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Ch. 15 - Gene Mutation, DNA Repair, and Transposition
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All textbooksKlug 12th EditionCh. 15 - Gene Mutation, DNA Repair, and TranspositionProblem 22

Chapter 15, Problem 22

The SOS repair genes in E. coli (discussed in Chapter 15) are negatively regulated by the lexA gene product, called the LexA repressor. When a cell's DNA sustains extensive damage, the LexA repressor is inactivated by the recA gene product (RecA), and transcription of the SOS genes is increased dramatically. One of the SOS genes is the uvrA gene. You are a student studying the function of the uvrA gene product in DNA repair. You isolate a mutant strain that shows constitutive expression of the UvrA protein. Naming this mutant strain uvrAᶜ, you construct the diagram shown above in the right-hand column showing the lexA and uvrA operons: Outline a series of genetic experiments that would use partial diploid strains to determine which of the two possible mutations you have isolated.

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Hi everyone and welcome to today's video. So blank is a mechanism that corrects D. N. A. That is replicating throughout the cell cycle. Whereas blank is a pathway that corrects D. N. A. That is continuously being damaged by UV radiation radiation and mutations now in order to solve this problem, we are going to think about it in the following way. While D. N. A. Is being replicating we have the addition of these nucleotides into the strand. However, if we want to fix these errors that appear on the strand as DNA is replicating, we're going to be using a technique called base excision repair in which the basis in the DNA strands are going to be removed and replaced by correct basis. Whereas this blank is going to be occupied by nucleotide excision repair which is a technique that is used to repair or replace and repair Areas of up to 30 basis long. So these are bigger mutations or bigger errors that can be brought about due to UV radiation radiation and mutations because of this. The correct answer choice is going to be answer choice A So base excision repair is a mechanism that corrects DNA that is replicated throughout the cell cycle. Whereas nucleotide excision repair is a pathway that corrects DNA that is continuously being damaged by radiation and mutations. I really hope this video helped you and I have to see you on the next one
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