Cornell University BIOG 1105-1106
Unit 2: Demos

Objective 3:

Promoter strength (3c)
What Is The Role Of RNA Polymerase In Transcription? What are promoter sites?
RNA polymerase termination signal in prokaryotes (3d)
Zebrafish Glow in the Morning - firefly gene linked to biological clock promoter helps researchers understand circadian rhythms. (optional)

Objective 12:

Transposons: Spam from the Dark Ages (optional)

Objective 13:

Recombinant DNA and gene cloning
Give the dog a clone (optional)

Objective 14

PCR (supplementary):

What the heck is PCR?
Principle of PCR
Check out the book Making PCR by Paul Rabinow. Call # QP606.D46 R33x 1996 at either Olin or Uris.
PCR schematic
Diagram of the PCR reactions

Objective 15:

Gel electrophoresis (supplementary):

Southern Blot Schematic

Objective 16:

Genome mapping (supplementary)
A physical map of the human Y chromosome (optional)

Objective 17:

DNA profiling (supplementary):

Disclosure of variation - Now that the sequence of the human genome is almost complete, the human genomics community is turning its attention towards what, genetically speaking, makes people different.
Saddam's DNA test a fast job (Wired News)
DNA profiling - Mallory, Lost on Everest (Nova Online)
also see the BIOG 1105-1106 DNA Lab page

Optional Supplementary Material:

Gene Therapy
RNA vs DNA
Origin of tRNA and rRNA

Genetic engineering:

Flower Power Takes on Land Mines (story with image)
Bacteria modified to help make missile fuel
Molecular Biology Tutorials
In Situ Hybridization diagram

What Is The Role Of RNA Polymerase In Transcription?

RNA polymerase is a complex enzyme that plays multiple roles in the process of transcription:

  1. It searches DNA for initiation sites, that is, promoter sites. E. coli DNA, for instance, has about 2,000 promoter sites in its 4 X 106 base pairs.
  2. It unwinds a short stretch of double-helical DNA to produce a single-stranded DNA template from which it takes instructions.
  3. It selects the correct ribonucleoside triphosphate and catalyzes the reaction in which the ribonucleotides are added to the 3' –OH end of RNA.

What Are Promoter Sites?

DNA contains initiation sites called promoters that specifically bind RNA polymerase and determine where transcription begins. In prokaryotic cells, two sequences on the 5' (upstream) side of the first nucleotide to be transcribed are important (See Fig. A). One has the consensus sequence TATAAT and is centered at –10 (10 nucleotides on the 5' side of the first one transcribed, which is denoted by +1). The other, the –35 region, has the consensus sequence TTGACA.

Eukaryotic genes encoding proteins have promoter sites with a TATAAA consensus sequence centered at about –25 (Fig. B). Many eukaroytic promoters also have a CAAT box centered about –75. Transcription of eukaryotic genes is also facilitated by enhancer sequences that can be quite distant from the start site.

Download Printable (PDF) Version

Back to Main Menu / Previous Objective / Next Objective /

© 2010 | BIOG 1105-1106
Back to Top | Home