoplasm to begin
the process of Translation…
5’ AUGGCCUGGACUUCA 3’ mRNA
Amino Acids
Assemble
Met
Ala
Trp
Thr
Ser

7. In a gene, the specific sequence
of the nucleotides specifies for a
specific sequence of amino acids.
In the cytoplasm, rRNA reads the
mRNA codons.
Transfer RNA molecules are specific
for one amino acid and for a particular
triplet of nucleotides in the mRNA codon.
The family of tRNA molecules enables the
codons in a mRNA molecule to be
translated into the sequence of amino acids
in the protein.

8. Analogy Analogy: Forming three lettered word sentences
Triplet Codons of DNA = three lettered words
Triplet Codons of mRNA = three lettered words
Triplet anti-codon for tRNA = three lettered words
Amino acids brought by tRNA = three lettered words
Sequence of amino acids that form the protein =
The sentence formed by the three lettered words.

9. THEeioDtOGufcSAT THE D OG SAT mRNA Processing Steps Pre Cursor mRNA
Introns = nitrogen bases that do not code for
Amino acids.
Removed by restriction enzymes.
THE D OG SAT
Exons = nitrogen bases that do code for
Amino acids
Joined by ligase enzymes Add a Guanine cap and poly-Adenine tail

10. Translation mRNA codes  Protein Three Lettered Words  Sentence
G-cap…THE DOG SAT…poly-A tail
Mature mRNA = ready to diffuse into the cytoplasm
for the second part of protein synthesis.
Translation
mRNA codes  Protein
Three Lettered Words  Sentence

11. Translation This mature mRNA diffuses into the cytoplasm.
G-cap…THE DOG SAT…poly-A tail
This mature mRNA diffuses into the cytoplasm.

12. A ribosome (rRNA) attaches—reading the
DOG
SAT
SAT
THE
THE
nucleus
cytoplasm
G-cap…THE DOG SAT…poly-A tail
rRNA
THE
DOG
THE
DOG
rRNA
SAT
DOG
SAT
A ribosome (rRNA) attaches—reading the
mRNA codons (the triplet nucleotide sequence).

13. tRNA
DOG
SAT
SAT
THE
THE
nucleus
cytoplasm
G-cap…THE DOG SAT…poly-A tail
rRNA
THE
DOG
THE
DOG
rRNA
SAT
DOG
SAT
Specific tRNAs grab the specific amino acid needed by the rRNA the molecule that reads the
mRNA codons.

14. DOG
SAT
SAT
cytoplasm
THE
nucleus
THE
G-cap…THE DOG SAT…poly-A tail
tRNA
THE
DOG
THE
DOG
rRNA
SAT
DOG
SAT
Specific tRNAs grab the specific amino acid to match the specific codon in the mRNA.

15. DOG
SAT
SAT
cytoplasm
THE
nucleus
DOG
tRNA
THE
G-cap…THE DOG SAT…poly-A tail
tRNA
THE
rRNA
DOG
THE
DOG
SAT
DOG
SAT
Peptide (covalent) bonds are formed between the amino acids (words in the sentence).

16. DOG
SAT
SAT
cytoplasm
THE
nucleus
SAT
tRNA
DOG
tRNA
THE
G-cap…THE DOG SAT…poly-A tail
rRNA
THE
DOG
THE
DOG
SAT
DOG
SAT
Once the ribosome reaches the end of the mRNA it will read the stop codon (the period at the end of the sentence) and then, it will release the protein into the cytoplasm.

17. SAT DOG THE The newly assembled “protein”…
cytoplasm
THE
nucleus
SAT
DOG
THE
G-cap…THE DOG SAT…poly-A tail
THE
rRNA
DOG
THE
DOG
rRNA
SAT
DOG
SAT
The newly assembled “protein”…
“THE—DOG—SAT”…is released into the cytoplasm.

18. Source Sites