Molecular Biology

Thought Questions for Exam 2

Hao Nguyen

 

1.   What is the role of DNA ligase during DNA repair?  What would happen to DNA replication if a cell is incapable of synthesizing this enzyme?

 

2.   Name and describe all the different types of DNA mutations discussed in class.  What caused the formation of these mutations?  What would happen to cellular           functions if these mutations were left unrepaired?

 

3.   Name and describe the function(s) of all types of repair system discussed in class.  Name and describe the function(s) of proteins/enzymes/molecules that are involved in each repair system.  What would happen to the particular DNA repair system if one of these proteins/enzymes/molecules were absent?

 

4.   Why are there so many different types of repair system within a cell?  What would happen to cellular functions if one or more DNA repair systems were nonfunctional?  Why do repair systems sometimes induce additional DNA mutations?  Is this intentional or inadvertent? 

 

5.   What are response elements?  What are consensus sequences?  Where are they located?  What are their functions?  What are transcription factors?  What are their        functions?

 

6.   What is/are the function of the MRE11/RAD50/XRS2 complex?

 

9.   What is the function of a promoter?  Where is a promoter located?  What is the function of a core promoter?  Where is a core promoter located?

 

10.  What are enhancers and silencers?  Where are they located?  What are their functions?

 

11.  Describe the initiation of transcription.  Name and describe the function(s) of all enzymes, molecules, and structures that are involved in each process.

 

12.  What are RNA polymerases?  Where do they bind?  What are their functions?

 

13.  Why do eukaryotic cells need to undergo co-transcriptional modifications?  Name and describe the function(s) of all the different co-transcriptional modifications.  Name and describe the function(s) of all enzymes, molecules, and structures that are involved in each process.

 

14.  What is the difference between a Primary (or Pre-mRNA) transcript and a mature mRNA?  Where is each found?  What is the relationship between the two?

 

15.  What are heterogeneous nuclear RNA’s?  Where are they found?

 

16.  What is a spliceosome?  What is a small nuclear RNA?  What is a small nuclear ribonucleoprotein (or snRNP)?  Name examples of snRNP's and describe their functions.  What is a ribozyme?

 

17.  How is transcription terminated in a eukaryotic cell?  Describe the process of Polyadenylation.

 

18.  What is meant by upstream and downstream in Molecular Biology?

 

19.  What is the direction of mRNA synthesis?  What is the direction of the template used?

 

20.  What is RNA interference?  Describe the mechanism of this process.  Why is this process needed in the eukaryotic cell?