1. Do Now: Imagine you have an original Michaelangelo painting
Do Now: Imagine you have an original Michaelangelo painting. What would you do with it? How would you prevent it from getting damaged? Why are we talking about paintings at all???

2. DNA Transcription and Translation

3. What is the major job of DNA? How does it do that job?
Form proteins
Store instructions in DNA
Copy instructions to more DNA or RNA
Transmit by translating instructions to amino acid (aa) chain

4. Do DNA and RNA look the same?
Several types
Single stranded
Ribose Sugar
A, C, G, U
Can leave nucleus
DNA
Double stranded
Deoxyribose Sugar
A, C, G, T
Isolated in nucleus

5. ~ 3 Types of RNA ~ mRNA (messenger) – carry DNA info to cytoplasm
rRNA (ribosomal) – attach to mRNA, use info to assemble aa’s in correct order
tRNA (transfer) – transports aa’s to ribosome to assemble proteins

6. How do we get from DNA to RNA???
Transcription!!!
Process of getting info in DNA out of nucleus to cytoplasm
RNA copy made in nucleus
mRNA carries info

7. Steps of Transcription
Enzyme helicase unzips DNA

8. RNA polymerase pairs RNA nucleotides with complementary bases on DNA template strand (U’s instead of T’s)

9. Completed mRNA strand breaks away
DNA rezips
Mature mRNA has a cap and tail (protects); all unused parts of message are edited out
mRNA leaves through nuclear pore
mRNA enters cytoplasm
Who will mRNA meet?

10. How do we now get to protein assembly???
TransLATION!!!
Transcribe vs. Translate
*Rewriting in *Converting one different form language into
(language) another

11. A little about protein language…
What are the building blocks of proteins?
AMINO ACIDS!!
Remember: 20 different amino acids
aa’s coded for by THREE nucleotides –codons
4 bases, 3 per codon: 43 = 64 total possible combinations

12. Why don’t these numbers match? 20 amino acids, 64 options??
WOBBLE
In case of mistakes in DNA, close combinations can result in replacement of same amino acid

13. Do all organisms have same code? Why or why not???
ALL organisms share same code
Most codons code for amino acids
START codon (AUG) - Methionine
STOP codons (UGA, UAA, UAG) – end protein production

14. Review repeats in the code, start codon, & stop codons

15. Steps of Translation
Ribosomes (rRNA) attach to mRNA carries code  tRNA’s carry amino acid and have anticodon complementary to mRNA

16. Protein production starts when START (AUG) is coded for

17. Ribosome slides along mRNA in 3’s (in frame) and tRNA brings matching aa’s

18. aa’s joined by dehydration synthesis to form peptide bond; tRNA released

19. Process continues until STOP codon is reached

21. ** Central idea of cellular and molecular biology **
Gene Expression
** Central idea of cellular and molecular biology **
DNA → RNA → amino acid → protein chain

22. Interactive Gene Expression Activity