DNA can get damaged because of things around us or from inside our bodies. When this happens, it can lead to changes called mutations. Our cells have special ways to fix this damage, which is really important to keep our DNA healthy. Here are the main ways our cells repair DNA:

1. Direct Repair:

   • In this method, the cell directly fixes the damage. For example, an enzyme (a type of helper protein) called photolyase can fix damage from UV light by reversing the changes it caused.

2. Base Excision Repair (BER):

   • This method fixes small issues in the DNA. Around 500 to 1,000 parts of DNA can get damaged in each cell every day. BER works like this:
     • First, a special enzyme called DNA glycosylase finds and removes the damaged part.
     • Then, another enzyme called AP endonuclease cuts the DNA strand to help remove the bad section.
     • After that, DNA polymerase helps to fill in the gap, and finally, DNA ligase seals everything up.

3. Nucleotide Excision Repair (NER):

   • NER is used to repair larger problems in DNA that change its shape. This method can fix thousands of spots every day. Here’s how it works:
     • First, the cell detects where the damage is.
     • Next, a small piece of the damaged DNA is cut out.
     • Finally, DNA polymerase fills in this piece again and DNA ligase seals it up.

4. Mismatch Repair (MMR):

   • MMR fixes mistakes that happen when DNA is copied. For example, sometimes the wrong base pairs get matched up. This system can fix 99% of these mistakes after the DNA is copied, which helps lower the chances of mutations.

5. Homologous Recombination (HR) and Non-Homologous End Joining (NHEJ):

   • These two processes help repair serious breaks in the DNA strand. HR is used when the cell is preparing to divide and is very careful in its repairs. NHEJ can fix these breaks at any time but may make more mistakes in the process.

In summary, these DNA repair methods are really important. They help our cells survive and reduce the chance of diseases, like cancer.