Genetics DNA Repair Mechanisms
37 flashcards covering Genetics DNA Repair Mechanisms for the GENETICS Genetics Topics section.
Genetics DNA repair mechanisms refer to the processes by which cells identify and correct damage to the DNA molecules that encode their genomes. The National Institutes of Health (NIH) provides foundational guidelines on these mechanisms, emphasizing their critical role in maintaining genomic stability and preventing diseases such as cancer. Understanding these repair pathways is essential for genetics professionals, as they relate directly to cellular function and therapeutic approaches.
In practice exams and competency assessments, questions on DNA repair mechanisms often assess knowledge of specific pathways, such as nucleotide excision repair or homologous recombination. These questions may present scenarios involving mutations or cellular responses to DNA damage, requiring candidates to identify the correct mechanisms or outcomes. A common pitfall is overlooking the distinction between different repair pathways and their specific roles, which can lead to incorrect answers.
One practical tip is to familiarize yourself with the clinical implications of these mechanisms, as they can inform treatment strategies for genetic disorders and cancer therapies.
Terms (37)
- 01
What is the primary function of DNA repair mechanisms?
The primary function of DNA repair mechanisms is to identify and correct damage to the DNA structure, ensuring the integrity of the genetic material and preventing mutations (Klug Cummings, Chapter on DNA Repair).
- 02
Which type of DNA damage is primarily repaired by nucleotide excision repair?
Nucleotide excision repair primarily repairs bulky DNA adducts and helix-distorting lesions, such as those caused by UV light (Klug Cummings, Chapter on DNA Repair).
- 03
How often should DNA repair mechanisms be assessed in a laboratory setting?
DNA repair mechanisms should be assessed regularly, typically during routine quality control checks, to ensure the fidelity of genetic studies (Department-style exam questions).
- 04
What is the first step in the base excision repair process?
The first step in base excision repair is the recognition and removal of the damaged base by a specific DNA glycosylase (Klug Cummings, Chapter on DNA Repair).
- 05
Under what conditions does homologous recombination primarily occur?
Homologous recombination primarily occurs during the S and G2 phases of the cell cycle, when sister chromatids are available for repair (Klug Cummings, Chapter on DNA Repair).
- 06
What is the role of DNA polymerase in DNA repair?
DNA polymerase plays a critical role in DNA repair by synthesizing new DNA strands to replace the excised or damaged sections (Klug Cummings, Chapter on DNA Repair).
- 07
Which repair mechanism is most effective for double-strand breaks?
Homologous recombination is the most effective mechanism for repairing double-strand breaks in DNA (Klug Cummings, Chapter on DNA Repair).
- 08
What type of DNA damage does mismatch repair primarily target?
Mismatch repair primarily targets base pair mismatches that occur during DNA replication (Klug Cummings, Chapter on DNA Repair).
- 09
What is the consequence of defective DNA repair mechanisms?
Defective DNA repair mechanisms can lead to increased mutation rates, genomic instability, and a higher risk of cancer (Klug Cummings, Chapter on DNA Repair).
- 10
What is the significance of the BRCA1 and BRCA2 genes in DNA repair?
BRCA1 and BRCA2 genes are crucial for homologous recombination repair of double-strand breaks; mutations in these genes are associated with increased breast and ovarian cancer risk (Klug Cummings, Chapter on DNA Repair).
- 11
How does the nucleotide excision repair mechanism initiate?
Nucleotide excision repair initiates with the recognition of DNA damage by a complex of proteins that includes XPC and XPB (Klug Cummings, Chapter on DNA Repair).
- 12
What is the role of the enzyme DNA ligase in DNA repair?
DNA ligase is responsible for sealing nicks in the DNA backbone, completing the repair process after the damaged section has been replaced (Klug Cummings, Chapter on DNA Repair).
- 13
Which DNA repair mechanism is involved in the repair of oxidative damage?
Base excision repair is primarily involved in the repair of oxidative DNA damage, such as 8-oxoguanine (Klug Cummings, Chapter on DNA Repair).
- 14
What is the function of the protein p53 in relation to DNA repair?
The protein p53 functions as a tumor suppressor that regulates the cell cycle and can induce DNA repair mechanisms or apoptosis in response to DNA damage (Klug Cummings, Chapter on DNA Repair).
- 15
What type of DNA damage does the enzyme photolyase repair?
Photolyase repairs UV-induced pyrimidine dimers through a light-dependent mechanism known as photoreactivation (Klug Cummings, Chapter on DNA Repair).
- 16
How does the cell determine which DNA repair pathway to use?
The cell determines which DNA repair pathway to use based on the type and severity of the DNA damage, as well as the phase of the cell cycle (Klug Cummings, Chapter on DNA Repair).
- 17
What is the role of the RAD51 protein in DNA repair?
