1. Chapter 10: DNA, RNA and Protein Synthesis
Translation
Chapter 10: DNA, RNA and Protein Synthesis

2. The Genetic Code
The Genetic Code is the term for the rules that relate how a sequence of nitrogenous bases in nucleotides corresponds to a particular amino acid.
In the Genetic Code, three adjacent nucleotides (“letters”) in mRNA specify an amino acid (“word”) in a polypeptide.

3. Codon
A sequence of three nucleotides that encode for an amino acid or signifies a start or stop signal.
Examples:
UUU = phenylalanine
AUG = start

4. The Genetic Code

5. Examine the sequence of three bases: UAC

6. Codons There are 64 possible codons corresponding to 20 amino acids
Each amino acid has more than one possible codon.
There are Start and Stop signals built into the code.
The Start codon corresponds to the amino acid methionine.

7. Flow of Information
The sequence of nitrogenous bases in DNA becomes complementary to the sequence of bases in the mRNA molecule during TRANSCRIPTION.
tRNA molecules bring amino acids to the ribosome and match up their complementary bases to the mRNA molecule during TRANSLATION.

8. Translation
The making of a protein by stringing together amino acids to make a polypeptide chain.
Information flows from DNA to mRNA and then tRNA brings the corresponding amino acid.
Peptide bonds are formed between adjacent amino acids and a polypeptide chain is formed.

9. Translation - What is it? The making of a protein
Where does it take place?
Prokaryotes = cytoplasm
Eukaryotes = cytoplasm
What is needed?
mRNA, 2 ribosomal subunits, tRNA and
amino acids

10. Initiation: Steps of Translation
The ribosomal subunits, the mRNA, and the tRNA carrying methionine bind together.

11. Initiation

12. Elongation
The tRNA carrying the amino acid sequence specified by the next codon binds to the codon.
A peptide bond forms between adjacent amino acids
The ribosome moves the tRNA and mRNA.

13. Elongation

14. (Continued Elongation)
The first tRNA detaches and leaves its amino acid behind.
Elongation continues.
The polypeptide chain continues to grow.

15. Elongation (continued)

16. Termination The process ends when a stop codon is reached.
A stop codon is one for which there is no tRNA molecule that has a complementary anticodon.

17. Disassembly
The ribosome complex falls apart. The newly made polypeptide is released.

18. Summary Information flows from DNARNAProteins
RNA serves as the intermediary between DNA and proteins.
There are three types of RNA. mRNA, rRNA and tRNA.
The Genetic Code represents 64 possible codons corresponding to 20 different amino acids, start signal and stop signals.
The process of TRANSLATION takes place within the cytoplasm on a ribosome.
The process of TRANSLATION involves: initiation, elongation and termination.