The first step in base excision repair requires the action of this type of enzym

Question

The first step in base excision repair requires the action of this type of enzyme. A. DNA glycosylase B. AP endonuclease C. DNA polymerase D. DNA ligase E. RecA Which of the following would be the most likely outcome of a neutral in the DNA glycosylase gene? A. Shift of the reading frame will cause a nonfunctional protein to be translated. If this is the only DNA glycosylase gene, the cell will likely die. B. The function of the glycosylase gene is restored and functional glycosylase is produced. C. A stop codon is introduced in the protein coding sequence. D. Recombination and base excision repair is disabled because one of the proteins is no longer functional. This could be the result of many different kinds of changes at the nucleotide level. E. The amino acid sequence of the enzyme is changed, but there is no effect on the DNA repair pathway. Chi sites were named Chi (Crossover Hotspot Instigator) long before the molecular nature of Chi and its mechanism were known. Based on what you understand so far in Molecular Biology which one of the following mechanisms might stimulate homologous recombination? A. chi stimulates recombination to its left so a left acting exonuclease might interact with the Chi site B. The tau protein directs DNA polymerase to bind at the Chi site. C. Homology-directed DNA repair mediated by specific pairing of the broken leg with its homologous sequences on the intact arm is followed by replication restart at the resulting D-loop. D. The phage enters the cell and undergoes a lytic cycle increasing the number of phage in the process. E. Binding of a protein to chi may distort it such that it is a better substrate for the binding of RecA. Mustard gas is an alkylating agent, and can modify bases by adding groups to nitrogenous bases. Which of the following processes would most likely repair the damaged DNA caused by mustard gas exposure of World War soldiers during the third battle of Ypres? A. Ms. Scarlett in the library with the lead pipe. (By not choosing this answer, you aver that you are not totally Clueless) B. Direct repair C. Base addition by thymine dimer repair D. SOS repair E. Nucleotide excision repair

Explanation / Answer

7. The evolutionary pathway that is considered to be the workhorse repair mechanism of the cell is termed as base excision repair. The base excision repair is involved in the correction of various forms of spontaneous hydrolytic decay products in the DNA. The base excision repair mechanism involves various steps. The enzyme involved in these steps are a collection of DNA glycosylases enzyme.

Q. The first step in base excision repair requires the action of this type of enzyme.

Option A. DNA glycosylases is the correct answer.

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