What is DNA repair?
What are the mechanisms of DNA repair?
What is DNA stability?
DNA is the genetic information in each living cell. It is responsible for how we look and is essential to life itself. Our DNA is always under attack by environmental factors, which lead to DNA damage. (1) If the DNA damage is not fixed, it could lead to mutation and disease. One example of the DNA damage is skin cancer caused by excessive exposure to UV sunlight radiation. (1) Another example of DNA damage is tobacco toxicity in which the tobacco toxicant can lead to mutations in the lung cells. (1) Such mutations in the lung cells can cause lung cancer. Other toxicant agents that can lead to DNA damage are oxidative free radicals. (1)© BrainMass Inc. brainmass.com October 25, 2018, 8:43 am ad1c9bdddf
There are other natural genetic processes that may cause DNA damage or DNA error. (1) DNA replication, the process by which nucleotide bases are added to the growing chain of DNA, is a major factor in determining spontaneous mutation. (1) DNA polymerase, an enzyme that adds nucleotide to the growing DNA strand, can make mistake by adding the incorrect nucleotide bases. (1) There are proofreading enzymes that recognize and correct these incorrect insertions. (1) However, other mutations cannot escape the mutation and these can cause DNA damage.
DNA repair mechanisms involved the detection and repair of various type of DNA damage caused by either environmental factors or by replication errors. (1) The integrity and stability of DNA are dependent on the mechanism of DNA repair. DNA repair is crucial to the regulation of the cell cycle. (1) During the cell cycle, DNA replication occurred in the S phase and stop if there are DNA damages. (1) The cell has developed certain checkpoint mechanisms to ensure that DNA is intact before permitting DNA replication. (1) These DNA damage checkpoint mechanisms ...
DNA repair mechanisms are essential for the survival of the cells. All cells have DNA repair mechanisms to repair damages in the DNA caused by UV sunlights, chemical toxicants, and environmental toxicants. DNA repair functions to correct the errors cause by DNA polymerase in replicating a new DNA strand. DNA repair process acts like a proofreading machine in correcting and replacing incorrect bases. There are several DNA repair mechanisms: nonhomologous recombination, homologous recombination, base excision repair, post-replicative repair, and many others not yet mentioned. In the absence of DNA repair, there would be diseases that will develop. It is essential that we elucidate the basic mechanisms in DNA repair.
DNA Repair, Cancer, Retrovirus, & Transposons
a.Describe in detail how a direct DNA repair mechanism works.
b.Can you think of a way in which you could inhibit this repair mechanism in bacteria that have been exposed to UV radiation?
For each of the following, give a brief description:
d.post replication repair
a.What is cancer? Include in your answer a description of oncogenes.
b.Explain how a mutated DNA repair gene could lead to a cancer.
c.If a mutation occurs in a gene in a skin cell, describe two possible outcomes for the future of that cell.
a.What is a retrovirus?
b.How can a retrovirus cause the transformation of a normal cell into a cancer cell?
c.What is a transforming retrovirus and how does it cause cancer?
a.What is a transposon? In you answer include two distinguishing features of a transposon.
b.What is meant by conservative and replicate transfer?
c.Briefly describe the mechanism of action of the Ds and Ac transposons as discovered in maize by McClintock.