Loading...

BIO101A: Introduction to Molecular and Cellular Biology

Unit 5: Central Dogma of Molecular Biology  

Francis Crick (one of the scientists that shared the Nobel Prize for discovering the double-helix nature of DNA) first coined the term “central dogma” of molecular biology in 1958 to describe one of the most important pathways in biology. This theory states that the information for life flows in a single direction – from genes (DNA) to RNA to protein – and that, in effect, DNA contains the information for life and creates diversity in life. This discovery has fueled much of the biomedical research that has taken place over the past few decades. It has led us to invest billions of dollars in the Human Genome Project (a project that aims to identify every single human gene) and sparked the biotechnology industry, which enabled us to transplant genes from one organism to another and create glow-in-the-dark mice, among other things. (This unit is covered in great detail in BIO311: Molecular Biology, if you want to learn more about it.)

Unit 5 Time Advisory
Completing this unit should take you approximately 17.75 hours. 

☐   Unit 5: 3.5 hours
 
☐   Subunit 5.1: 0.75 hours
 
☐   Subunit 5.2: 1 hour
 
☐   Subunit 5.3: 2.75 hours
 
☐   Subunit 5.4: 6.25 hours   
 
☐   Subunit 5.5: 3 hours
 
☐    Assessment: 0.5 hours

Unit5 Learning Outcomes
Upon successful completion of this unit, you will be able to:

  • explain how information is encoded in the DNA;
  • describe how information is copied from the DNA into mRNA;
  • describe how mRNA is then used for protein synthesis;
  • explain the difference between transcription, translation, and protein synthesis, being sure to list where each process occurs in the eukaryotic cell;
  • compare the differences and similarities between DNA and RNA;
  • explain posttranslational processing and where it occurs in the eukaryotic cell;
  • describe the role of lactose in regulating transcription of the lac operon; and
  • explain the function of exons, introns, enhancers, and silencers in eukaryotic gene regulation.

  • Lecture: YouTube: University of California, Berkeley: Webcast.Berkeley: “Transcription,” “The Genetic Code and Translation,” “Prokaryotic Gene Regulation,” and “Eukaryotic Gene Expression and Regulation”

    Link: YouTube: University of California, Berkeley: Webcast.Berkeley: “Transcription,”“The Genetic Code and Translation,”“Prokaryotic Gene Regulation,” and “Eukaryotic Gene Expression and Regulation” (YouTube)

    Instructions: Watch these lectures to learn about how biological information travels from DNA to protein. You will also learn how this biological information is regulated.

    Watching these lectures and taking notes should take approximately 3 hours and 30 minutes.

    Terms of Use: The above video is reposted from the University of California, Berkeley’s Webcast.Berkeley. This video is released under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Unported License

5.1 The Central Dogma of Molecular Biology   Note: The Central Dogma of Molecular Biology is one of the most important topics in molecular biology! Please don’t be confused by the titles of the resources in this subunit. “The Central Dogma of Molecular Biology” is called “The Central Dogma of Biochemistry” and “The Central Dogma of Biology” by different sources. However, all these names refer to the same dogma.

  • Reading: National Center for Biotechnology Information: Molecular Biology Review: “Central Dogma of Biology: Classic View”

    Link: National Center for Biotechnology Information: Molecular Biology Review: “Central Dogma of Biology: Classic View” (HTML)

    Instructions: Read the entire webpage (but you do not need to click on the hyperlinks). Take particular note of the webpage’s flow diagram. Information flows one way, from DNA to RNA to protein; a protein sequence cannot be reversed to give back its original DNA sequence. Note that this resource is called the “Central Dogma of Biology.” The next resource uses the title “Central Dogma of Biochemistry.” Both refer to the same dogma and important molecular biology concept.
     
    Reading this webpage should take approximately 15 minutes.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: Wiley: “The Central Dogma of Biochemistry”

    Link: Wiley: “The Central Dogma of Biochemistry” (Flash)

    Instructions: Watch the entire animation to understand how the pathway works and how biological information is expressed. Note that information flows one way, from DNA to RNA to protein; a protein sequence cannot be reversed to give back its original DNA sequence.

    Watching this animation and taking notes should take approximately 30 minutes.
     

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

5.2 Transcription   5.2.1 Initiation, Elongation, Termination   - Reading: University of California, Davis: ChemWiki: “RNA-Transcription” Link: University of California, Davis: ChemWiki: “RNA-Transcription” (HTML)

 Instructions: Read this article to understand how transcription
works in eukaryotes and prokaryotes. There are several classes of
RNA polymerase and each has a specific purpose. You should know how
to distinguish between them. Also, the process by which the RNA
polymerase recognizes the start sequence (TATA box and others) is
highly complex, so know the major players.  

 Reading this article and taking notes should take approximately 30
minutes.  

 Terms of Use: This resource is licensed under a [Creative Commons
Attribution-NonCommercial-ShareAlike 3.0 United States
License](http://creativecommons.org/licenses/by-nc-sa/3.0/us/). It
is attributed to the University of California, Davis.

5.2.2 DNA and RNA   - Web Media: Diffen: “DNA vs. RNA”

Link: Diffen: [“DNA vs.
RNA”](http://www.diffen.com/difference/DNA_vs_RNA) (PDF)  

 Instructions: Read and take notes on this table to understand the
major differences between DNA and RNA. Although most life on Earth
uses DNA as the genetic code, some lower life forms like viruses use
RNA as the genetic code. Early life forms on Earth were hypothesized
to have started out using RNA as their genetic code.  

 Reading this table and taking notes should take approximately 30
minutes.  

 Terms of Use: The article above is released under a [Creative
Commons Attribution-Share-Alike License
3.0](http://creativecommons.org/licenses/by-sa/3.0/). It is
attributed to Diffen, and the original version can be found
[here](http://www.diffen.com/difference/DNA_vs_RNA).

