DNA Replication
This enzyme adds newly synthesized DNA to the leading and lagging strand.
What is DNA polymerase III?
What are transversions?
These mutagens substitute for normal bases and cause tautomeric shifts. They result in transitions.
What are base analogs?
ex) 5-bromouracil
This is the first line of defense, in which DNA polymerase III removes a mismatched base with the correct base.
What is proofreading?
What are Chargraff's rules?
This enzyme links together DNA fragments synthesized via DNA polymerase I. It's primary area of activity is the lagging strand.
What is ligase?
These mutations result in frameshifts. They are usually caused by an abnormality associated with physical and chemical mutagens.
What are insertions or deletions? (indels)
This form of non-ionizing radiation can cause T-dimers to form on the DNA strand
What is UV light?
This is the 2nd level of defense, which acts by removing a strand of DNA and repairing it into a new strand. This repair mechanism uses a methylated template strand and follows DNA polymerase III closely.
What is mismatch DNA repair?
This class of nucleotides is primarily involved in dimers caused by UV radiation
This enzyme helps to prevent supercoiling of DNA that is created by the origin of replication and helicase.
This mutation is caused by damage with UV light. A result of this is deletions.
What are T-dimers?
These mutagens alter the pairing properties of bases. Examples include EMS (an alkylating agent) and nitrous acid (a deaminating agent)
This fixes uracil or modified bases in the DNA strand. It is primarily done by an endonuclease.
What is base excision repair?
Nucleotide excision fixes bulky lesions via DNA poly II
This purine is usually added at the end of an mRNA transcript as it leaves the nuclear envelope.
What is adenine?
These are short strands of nucleotides placed on both the leading and lagging strand to help DNA polymerase III get started.
What are RNA primers?
This mutation is caused by base analogs, in which a base is paired with another base that does not follow Chargraffs rules.
What are mismatches?
These chemical mutagens cause indels. They can wedge between bases in DNA and cause problems in DNA replication.
What are acridin dyes?
This repair mechanism occurs primarily in prokaryotes to fix T-dimers. Photoreactivation enzyme and blue light are activating it.
What is photoreactivation?
These occur 1 in every 100,000 base pairs. It results in adenine/cysteine going from amino to imino form and guanine/thymine going from keto to enol form.
What are tautomeric shifts?
These pieces of DNA are found on the lagging strand. A buildup of these is associated with malfunctions in DNA polymerase I.
What are Okazaki fragments?
This is the hardest mutation to repair. These are usually caused by botched repairs or extensive damage by mutagens. Cancer is primarily caused by these mutations.
What are double stranded breaks?
This physical mutagen can cause extensive damage to DNA, including substitutions, deletions, and double stranded breaks.
What are X-rays? (ionizing radiation)
What is recombinational repair?
This nucleotide is formed via deamination by nitrous acid. It is commonly found in RNA.
What is uracil?