DNA Repair

Today we had an activity which goal is to improve class participation (and preparation). After doing a quick review of last class, based on the replication "fork" figure (see entry on Wednesday October 22nd - 'DNA replication machinery'), students prepared a 1-2 page essay on today's topic: DNA repair. Students were allowed (and encouraged) to consult the textbook, discuss topics, and ask questions.

The essay will be worth 10 points (to be added to the quiz scores)

Material covered can be found in pages 295-304. Main topics to consider for the exam are:

• Importance of DNA repair
• Repair of the double helix
• Pathways of DNA repair
• DNA polymerases specialized on DNA repair
  
• Repair of double strand breaks
• Effect of DNA repair on the cell cycle

Reading for tomorrow: Control of gene expression (p 411-454... don't freak out. Not every single word will be covered. But read the whole thing if possible)

Quiz #11 Q&As

1. What is a replication fork?
Enzyme induuced 'y' shape conformation of the DNA replicaiton helix

2. What does DNA polymerase do?
It synthesizes mRNAs based on molecualr infromtion

3. What does DNA primase do?
It binds a small RNA promer to the template strand of DNA so the polymerase can start extending the sequence

4. What is DNA repair?
Mechanisms to correct post-proofreading DNA changes, performed by a variety of enzymes

5. How are DNA repair and proofreading different?
Proofreading is done only by some polymerases. DNA repair involves many enzymes

6. What are Okazaki fragments? (bonus: 3 points)
During DNA replication the short fragments of DNA resulting from replication of the lagging strand taking place in the opposite direction to that in which the replication fork opens. They are later stuck together by a DNA ligase to form a continuous strand

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