Table of Contents
What type of radiation causes double-stranded breaks?
ionizing radiation
All organisms suffer double-strand breaks (DSBs) in their DNA as a result of exposure to ionizing radiation.
What are double-strand breaks DNA?
Double-strand breaks in DNA can be lethal to a cell. By-products of the cell’s own metabolism such as reactive oxygen species can damage DNA bases and cause lesions that can block progression of replication. The result is double-strand breaks (DSBs) in the chromosome.
How does radiation cause damage?
Ionizing radiation can affect the atoms in living things, so it poses a health risk by damaging tissue and DNA in genes. has sufficient energy to affect the atoms in living cells and thereby damage their genetic material (DNA). Fortunately, the cells in our bodies are extremely efficient at repairing this damage.
What causes double strand break repair?
Within the cell, reactive oxygen species generated by normal respiratory metabolism can cause double-strand breaks, as can stalled DNA replication. External agents that cause double-strand breaks include ionizing radiation and certain chemotherapeutic drugs.
How does radiation cause double strand breaks?
DNA double strand breaks (DSBs) are considered the most lethal form of DNA damage. IR damages DNA by direct deposition of energy and also indirectly, by ionization of water molecules to produce hydroxyl radicals that attack the DNA.
How are double stranded DNA breaks repaired?
DNA double-strand breaks are repaired by means of two main mechanisms: nonhomologous end joining and homologous recombination (see Figure 1). Homologous recombination is the preferred route in yeast. It involves invasion of the broken DNA strands into a homologous DNA duplex molecule.
How can DNA repair mechanisms be improved?
Higher intensity activities in particular (running, swimming, fast cycling) appeared to be associated with the greatest benefit to DNA repair capacity. Biologically, physical activity may increase DNA repair by inducing expression of enzymes which dispose of harmful oxygen radicals and repair DNA damage .
How does radiation cause mutation in DNA?
High levels of ionizing radiation can result in double-strand DNA breaks. Ultraviolet (UV) radiation from the sun results in dimerization of thymidine residues in DNA, and defective repair of these dimers leads to mutation.