RAD51 is crucial for homologous recombination, facilitating the search for homology and strand invasion during DNA repair (Klug Cummings, Chapter on DNA Repair).
- 18
What happens during the DNA damage response (DDR)?
During the DNA damage response, cells activate signaling pathways that lead to cell cycle arrest, DNA repair, or apoptosis depending on the extent of the damage (Klug Cummings, Chapter on DNA Repair).
- 19
Which DNA repair mechanism is associated with the repair of single-strand breaks?
Single-strand breaks are primarily repaired by the base excision repair mechanism (Klug Cummings, Chapter on DNA Repair).
- 20
What is the role of the enzyme AP endonuclease in DNA repair?
AP endonuclease is responsible for recognizing and cleaving the DNA backbone at apurinic/apyrimidinic sites during base excision repair (Klug Cummings, Chapter on DNA Repair).
- 21
How does the mismatch repair system recognize errors?
The mismatch repair system recognizes errors by identifying distortions in the DNA helix that occur due to mismatched base pairs (Klug Cummings, Chapter on DNA Repair).
- 22
What is the significance of the term 'excision' in DNA repair?
The term 'excision' refers to the removal of damaged or incorrect nucleotides from the DNA strand during repair processes such as nucleotide and base excision repair (Klug Cummings, Chapter on DNA Repair).
- 23
What is the outcome if DNA repair mechanisms fail to correct errors?
If DNA repair mechanisms fail to correct errors, it can lead to mutations, genomic instability, and contribute to the development of cancer (Klug Cummings, Chapter on DNA Repair).
- 24
What type of DNA damage is repaired by the SOS response in bacteria?
The SOS response in bacteria repairs extensive DNA damage, including double-strand breaks and bulky adducts, often in an error-prone manner (Klug Cummings, Chapter on DNA Repair).
- 25
What is the role of the enzyme UvrABC in nucleotide excision repair?
UvrABC is a complex of enzymes that recognizes and excises damaged DNA during nucleotide excision repair (Klug Cummings, Chapter on DNA Repair).
- 26
How does the cell cycle influence DNA repair processes?
The cell cycle influences DNA repair processes by determining the availability of sister chromatids for homologous recombination and the timing of repair mechanisms (Klug Cummings, Chapter on DNA Repair).
- 27
What is the primary mechanism for repairing DNA interstrand cross-links?
The primary mechanism for repairing DNA interstrand cross-links is the Fanconi anemia pathway, which coordinates multiple repair processes (Klug Cummings, Chapter on DNA Repair).
- 28
What is the role of the enzyme DNA polymerase beta in DNA repair?
DNA polymerase beta is involved in base excision repair, specifically in the synthesis of new DNA to fill in gaps after excision (Klug Cummings, Chapter on DNA Repair).
- 29
What is the significance of the term 'homologous' in homologous recombination?
The term 'homologous' refers to the use of a homologous template, typically a sister chromatid, to accurately repair double-strand breaks (Klug Cummings, Chapter on DNA Repair).
- 30
How does the cell respond to DNA damage during the G1 phase of the cell cycle?
During the G1 phase, the cell can activate checkpoints to halt the cell cycle and initiate DNA repair mechanisms before DNA replication occurs (Klug Cummings, Chapter on DNA Repair).
- 31
What is the function of the enzyme ligase in the context of DNA repair?
Ligase functions to seal nicks in the DNA backbone after repair processes, ensuring the continuity of the DNA strand (Klug Cummings, Chapter on DNA Repair).
- 32
What is the role of the enzyme DNA helicase in DNA repair?
DNA helicase unwinds the DNA double helix, allowing access to the damaged site for repair enzymes (Klug Cummings, Chapter on DNA Repair).
- 33
What is the consequence of mutations in DNA repair genes?
Mutations in DNA repair genes can lead to a predisposition to various cancers due to the accumulation of genetic damage (Klug Cummings, Chapter on DNA Repair).
- 34
What is the role of the Ku protein in DNA repair?
The Ku protein is involved in non-homologous end joining, recognizing and binding to double-strand breaks to facilitate their repair (Klug Cummings, Chapter on DNA Repair).
- 35
How does the DNA repair process differ between prokaryotes and eukaryotes?
The DNA repair process differs between prokaryotes and eukaryotes in complexity and the presence of multiple repair pathways in eukaryotes, while prokaryotes often rely on simpler mechanisms (Klug Cummings, Chapter on DNA Repair).
- 36
What is the significance of the term 'error-prone' in DNA repair?
The term 'error-prone' refers to repair processes that can introduce mutations, often occurring during the SOS response in bacteria (Klug Cummings, Chapter on DNA Repair).
- 37
What is the role of the enzyme RecA in bacterial DNA repair?
RecA plays a critical role in homologous recombination and the SOS response in bacteria by facilitating strand invasion and pairing (Klug Cummings, Chapter on DNA Repair).