Question

Answer all the listed question. Provide reasoning for the identified correct answer. Also, give reasoning for incorrect answer.

Failure to follow the above instructions will result in a thumbs down.

20. A common type of DNA damage from UV light results in ___.

a) bulky adducts

b) cross linked complementary strands

c) intrastrand crosslinks

d) free radicals

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23) Bacterial recombinational repair is activated when damaged DNA has escaped mismatch repair and the distortion disrupts the process of replication. The ___ protein is responsible for this repair mechanism.

a) DNA POII

b) RecA

c) Topoisomerase

d) Ligase

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25) Which of the following is false regarding mis-match repair?

a) It is initiated by specific proteins that function in sequential steps, not as a singular large complex

b) It is the same mechanism as recombination repair

c) It involves DNA ligase

d) It involves DNA polymerase 5’ to 3’ activity

Answer 1

20) b) cross linked complementary strands

UV rays are non-ionizing radiation, such as radio waves, heat and light, which are much less harmful because the rays carry much less energy. Not like other non-ionizing radiation, ultraviolet -B(UVB) light from the sun, can cause mutations in DNA. It does this by causing pyrimidine dimers to form.UVB light causes thymine base pairs next to each other in genetic sequences to bond together into pyrimidine dimers, a disruption in the strand, which reproductive enzymes cannot copy.

23) b) RecA

The SOS response is a global response to DNA damage in which the cell cycle is arrested and DNA repair and mutagenesis are induced. The system involves the RecA protein (Rad51 in eukaryotes)

25) a) It is initiated by specific proteins that function in sequential steps, not as a singular large complex