5.3 RNA Processing   - Reading: cK-12: “Transcription of DNA to RNA” Link: cK-12: “Transcription of DNA to RNA” (HTML)

 Instructions: Read this webpage. Pay attention to the “Processing
mRNA” section. At the bottom of the paragraph that begins “Splicing
removes introns from mRNA,” you will find a link to a video. Click
on the link and watch the video in that section.  

 Reading this webpage and watching the video should take
approximately 45 minutes.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.
  • Reading: John W. Kimball’s “RNA Editing”

    Link: John W. Kimball’s “RNA Editing” (HTML)

    Instructions: Read the entire webpage and click on the embedded links to understand the different mechanisms of RNA editing.

    Reading this webpage should take approximately 2 hours.

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

5.4 Translation   5.4.1 Initiation, Elongation, Termination   - Reading: cK-12: “Translation of RNA to Protein”

Link: cK-12: [“Translation of RNA to
Protein”](http://www.ck12.org/concept/Translation-of-RNA-to-Protein/) (HTML)


 Instructions: Click and read the “Translation of RNA to Protein:
Discusses Translation in Protein Synthesis” and “Translation of RNA
to Protein: Introduces the Process of Translation of mRNA to Make a
Proteins” [*sic*] sections. These readings cover initiation,
elongation, and termination of protein synthesis, as well as the use
of codons in protein synthesis.  

 Reading these sections and taking notes should take approximately
30 minutes.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

5.4.2 Posttranslational Processing   - Reading: National Center for Biotechnology Information’s Bookshelf: Harvey Lodish, Arnold Berk, et al.’s Molecular Cell Biology, 4e: “Post-Translational Modifications and Quality Control in the Rough ER”

Link: National Center for Biotechnology Information’s Bookshelf:
Harvey Lodish, Arnold Berk, et al.’s *Molecular Cell Biology, *4e:
[“Post-Translational Modifications and Quality Control in the Rough
ER”](http://www.ncbi.nlm.nih.gov/books/NBK21741/)(HTML)  

 Instructions: Read this webpage to learn about posttranslational
modifications performed on proteins after exiting the ribosome.  

 Reading this webpage and taking notes should take approximately 1.5
hour.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

5.5 Regulation of Gene Expression   5.5.1 Prokaryotic Regulation   - Reading: cK-12: “Prokaryotic Gene Regulation”

Link: cK-12: [“Prokaryotic Gene
Regulation”](http://www.ck12.org/concept/Prokaryotic-Gene-Regulation/?ref=%2Fconcept%2FProkaryotic-Gene-Regulation%2F)(HTML)  
    
 Instructions: Read this webpage to understand what operons are and
how the lac operon functions. Click on and watch the video in the
“Lac Operon” section. Click on the link in Practice I for more
information about the lac operon, and then click on the link in
Practice II for an interactive animation of how the lac operon
functions.  
    
 Reading this webpage and exploring the links should take
approximately 1 hour.  
    
 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.
  • Web Media: YouTube: drsalomon123’s “Trp Operon”

    Link: YouTube: drsalomon123’s “Trp Operon” (YouTube)

    Instructions: Watch this video and note how repression functions to control prokaryotic gene transcription.

    Watching this video and taking notes should take approximately 15 minutes.
     

    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Reading: National Center for Biotechnology Information’s Bookshelf: Geoffrey Cooper’s The Cell: A Molecular Approach, 2e: “Transcription in Prokaryotes”

    Link: National Center for Biotechnology Information’s Bookshelf: Geoffrey Cooper’s The Cell: A Molecular Approach, 2e: “Transcription in Prokaryotes” (HTML)

    Instructions: Read the introduction and the “RNA Polymerase and Transcription” section to learn how prokaryotic gene promoters function to initiate transcription and how transcription is terminated.

    Reading this webpage and taking notes should take approximately 1 hour.

    Terms of Use:  Please respect the copyright and terms of use displayed on the webpage above. 

5.5.2 Eukaryotic Regulation   - Reading: cK-12: “Eukaryotic Gene Regulation” (HTML)

**Link:** cK-12: [“Eukaryotic Gene
Regulation”](http://www.ck12.org/biology/Gene-Expression-and-Regulation/lesson/Eukaryotic-Gene-Regulation/) (HTML)  

 Instructions: Read this webpage, and then click on and watch the
two YouTube videos in the text to learn more about TATA boxes and
how genes that regulate transcription are conserved throughout
evolution.  

 Reading this webpage and watching the videos should take
approximately 1 hour.  

 Terms of Use:  Please respect the copyright and terms of use
displayed on the webpage above. 
  • Reading: Professor John W. Kimball’s Biology Pages: “Gene Regulation in Eukaryotes”

    Link: Professor John W. Kimball’s Biology Pages: “Gene Regulation in Eukaryotes” (PDF)

    Instructions: Read this PDF and click on the embedded links to gain an understanding of eukaryotic gene expression regulation. Understand why it is much more complex than prokaryotic regulation.

    Reading this PDF and taking notes should take approximately 3 hours.

    Terms of Use: The linked material above has been reposted by the kind permission of Professor John W. Kimball, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder. 

Unit 5 Quiz   - Assessment: The Saylor Foundation’s “BIO101 Unit 5 Quiz”

Link: The Saylor Foundation’s [“BIO101 Unit 5
Quiz”](http://school.saylor.org/mod/quiz/view.php?id=1343)  

 Instructions: Instructions: Complete this assessment to gauge your
understanding of the topics covered in this unit. The correct
answers will be displayed when you click the “Submit” button.


 Completing this assessment should take approximately 30 minutes.