How are the DNA mutations repaired?

Answer 1

Although many cells in adult organisms are not actively dividing, they still need accurate instructions on how to function. Therefore, they need to detect and repair mutations introduced during replication or caused by environmental factors, such as mutagenic chemicals or raditaion. Most mutations are known as mismatches because they consist of base pairs that cannot form hydrogen bonds (for example, cytosine and adenine) The process by which these mutations are repaired is known as excision repair. First an enzymes recognizes the mismatch and binds to the DNA. It then breaks the sugar-phosphate bonds of the mismatched sections and removes the damage or mutant DNA. Next, DNA polymerase fills in the deleted DNA sequence. Finally another enzyme forms sugarphosphate bonds between the replacement peice and its neighboring nucleotides.

Answer 2

DNA can be damaged by various factors both intrinsic and extrinsic. DNA repair is a major defense against environmental damage to cells. This exclusive mechanism is present in almost all organisms examined including bacteria, yeast, drosophila, fish, amphibians, rodents and humans.

DNA repair process can assist the cell to avoid the risk involved in processes that minimize cell killing, mutations, replication errors, persistence of DNA damage and genomic instability to the minimum.

Persistent abnormalities in these processes may result in cancer and aging.

Using the combination of the biochemical and genetic approaches, the DNA repair mechanisms are extensively studied in E.coliwhich gives us three broad categories of
repair pathways in mammalian cells.

1. Mismatch repair of single base mispairs

A single step reaction which involves a direct reversal by a single enzyme like photolyase

b) Single and multi-step base excision mechanisms (i.e., glycosylases) and
c) Multi-step reactions involving multiple protein components.

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Answer 3

There is cellular machinery that repairs damaged DNA. If the cells weren't repaired, then they could become cancerous or dysfunctional. DNA makes proteins that repair DNA.

Answer 4

By gametogenesis and random union of gametes

Answer 5

It can cause a mutation, which in a body cell could cause a tumor to form, or if in a sex cell it can be passed on to an offspring.

Answer 6

they break apart and rebuild over time