1. Protein Synthesis Translation
Chapter 12, Section 3

2. I. Protein Structure, Composition and Translation of Proteins
A. Proteins a sequence of amino acids linked together by peptide bonds, that form a polypeptide chain.
There are 20 different amino acids, subunit and polymers of proteins that make up all the proteins in our body. Nucleotides are the monomers.

3. II. The Genetic Code
A. A sequence of nucleotides in an mRNA transcript, translated into a sequence of amino acids.
B. The genetic code is a triplet of nucleotides in mRNA, called a codon, this determines the sequence of amino acids in a protein.

5. III. Genetic Code
2. 64 codons make 20 amino acids, 3 of those 64 code for stop codons, which are NOT amino acids. (61 codons, coding for an amino acid)
3. Special codons starts and stops the translation
a. Start codon: AUG, also codes for methionine.
b. Stop codon: UAA, UAG, and UGA, these are not counted as amino acids, but are counted as a codon.

6. IV. Translation
A. Translation is the process of assembling amino acids from mRNA single chain, forming polypeptides, proteins.
1. Steps in Translation
1. mRNA leaves the nucleus, with the copied single strand of DNA, and migrates to a ribosome in the cytoplasm.

7. 2. tRNA picks up Amino acids floating freely in the cytoplasm, and begins traveling to the ribosomes.
a.tRNA regions - two main regions; one region binds to an amino acid, and one region binds to the mRNA at the anticodon site.

8. Anticodon
A. A group of 3 bases on tRNA molecule that are complementary to an mRNA codons.
B. This complementary pairing insures that the correct amino acids is linked to form the specific protein.

9. VI. Base-Pairing Rules in RNA
DNA is AGCTCGGAT, RNA is UCGAGCCUA.

10. VII. Ribosomes
A. Ribosomes are the site of protein synthesis

11. VIII. Protein Assembly
3: mRNA reaches the ribosome and attaches the start codon to it.
4: tRNA reaches the ribosome with methionine on one region and anticodon on the other and attaches.

12. 5: Ribosome moves over one to the right, leaving an open spot
6: tRNA brings a new amino acid to the chain.

13. 7. Ribosome continues moving down the mRNA strand until a stop codon is
reached.

14. 8. Amino acid chain is released
and mRNA is recycled.