1. Transcription

2. Central Dogma What is a Dogma? Process of DNA RNA protein
a principle laid down by an authority as incontrovertibly true
Process of DNA RNA protein

3. RNA Structure & Function
Single-strand
found in both nucleus & cytoplasm
Composed of nucleotides
Each nucleotide has 3 parts
Phosphate
5-C sugar--Ribose
4 possible nitrogen bases
Adenine and guanine
Cytosine and uracil (uracil replaces thymine)
Gene Expression
Segment of DNA  codes for a polypeptide

4. Types of RNA (Overview)
mRNA- carries genetic information from the DNA out to ribosomes
rRNA- composes ribosomes, site of protein assembly
tRNA- brings in amino acids to the ribosomes

5. Learning Check! What are the similarities between RNA and DNA?
What are the differences between RNA and DNA?

6. Transcription Transcription Makes RNA from a DNA template
3 phases-initiation, elongation, termination

7. Transcription Initiation RNA polymerase binds to a promoter region
RNA Polymerase unwinds DNA

8. Transcription Elongation
RNA polymerase adds complementary RNA nucleotides

9. Transcription Termination RNA Polymerase reaches termination sequence
DNA rewound
Methyl Cap & poly-A tail added (makes it more stable)

10. Processing Occurs in the nucleus
Both prokaryotic and eukaryotic cells undergo this process
Primary mRNA  mature mRNA

11. Processing
Step 1:
Primary mRNA contains bases complementary to both intron and exon segments of DNA

12. Processing
Step 2:
Intron sequences are removed,

13. Processing
Step 3:
Ribozyme (RNA enzyme) splices exon segments together
com/watch?v=YgmoHt LGb5c
/watch?v=o0BQJbLNYSg

14. Learning Check!
Explain how RNA is modified before leaving the nucleus.
What happens during transcription?
What does RNA polymerase do (several jobs)?