Molecular Biology: DNA Repair Mechanisms

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What are the main causes of DNA breaks?

Ionizing radiation, thermal disruption, industrial chemicals, and environmental chemicals

What is the role of DNA repair molecules in the repair process?

They bind at or near the damage site and induce a cascade of reactions to allow DNA repair to take place

What type of DNA damage is caused by chemicals or radiation?

Single strand breaks

What is the main function of base excision repair?

To repair damage caused by oxidation, alkylation, hydrolysis, or deamination Signup and view all the answers

What are the key enzymes involved in base excision repair?

DNA glycosylase, DNA polymerase, and DNA ligase Signup and view all the answers

When does base excision repair take place?

All the time Signup and view all the answers

What is the characteristic of Bloom's syndrome?

Sunlight hypersensitivity and high incidence of malignancies, such as leukemia Signup and view all the answers

What is the association between inherited mutations in DNA repair genes and cancer?

Strongly associated with high cancer risks Signup and view all the answers

What is the role of BRACA1 and BRACA2 in relation to cancer?

Associated with breast cancer and multiple DNA repair pathways Signup and view all the answers

How do cancer therapies, such as chemo- and radio-therapy, work?

By overwhelming the cell's capacity to repair DNA damage, leading to cell death Signup and view all the answers

What is the goal of modern cancer treatments?

To localize DNA damage to cancer cells and tissues using physical or biochemical means Signup and view all the answers

What is the balance that cancer cells must maintain?

The balance between DNA repair and DNA damage Signup and view all the answers

What type of repair occurs immediately after DNA replication and involves the removal of an extensive region up to the next GATC-sequence in the new strand?

MIS-MATCH REPAIR Signup and view all the answers

What is the primary mechanism of repair for double strand breaks, but is prone to error and mutagenesis?

NON-HOMOLOGOUS END JOINING REPAIR Signup and view all the answers

What type of repair uses enzymes that normally perform genetic recombination between homologous chromosomes during meiosis?

HOMOLOGOUS RECOMBINATION REPAIR Signup and view all the answers

What is the result of errors in the NON-HOMOLOGOUS END JOINING REPAIR system?

Development of cancer and immunodeficiency syndromes Signup and view all the answers

What is the primary cause of double strand breaks in DNA?

High energy radiation or oxidative free radicals Signup and view all the answers

What is the function of GATC-endonuclease in MIS-MATCH REPAIR?

Removal of an extensive region up to the next GATC-sequence in the new strand Signup and view all the answers