Difference Between Base Excision Repair and Nucleotide Excision Repair

Excision repair: Damage to one or a few bases of DNA is often fixed by removal (excision) and replacement of the damaged region. In base excision repair, just the damaged base is removed. In nucleotide excision repair, as in the mismatch repair we saw above, a patch of nucleotides is removed.

1. How does nucleotide excision repair differ from base excision repair quizlet?
2. What does nucleotide excision repair?
3. What are the steps of nucleotide excision repair?
4. What is base excision repair mechanism?
5. Which statement is true with respect to mismatch repair and nucleotide excision repair?
6. In which direction does DNA replication take place?
7. Which enzyme is involved in excision repair?
8. What is the most dangerous type of DNA damage?
9. What is the correct definition of excision repair?
10. What is the function of enzyme involved in base excision repair?
11. What is the correct order for the following events in excision repair of DNA?
12. What happens during nucleotide excision repair quizlet?

How does nucleotide excision repair differ from base excision repair quizlet?

Nucleotide-excision repair reverses the chemical reaction that caused the lesion, whereas base-excision repair removes the damaged bases and replaces them with normal ones.

What does nucleotide excision repair?

In nucleotide excision repair (NER), damaged bases are cut out within a string of nucleotides, and replaced with DNA as directed by the undamaged template strand. This repair system is used to remove pyrimidine dimers formed by UV radiation as well as nucleotides modified by bulky chemical adducts.

What are the steps of nucleotide excision repair?

NER occurs in four main steps: (1) DNA-damage recognition, (2) incision on both sides of the DNA lesion and removal of the damaged DNA fragment, (3) gap-filling DNA synthesis, and (4) ligation of open DNA ends.

What is base excision repair mechanism?

Base excision repair (BER) is a cellular mechanism, studied in the fields of biochemistry and genetics, that repairs damaged DNA throughout the cell cycle. It is responsible primarily for removing small, non-helix-distorting base lesions from the genome.

Which statement is true with respect to mismatch repair and nucleotide excision repair?

Which statement is true with respect to mismatch repair and nucleotide excision repair (NER)? Mismatch repair fixes thymine dimers caused by exposure to UV light, while NER fixes errors in DNA replication.

In which direction does DNA replication take place?

DNA synthesis occurs only in the 5' to 3' direction. On the leading strand, DNA synthesis occurs continuously.

Which enzyme is involved in excision repair?

The process of nucleotide excision repair is controlled in Escherichia coli by the UvrABC endonuclease enzyme complex, which consists of four Uvr proteins: UvrA, UvrB, UvrC, and DNA helicase II (sometimes also known as UvrD in this complex).

What is the most dangerous type of DNA damage?

Double-strand DNA breaks—the most dangerous form of DNA damage, which can lead to cancer—don't happen randomly but at specific sites in the genome during replication, the process of DNA making exact copies of itself before cell division.

What is the correct definition of excision repair?

A process whereby cells remove part of a damaged DNA strand and replace it through DNA synthesis using the undamaged strand as a template. The repair of a DNA lesion by removal of the faulty DNA segment and its replacement with a new segment.

What is the function of enzyme involved in base excision repair?

Enzymes that cleave the bond between deoxyribose and a modified or mismatched DNA base are now called DNA glycosylases. Collectively these enzymes initiate base excision repair of a large number of base lesions, each recognized by one or a few DNA glycosylases with overlapping specificities.

What is the correct order for the following events in excision repair of DNA?

What is the correct order for the following events in excision repair of DNA? (1) DNA polymerase I adds correct nucleotides by 5′-to-3′ replication; (2) damaged nucleotides are recognized; (3) DNA ligase seals the new strand to existing DNA; (4) part of a single strand is excised.

What happens during nucleotide excision repair quizlet?

As DNA polymerase synthesizes new DNA, the DNA polymerase finds and corrects misplaced nucleotides. ... What happens during nucleotide excision repair of damaged DNA? Enzymes unwind the DNA, cut out a section on one stand that contains the DNA damage, and resynthesize the section with the correct DNA sequence.