1. How does the body use DNA to create proteins? CENTRAL DOGMA
Protein Synthesis
How does the body use DNA to create proteins?
CENTRAL DOGMA

2. Review
DNA contains the ‘instructions for the cell’ or instructions for making proteins
Proteins are long chains of amino acids bound together (also called polypeptides)

3. Protein synthesis Has 2 different steps = making proteins
Transcription
Translation

4. Step 1 = Transcription Where does transcription start and end?
Overview: section of DNA is copied into a piece of mRNA
RNA polymerase separates one section (a specific gene) of DNA in the nucleus and uses one strand as a template to make the mRNA strand
 Where does transcription start and end?
Specific nucleotides tell the process when to start and stop
The start sequence is called a promoter
Initiates transcription by allowing RNA polymerase to bind to one side of the DNA
The stop sequence is called the terminator
Signals end of gene and stops the process

5. What does the transcribed DNA tell us?
Just like DNA, mRNA nucleotides are ‘read’ 3 at a time
Called a codon
Each codon specifies for a particular amino acid
The order of mRNA codons determines the order of amino acids that will be linked together during our next step
Practice
Original strand
TAC GGA TTC CGT TTT AAG ACT
mRNA complementary strand

6. Step 2 = Translation
Overview = mRNA is read at the ribosome by tRNA which brings amino acids to build our polypeptide chains (proteins)
tRNA
Amino Acids themselves cannot recognize codons on the mRNA, so the tRNA helps them ‘translate’
Each tRNA carries only one type of amino acid
The three nitrogen bases on the tRNA are called anticodon
Complementary to the mRNA codon
Original strand
AUG UUU GUG CCU GGU UGA
tRNA complementary strand