1. The Central Theme of Molecular Biology is Protein Synthesis Step I: Going from DNA to RNA called Transcription Step II: Going from RNA to Protein called Translation Step IStep II

2. The 3 types of RNA involved in Protein Synthesis mRNA = Messenger RNA –Carries information from nucleus to cytoplasm rRNA = Ribosomal RNA –Make ribosomes which are where amino acids are assembled into proteins tRNA = Transfer RNA –Carries amino acids to the ribosome to be assembled into proteins

3. Step 1 in Protein Synthesis is Transcription Transcription is the process of making mRNA from DNA and then moving the mRNA from the nucleus to the cytoplasm where protein synthesis takes place.

4. First: Enzymes (RNA polymerase) unzip the molecule of DNA at the gene being transcribed

5. 2 nd : –A complementary mRNA strand is assembled using a template DNA strand

6. Third: –The new mRNA strand leaves the nucleus and enters the cytoplasm where it goes to the ribosome.

7. Summary of Transcription 1.It is the first stage of protein synthesis. 2.mRNA copy is made from a DNA template 3.mRNA copy travels from the nucleus to the cytoplasm

8. Step 2 in Protein Synthesis is Translation Process of converting the mRNA strand information into amino acids using codons. Takes place at ribosomes located in the cytoplasm Amino Acids

9. Why is it called translation? RNA is written in the language of nucleotides –A U G C U A Proteins are written in the language of amino acids –There are 20 amino acids that are the building blocks of proteins –Examples are arginine, histidine, glycine, etc…… This means that the RNA message must be translated into amino acids during translation and we use CODONS to do this!

10. mRNA Codons A codon (triplet) is a group of three nucleotides on mRNA that codes for a specific amino acid Each amino acid has it’s own codon and sometimes more than one codon! Codon examples: UCG = serine CAU = histadine UUU = phenylalanine

11. A CODON CHART

12. Codons continued Codons are the code that tells ribosomes 1.Which amino acid to attach next 2. Where to start translation 3. Where to stop translation

13. Practice Time! Okay practice time is now over!

14. tRNAs: Transfer RNA Consists of 80 RNA nucleotides Has an Anticodon which is made to pairs up with an mRNA codon tRNAs carry the amino acids to the ribosome Anticodon

15. Steps of Translation 1. mRNA attaches to ribosome at the start codon 2. A tRNA carrying an amino acid approaches 3. The Anticodon on the tRNA pairs with codon 4. The tRNA drops off it’s amino acid 5. An enzyme forms a peptide bond between amino acids 6. This process continues to form a protein until a STOP codon is reached and then the new protein is released.