1. Structure Types of RNA Transcription

2.  =RiboNucleic Acid

3.  Polymer  Single stranded  Monomers  Nucleotides

4.  Monomers made of 3 parts each:  Phosphate Group  Ribose Sugar  1 of 4 nitrogen bases  C, A, G, and U!  U = Uracil  No Thymine!

5.  Pyrimidine-why?  Pairs with adenine

7. 1. Messenger RNA (mRNA)  “Records” information from the DNA in the nucleus and transports it out of the nucleus to the ribosomes

8. 2. Transfer RNA (tRNA)  Delivers amino acids to site of protein synthesis (ribosomes) 3. Ribosomal RNA (rRNA)  Helps with ribosome structure; function not entirely understood  We will not go into detail on these second 2 until next week!

9.  DNA is at risk of being damaged if it leaves the nucleus  The info in DNA is copied into mRNA  mRNA is able to leave nucleus and travel to ribosomes (site of protein synthesis)

10.  It brings amino acids to ribosomes to form protein strand.

11.  Transcription  4 Steps (similar to replication)  What is different between transcription and DNA replication?

12. 1. DNA is “unzipped” (HELICASE) 2. Match correct nucleotides according to base pair rules *On only one side of the DNA (RNA POLYMERASE) *U’s not T’s!

13. 3. Bonding-covalent bonds form between sugar and phosphates *Why don’t the hydrogen bonds remain? 4. Transcription occurs until a “stop sign” is reached and the mRNA strand is complete Transcription Animation

14.  3 Nitrogen bases represents 1 CODON = 1 AMINO ACID  64 possible codons  3 “stop” codons  61 code for amino acids (20 possibilities)  1 codes to start = AUG = methionine  Code is universal – codons represent the same amino acid in all organisms

16.  Use your codon chart to answer the following:  1. How many different codons code for valine?  2. The codon CGU is for which amino acid?  3. What are the codons for the three “stops”?  4. What are the first 3 amino acids for this strand of mRNA?