Skip to main content
Ch. 11 - Gene Mutation, DNA Repair, and Homologous Recombination
Sanders - Genetic Analysis: An Integrated Approach 3rd Edition
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172당신이 사용하는 게 아니라요?교과서 변경
11장, 문제 6c

Ultraviolet (UV) radiation is mutagenic.
Identify and describe two DNA repair mechanisms that remove UV-induced DNA lesions.

검증된 단계별 안내
1
Understand that UV radiation can cause DNA damage, such as the formation of pyrimidine dimers (e.g., thymine dimers), which distort the DNA structure and interfere with replication and transcription.
Learn about the first DNA repair mechanism: nucleotide excision repair (NER). This process involves the recognition of the distorted DNA helix, excision of the damaged segment, and synthesis of a new DNA strand using the undamaged strand as a template. The key steps include: (1) damage recognition by proteins, (2) excision of a short single-stranded DNA segment containing the lesion, (3) DNA polymerase filling the gap, and (4) DNA ligase sealing the nick.
Explore the second DNA repair mechanism: photoreactivation. This is a direct repair process where the enzyme photolyase binds to UV-induced pyrimidine dimers and uses energy from visible light to break the covalent bonds between the dimerized bases, restoring the original DNA structure.
Compare the two mechanisms: NER is a general repair pathway that can fix a wide range of bulky DNA lesions, while photoreactivation is specific to UV-induced pyrimidine dimers and requires light activation.
Consider the biological significance: These repair mechanisms are crucial for maintaining genomic integrity and preventing mutations that could lead to diseases such as cancer.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
5m

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

UV-Induced DNA Lesions

Ultraviolet (UV) radiation can cause specific types of DNA damage, primarily forming pyrimidine dimers, such as thymine dimers. These lesions distort the DNA structure, leading to replication errors and potential mutations if not repaired. Understanding the nature of these lesions is crucial for comprehending how cells respond to UV damage.
추천 영상:
가이드 코스
04:29
Induced Mutations

Nucleotide Excision Repair (NER)

Nucleotide Excision Repair (NER) is a critical DNA repair mechanism that recognizes and removes bulky DNA lesions, including those caused by UV radiation. The process involves the excision of a short single-stranded DNA segment containing the damage, followed by DNA synthesis to fill the gap. NER is essential for maintaining genomic stability and preventing mutations.
추천 영상:
가이드 코스
05:44
Repair Pathways

Photoreactivation

Photoreactivation is a light-dependent DNA repair mechanism that directly reverses UV-induced pyrimidine dimers. This process involves the enzyme photolyase, which binds to the dimer and, upon absorbing blue light, cleaves the bond between the pyrimidines, restoring the DNA to its original state. This repair pathway is particularly effective in organisms exposed to sunlight.
관련 실천
교과서 질문

Researchers interested in studying mutation and mutation repair often induce mutations with various agents. What kinds of gene mutations are induced by

Chemical mutagens? Give two examples.

381
views
교과서 질문

In March 2011 an earthquake measuring approximately 9.0 on the Richter scale struck Fukushima, Japan. Several nuclear reactors at the Fukushima Daichii Nuclear Power Plant were damaged, and nuclear core meltdown occurred. A massive release of radiation accompanied damage to the plant, and 5 years later the incidence of thyroid cancer in children exposed to the radiation was determined to be well over 100 times more frequent than expected without radiation exposure. DNA damage and mutations resulting from radiation exposure are suspected of causing this increased cancer rate. What gene discussed in this chapter might be responsible for pausing the cell cycle of dividing cells long enough for radiation-induced damage to be repaired in cells?

414
views
교과서 질문

Researchers interested in studying mutation and mutation repair often induce mutations with various agents. What kinds of gene mutations are induced by

Radiation energy? Give two examples.

430
views
교과서 질문

Ultraviolet (UV) radiation is mutagenic.

What kind of DNA lesion does UV energy cause?

913
views
교과서 질문

The effect of base-pair substitution mutations on protein function varies widely from no detectable effect to the complete loss of protein function (null allele). Why do the functional consequences of base-pair substitution vary so widely?

607
views
교과서 질문

Ultraviolet (UV) radiation is mutagenic.

How do UV-induced DNA lesions lead to mutation?

789
views