Chapter 11b   (pages 479-505)
An Introduction to the Control of
Gene Expression in Eukaryotes
Humming birds

 


Flower 2

 1. Differences between prokaryotic and eukaryotic Gene Expression.

 List of the 7 differences between eukaryotes and prokayotes (outlined on page 480 in your text).

Table 13-8 from Griffiths et al., 1996
 
 
 

Flower bar 12
 
 

2. The "Central Dogma" revisited.

Remember that in eukaryotic cells, transcription occurs in the nucleus, and the mRNA must be exported to the cytoplasm for translation.

Figure 13-36 from Griffiths et al., 1996

 

In eukaryotes, the mRNA is modified at both ends - the 5' end is "Capped" with a modified GTP, and to the end is added a long "tail" of poly(A) (usually greater than 150 A's are added).  This figure is taken from "The Biology Place"; you can click on it for a link there.

Link to The Biology Place

 

Once again (this is a review) - in bacteria, transcription and translation take place at the same time...

Figure 13-48a from Griffiths et al., 1996
 

 In Eukaryotes, the process is a bit more complicated....
Figure 13-48b from Griffiths et al., 1996




Flower bar 15
3. Transcription in Eukaryotes

In bacteria, all mRNA is made from the same RNA polymerase.  However, in eukaryotes, there are THREE DIFFERENT RNA polymerases: The Eukcaryotic polymerases are much more complex than E.coli RNAP.  This figure (Figure 13-35 from Griffiths et al., 1996) compares the different subunits for eukaryotic RNA Polymerases with that of E.coli RNAP.
Figure 13-35 from Griffiths et al., 1996


Flower bar 20

In eukaryotes, the RNA is processed at both ends before it is spliced.
Link to The Biology Place

 
RNA processing





Flower bar 25

There are 4 different types of proteins which must form a complex for initiation of transcription in eukaryotes.
Figure 18-47
 

Flower bar 28
 
 

Eukaryotic mRNA splicing
hit "reload" to see the animation

Figure 13-39 from Griffiths et al., 1996
 
 

Figure 13-38a from Griffiths et al., 1996
 

Figure 13-38b from Griffiths et al., 1996
 
 

Figure 13-40 from Griffiths et al., 1996

Figure 13-41 from Griffiths et al., 1996

Eukaryotic mRNA splicing

Eukaryotic mRNA splicing
hit "reload" to see the animation



4. Eukaryotic DNA-binding protein motifs

To know some of the different DNA-binding domains of transcription factors:
            a. Helix-turn-helix
            b. homeotic box
            c. zinc fingers
            d. leucine zipper
            e. helix-loop-helix
 
 

Flower 34

Back to the Genetics Syllabus