1. RNA Structure and Transcription
Joyce Fiel
Matt Speir
Alliver Verzon
Shann Bunggay

2. Overview RNA Structure Types of RNA The Genetic Code [Codons]
mRNA
tRNA
rRNA
The Genetic Code [Codons]
Transcription
Initiation
Elongation
Termination

3. What is RNA? RNA = Ribo Nucleic Acid Single Strand
Similar to DNA but pyrimidyne base, uracil replaces thymine and ribose replace deoxyribose
Five-carbon sugar
Nucleotides: Guanine, Cytosine, Adenine, Uracil
Backbone made of alternating ribose and phosphate groups
Other bases: thymine, pseudouridine and methylated cytosine and guanine.

4. Types of RNA Messenger RNA (mRNA)
Transcribed from DNA template
Carries coding information to ribesome (site of protein synthesis)
Moves DNA information to translation machinery
Always has 5’ cap between two modified nucleotides
Most have poly-Adenosine tail at 3’ end
Provides templates used to make amino acids

5. Types of RNA Transfer RNA (tRNA)
Short RNA molecule
also called anticodon or adaptor molecule. 
One or more tRNAs for each amino acid
3’ end of tRNA attaches to amino acid
Decodes information in DNA
More than 20 different tRNA molecules
Each have between nucleotides
4 arms, 3 loops

6. Types of RNA Ribosomal RNA (rRNA)
Most abundant – 80% of RNA
Building blocks of ribosomes
Combines with proteins from cytoplasm to make ribosomal subunits
3’ end attaches to an amino acid
Several roles in protein synthesis
Catalytic role
Recognition role
Structural role

7. Dictionary of the Genetic Code

8. Transcription

9. Transcription Animation

10. What is Transcription? first step in protein synthesis
DNA-directed synthesis of RNA
Utilizes enzyme called RNA Polymerase
Takes place in 3 stages
Initiation
Elongation
Termination

11. Stage I: Initiation and RNA Polymerase Binding
Takes place in promoter region of DNA
RNA polymerase attaches, transcription initiated
DNA unzips
Binding polymerase is different between prokaryotes and eukaryotes
Transcription factors required
Results in transcription initiation complex
TATA box : crucial promoter DNA sequence

12. Stage II: Elongation of the RNA Strand
DNA continues to unwind
Takes place in coding region of DNA
10-20 DNA bases exposed to pair with RNA nucleotides
Enzyme adds nucleotides to 3’ end of RNA molecule
DNA double helix reforms, RNA peels away
Transcription in eukaryotes- 60 nucleotides per second
Multiple RNA polymerase can transcribe a single gene simultaneously

13. Stage III: Termination of Transcription
Transcription stops when RNA hits the terminator DNA sequence
RNA sequence makes actual termination signal (stop codon)
In prokaryotes: transcriptions stops at end of termination signal
In eukaryotes: mRNA is cut free from enzyme about nucleotides after termination signal (AAUAAA sequence in pre-mRNA)

14. Works Cited
Trusty Bio book
Cliffnotes