1. Protein Synthesis: Transcription and Translation

2. Proteins DNA codes for protein
A segment of DNA that codes for a specific protein is called a gene
When your body needs a protein, it follows the instructions in DNA on a specific gene to make one.

3. Protein synthesis problem!
Where is DNA, the instructions for proteins located?
In the nucleus

4. Protein synthesis problem!
What inside of the cell makes proteins?
Ribosomes
Where are ribosomes located?
Ribosomes in the cytosol

5. DNA to Protein Problem DNA cannot leave the nucleus
Protein factories (ribosomes) are NOT in the nucleus and they cannot get into the nucleus

6. How does your body know how to make proteins?
RNA to the rescue
RNA carries DNA’s instructions
The flow of genetic information:
DNA to RNA to Protein

7. Protein Synthesis Two processes of protein synthesis Transcription
Translation

8. Transcription Transcription rewrites DNA into RNA
occurs in the nucleus
makes mRNA
start site
nucleotides
transcription complex

9. Transcription steps 1a. DNA separates
2b. Complementary RNA bases are correctly paired to one side of the DNA
start site
nucleotides
transcription complex
DNA

10. Transcription steps 3c. mRNA separates from DNA 4d. DNA reforms
5e. mRNA leaves the nucleus
RNA

11. Transcription mRNA = messenger RNA
mRNA carries the instructions for making a protein from the DNA to the protein factories (ribosomes)
DNA

12. Practice Transcribe the left side of this strand of DNA
A-T RNA base pairing rules
C-G A - U C - G
C-G
T-A
G-C

13. Practice
DNA
Left Side
mRNA transcript
A-T A
C-G C
T-A T
G-C G

14. Practice
DNA
Left Side
mRNA transcript
A-T A U
C-G C G
T-A T
G-C

15. Transcribe the left side of this DNA strand
mRNA transcript
T-A T
A-T A
G-C G

16. Transcribe the left side of this DNA strand
mRNA transcript
T-A T A
A-T U
G-C G C

17. Protein synthesis
1. Transcription
2. Translation

18. Transcribe this DNA strand
T A C G A A T C G A C T

19. Transcribe this DNA strand
T A C G A A T C G A C T
A U G C U U A G C U G A

20. How to translate Divide your mRNA sequence into groups of three
A U G C U U A G C U G A

21. How to translate Divide your mRNA sequence into groups of three
A U G / C U U / A G C / U G A

22. How to translate 3 nitrogen bases = a codon (a word)
3 nitrogen bases = 1 amino acid
Many amino acids = a protein
Use the genetic code chart to translate into the correct amino acid sequence

23. Genetic code chart

24. How to translate
A U G / C U U / A G C / U G A
AUG =
CUU =
AGC =
UGA =

25. How to translate A U G / C U U / A G C / U G A
AUG = Met (Start translation)
CUU =
AGC =
UGA =

26. How to translate A U G / C U U / A G C / U G A
AUG = Met (Start translation)
CUU = Leu
AGC =
UGA =

27. How to translate A U G / C U U / A G C / U G A
AUG = Met (Start translation)
CUU = Leu
AGC = Ser
UGA =

28. How to translate A U G / C U U / A G C / U G A
AUG = Met (Start translation)
CUU = Leu
AGC = Ser
UGA = Stop translation

29. How to translate A U G / C U U / A G C / U G A
AUG = Met (Start translation)
CUU = Leu
AGC = Ser
UGA = Stop translation
Amino acid sequence = Met - Leu - Ser - Stop
A bunch of amino acids = a protein