1 Protein Synthesis Transcription and Translation DNA’s destiny! rlifeandgenetics/dna/ rlifeandgenetics/dna/

2 What does DNA really do? A. The DNA code must code for something right??? So what IS IT???? B. The DNA alphabet essentially codes for amino acids C. Which are the building blocks for……. 1. PROTEINS!!!!!!!!!!

3 What is RNA?

4 Where is RNA Found? __________________________________ RNA Type Found Function Messenger (mRNA)Nucleus/Cytoplasm Decodes DNA Transfer (tRNA) At the ribosome Decodes mRNA into amino acid codes Ribosome (rRNA) ribosome Helps connect amino acids to make protein

5 From DNA to Protein: D. This occurs in several organized steps in 2 phases 1. PHASE 1: a. Transcription 1) DNA IS TRANSCRIBED INTO READABLE FORM (mRNA) 2.PHASE 2: a. Translation 1) mRNA IS TRANSLATED TO CODE FOR AMINO ACIDS

6 Transcription: The Video Clip

7 Phase 1: Transcription A. Occurs INSIDE THE NUCLEUS B. DNA strands separate C. Complimentary RNA bases take their places along DNA with the help of enzymes 1. RNA bases are A, C, G, and U (uracil) 2. U instead of T! D. This creates an mRNA strand Let’s see this in action! Let’s see this in action!

8 Let’s practice making a complimentary mRNA from a DNA strand! Remember: C-G and A-U DNA mRNA C G A T T A G A T G C U A A U C U A

9 Protein Synthesis: The Video Clip

10 Let’s talk about Proteins…the ultimate result A. Long chains formed by 20 different amino acids B. Protein shape is determined by DNA sequence! C. DNA transcribed to mRNA D. mRNA now codes for amino acids! HOW YOU THINK??

11 RNA Review owthanddevelopment/rna/preview.weml owthanddevelopment/rna/preview.weml

12 Proteins…the ultimate result cont.: So glad you asked!!! E. 3 mRNA bases code for an amino acid! 1. Ex. GCU codes for Alanine 2. This is called a CODON F. Each amino acid has more than one codon! G. G. Polypeptide: 1. String of amino acids

13 1. The strand we made earlier is: G C U | A A U | C U A 2. If 3 bases code for an amino acid, how many amino acids are coded in our strand? 3 of course! G C U | A A U | C U A Alanine | Asparagine | Leucine 3.Coding and stringing amino acids together is called TRANSLATION! H. Let’s look at the mRNA we transcribed earlier!

14 Phase 2: Translation A. mRNA is shipped out of nucleus for translation B. **Review** Which organelle is in charge of protein synthesis?? (Hint: very tiny little buggers) RIBOSOMES! C. mRNA binds to a ribosome for translation!

15 Steps of Translation 1. mRNA binds to ribosome 2. Ribosome translates the codons on the mRNA 3. This signals a tRNA to bring the correct amino acid 4. tRNA drops off amino acid

16 Steps to Translation cont.: Ribosome moves to next codon Another tRNA comes with next amino acid Amino acids are connected by PEPTIDE BONDS (AA-AA-AA, etc) 8. This continues until all of the mRNA has been read 9. End result: a protein!!!!!!!!!

17 Table is based on mRNA

18 Ex. Name the amino acids that make up the DNA strand: ATC GCT AAG CCT GGC a) mRNA: transcribe (decode) the codons: (remember there aren’t any T’s) - A-U, C-G b) tRNA: bring in the amino acids needed to make the protein molecule: list them in order YOU TRY…..

19 DNA: ATC GCT AAG CCT GGC mRNA: UAG CGA UUC GGA CCG tRNA:AUC GCU AAG CCU GGC AA: XXX - arg - phe - ala - gly

20 DNA in nucleus You have DNA in nucleus (START TRANSCRIPTION) DNA is transcribed to mRNA U’s instead of T’s! mRNA leaves nucleus (START TRANSLATION) mRNA binds to ribosome Ribosome translates codons Translating signals tRNA to bring amino acids Amino acids are bound together by peptide bonds OVERVIEW OF PROTEIN SYNTHESIS

21 Memory Device for Protein Synthesis Transfer RNA brings Transfer RNA brings Amino acids to Amino acids to Ribosome Ribosome Translation Translation Transcription Transcription Unzip the DNA Unzip the DNA Makes Makes Messenger RNA Messenger RNA