1 reverses damage to DNA caused by cyclobutane pyrimidine d

1. ___________ reverses damage to DNA caused by cyclobutane pyrimidine dimer formation.  

Lysozyme

Photolyase

DNA polymerase III

LexA

none of the above

2. Proteins such as O⁶-alkyl-guanine DNA alkyltransferase I, which lose activity after acting only one time, are called _________________.  

mortality enzymes

suicide enzymes

necrosis enzymes

zombie enzymes

none of the above

3. In E. coli, which DNA polymerase is primarily responsible for filling in the gaps in the DNA generated during base excision repair?  

DNA polymerase I

DNA polymerase II

DNA polymerase IV

DNA polymerase V

none of the above

4. In eukaryotes, which DNA polymerase is primarily responsible for filling in the gaps in the DNA generated during base excision repair?  

DNA polymerase

DNA polymerase

DNA polymerase

DNA polymerase ö

DNA polymerase

5. High energy electromagnetic radiation includes which of the following?  

ultraviolet light

x-rays

gamma rays

two of the above

all three of the above

6. Which of the following types of damage to DNA cannot be caused by x-rays and gamma rays?  

deletions

duplications

insertions

translocations

inversions

Solution

(1) photolyase

Cyclobutane pyrimidine dimer (CPD) photolyase repairs ultraviolet-B-induced CPDs

(2) suicide enzyme

Proteins such as O6-alkyl-guanine DNA alkyltransferase I, which lose activity after acting only one time, are called suicide enzyme

(3) DNA polymerase I

DNA polymerase 1 is involved in excision repair with both 3\'-5\' and 5\'-3\' exonuclease activity. It also fills the gaps in the DNA generated during base excision repair.