At what stage of the cell cycle does DNA proofreading occur?
The S phase stands for synthesis and is when DNA is replicated. The G2 phase stands for gap 2 and is when DNA is proofread and DNA damage is repaired. The M phase is mitosis, which is further broken down into prophase, metaphase, anaphase, telophase, and cytokinesis. Prophase is when the chromosomes condense.
What is the process of proofreading by DNA polymerase?
DNA polymerases are the enzymes that build DNA in cells. During DNA replication (copying), most DNA polymerases can “check their work” with each base that they add. This process is called proofreading. Polymerase uses 3′ to 5′ exonuclease activity to remove the incorrect T from the 3′ end of the new strand.
Why is there no primer in transcription?
RNA primers are needed to begin replication because DNA polymerase is unable to do it alone. DNA transcription does not have the same problem because RNA polymerase is capable of initiating RNA synthesis.
Why is RNA primer not a DNA primer?
Definition. Primer RNA is RNA that initiates DNA synthesis. Primers are required for DNA synthesis because no known DNA polymerase is able to initiate polynucleotide synthesis. Primases are special RNA polymerases that synthesize short-lived oligonucleotides used only during DNA replication.
Can mutated genes be corrected?
Making such double-stranded breaks in DNA can result in unwanted genetic material being inserted or deleted, which can have consequences including activating genes that cause cancer. Most mutations cannot be corrected easily without creating these undesirable genetic by-products.