1. Central Dogma
Big Idea 3: Living systems store, retrieve, transmit, and respond to info essential to life processes.

2. Essential Knowledge
3A1: DNA, and in some cases RNA, is the primary source of heritable information.

3. Central Dogma! Protein Synthesis
Genetic info flows from nucleotide sequence in a gene to amino acid sequence in a protein

4. DNA 1 Synthesis of mRNA in the nucleus mRNA NUCLEUS CYTOPLASM
Fig
DNA 1
Synthesis of
mRNA in the
nucleus
mRNA
NUCLEUS
CYTOPLASM
Figure 5.26 DNA → RNA → protein

5. DNA 1 Synthesis of mRNA in the nucleus mRNA NUCLEUS CYTOPLASM mRNA 2
Fig
DNA 1
Synthesis of
mRNA in the
nucleus
mRNA
NUCLEUS
CYTOPLASM
mRNA 2
Movement of
mRNA into cytoplasm
via nuclear pore
Figure 5.26 DNA → RNA → protein

6. DNA 1 Synthesis of mRNA in the nucleus mRNA NUCLEUS CYTOPLASM mRNA 2
Fig
DNA 1
Synthesis of
mRNA in the
nucleus
mRNA
NUCLEUS
CYTOPLASM
mRNA 2
Movement of
mRNA into cytoplasm
via nuclear pore
Ribosome
Figure 5.26 DNA → RNA → protein 3
Synthesis
of protein
Amino
acids
Polypeptide

7. mRNA: Carries info from DNA to ribosome
Types of RNA Involved
mRNA: Carries info from DNA to ribosome

8. Types of RNA Involved
tRNA: Bind specific amino acids and allow info in the mRNA to be translated into a linear peptide sequence.

9. rRNA: functional building blocks of ribosomes (site of translation)
Types of RNA Involved
rRNA: functional building blocks of ribosomes (site of translation)

10. Types of RNA Involved
RNAi:  RNA interference molecules that inhibit gene expression; sometimes destroy mRNA.
2 molecules involved: microRNA and siRNA (small interfering RNA) that regulate gene expression.

11. Transcription Occurs Here! Translation Occurs Here!

12. Transcription DNA  mRNA, made by RNA polymerase II
RNA polymerase binds on promoter (nucleotide), reads DNA from 3’ to 5’
3 stages: Initiation,Elongation, Termination

13. A on DNA complements U on RNA
RULE!
A on DNA complements U on RNA
RNA has no T base!

14. Initiation
Promoters: start RNA synthesis, TATA box is one in eukaryotes
Transcription factors: help binding of RNA polymerase
Completed assembly called a transcription initiation complex

15. Several transcription factors must bind to the DNA before RNA
Fig. 17-8 1
A eukaryotic promoter
includes a TATA box
Promoter
Template 5 3 3 5
TATA box
Start point
Template
DNA strand 2
Several transcription factors must
bind to the DNA before RNA
polymerase II can do so.
Transcription
factors 5 3 3 5 3
Additional transcription factors bind to
the DNA along with RNA polymerase II,
forming the transcription initiation complex.
Figure 17.8 The initiation of transcription at a eukaryotic promoter
RNA polymerase II
Transcription factors 5 3 3 5 5
RNA transcript
Transcription initiation complex

16. Elongation
Transcription progresses at a rate of 40 nucleotides per second in eukaryotes

17. Termination
In bacteria: polymerase stops transcription at end of terminator (nucleotide sequence)
In eukaryotes: polymerase continues transcription after pre-mRNA is cut  polymerase eventually falls off DNA

18. RNA Processing Enzymes modify mRNA
Ex: Addition of poly-A tail on 3’ end and a GTP 5’ Cap
Helps export mRNA and protect from degrading hydrolytic enzymes

19. RNA splicing: removes introns (noncoding), joins exons (coding)
RNA Processing
RNA splicing: removes introns (noncoding), joins exons (coding)

20. Translation
mRNA message gets translated into a protein w/ help of transfer RNA (tRNA)

21. Occurs at Ribosomes
2 ribosomal subunits (large and small) are made of proteins and ribosomal RNA (rRNA)

22. Either free floating in cytoplasm
Ribosomes
Either free floating in cytoplasm

23. Or Attached to Rough Endoplasmic Reticulum
Ribosomes
Or Attached to Rough Endoplasmic Reticulum

24. P Site: holds tRNA that carries growing polypeptide chain
A Site: holds next tRNA that will add a. acid to chain
E Site: holds exit tRNA that doesn’t have an a. acid
Ribosomes

25. Initiation of Translation
mRNA interacts w/ rRNA of ribosome at start codon AUG
mRNA is read in triplets called codons, which encodes a specific amino acid.
tRNA carries the amino acid to the mRNA and ribosome

26. Termination of Translation
Amino acids join to make a peptide chain
Stop codon stops process, release of new peptide chain.

27. Amino Acid Sequences

28. mRNA and Transcription
Big green thing = RNA polymerase

29. Protein Synthesis Videos
NOVA: DNA Secret of Life

30. Prokaryotic Protein Synthesis
Transcription is coupled to translation of the message. Involves mucho energy and also has initiation, elongation, and termination.

31. Phenotypes are determined through protein synthesis!