1. Chapter 13.2 (Pgs. 366-371): Ribosomes and Protein Synthesis

2. The Genetic Code
A gene is a section of DNA that codes for a trait, usually a protein
This code specifies the order of amino acids in a protein
This code is made of 3-letter “words” called codons
Codons in mRNA have 3 RNA nucleotides (A, C, G or U)
Each codon stands for an amino acid

4. Protein Synthesis Is also called translation Occurs in the cytoplasm
Is the process of assembling a protein using the sequence of codons in mRNA
Also requires ribosomes and tRNA
Ribosomes help bond amino acids together
tRNA has anticodons that are complementary to mRNA codons

6. Steps in Translation
A ribosome attaches to mRNA molecule, and begins reading the mRNA at the “start” codon
tRNA brings in an amino acid that matches the mRNA codon
The ribosome helps amino acids bond to each other, and moves the growing polypeptide over to make room for the next amino acid
When the ribosome reaches a “stop” codon, it releases the mRNA and the protein

8. The Central Dogma of Molecular Biology
Information is transferred from DNA to RNA to protein
DNA -> RNA -> Protein
Proteins create traits
This is called gene expression
This process is found in all organisms

11. Differences in Transcription and Translation
Occurs in the nucleus
Makes RNA
Uses DNA as a template
Uses RNA polymerase
Uses RNA nucleotides as the building blocks
Occurs in the cytoplasm
Makes a protein
Uses mRNA as a template
Uses ribosomes and tRNA
Uses amino acids as the building blocks