1. DNA &
Translation

2. DNA and Translation
Gene: section of DNA that creates a specific protein
Approx 25,000 human genes
Proteins are used to build cells and tissue
Protein synthesis involves two processes:
1) Transcription
2) Translation

3. Transcription Review Transcription takes place in the nucleus
1) DNA double helix is broken apart
2) mRNA nucleotides match up
3) Finished mRNA detaches, and moves to a ribosome

4. The Genetic Code Codon: Combination of 3 mRNA nucleotides
Each mRNA codon matches with 1 of 20 amino acids
Ribosome reads codons 1 at a time
Codon AUG = Methionine (Start)
Codon GUU = Valine
Codons UAA or UAG or UGA = Stop

5. Translation Overview Defined: Process of making proteins
Step 1: mRNA enters ribosome
Step 2: Ribosome reads one mRNA codon at a time
Step 3: tRNA delivers amino acids until a protein is created

6. Translation Details
Translation begins when the mRNA codon “AUG” is read by the ribosome
Each mRNA codon matches with a specific amino acid
AUG = methionine
GCU = alanine
tRNA carries over the proper amino acid
tRNA anticodon matches with the mRNA codon
Ensures proper match
One by one, amino acids are linked together
Translation ends when a “stop” codon is read by the ribosome
End result: Protein

7. GAU AUG CCG AGU CCA GGA UCU UGA
Methionine
Proline
Serine
Proline
Glycine
Serine
Ribosome
tRNA
UAC
tRNA
GGC
tRNA
UCA
tRNA
GGU
tRNA
CCU
tRNA
AGA
GAU AUG CCG AGU CCA GGA UCU UGA

8. Because the codon and anticodon don’t match, this amino acid is not released from the tRNA. It will simply float away and the process will continue. This prevents errors.

9. Threonine T G A A C U U G A DNA mRNA codon tRNA anticodon Amino Acid
Practice Problem
Always use mRNA to find the amino acid
DNA
mRNA codon
tRNA anticodon
Amino Acid
Threonine
T G A
A C U
U G A

10. Lysine T T C A A G U U C DNA mRNA codon tRNA anticodon Amino Acid
Practice Problem
Always use mRNA to find the amino acid
DNA
mRNA codon
tRNA anticodon
Amino Acid
Lysine
T T C
A A G
U U C

11. C A G U C A glycine DNA mRNA codon tRNA anticodon Amino Acid
Practice Problem
Always use mRNA to find the amino acid
DNA
mRNA codon
tRNA anticodon
Amino Acid C A G U C A
glycine

12. Kobe Kuiz Define transcription? Translation?
What are genes and how are they different from chromosomes?
How many nucleotides make a codon?
The anticodon can be found on which object?
The anticodon must match the ______.
Place the following steps in order from start to finish:
Proteins are assembled
Ribosome reads a codon one at a time
mRNA arrives at the ribosome
tRNA delivers amino acids to the ribosome
7) Be able to solve practice problems similar to the three examples on slides #9-11.