BioChem Lecture 6_DNA replication Flashcards
(14 cards)
What are the 3 main types of DNA
Satellite DNA, Single copy DNA, and Dispersed DNA
What is the function of Single copy gene DNA
this is the protein coding DNA that accounts for human genes
Describe satellite DNA
Generally not transcribed and is found in highly repetitieve clusters. A sub class trinucleotide repeates can be transcribed and causes diseases like Huntingtons
What three DNA segments are included in dispersed repetitive DNA?
long interspersed elements (LINES), short interspersed elements (SINES) and transposons
Define the function of DNA polymerase III
adds DNA nucleotides to the growing daughter strands of DNA
Define the function of Primase
synthesizes the production of an RNA primer for DNA polymerase to bind to and begin working
Define the function of Topoisomerase
removes super coils in the DNA by cleaving the DNA strands
Define the function of DNA Helicase
Unwinds short segments of the parent DNA
Define the function of DNA ligase
Catylizes the sealing in the nicks of DNA after exonuclease removes the RNA fragment and they are replaced by DNA.
Define the function of single strand binding protein
prevents the premature annealing of ssDNA back to dsDNA
Define Okazaki fragments
short segments of DNA on the lagging strand of DNA
How does polymerase function to conserve fidelity of replicated DNA?
3’ to 5’ exonucleation
What is the role of telomerase and what is special about it.
Telomerase preserves the length of telomers so they do not shorten with cell division. They are a reverse transcriptase meaning they make DNA from an RNA template.
How do DNA inhibitor medications work?
they mimick the structure of nucleosides but do not have a hydroxyl group on the 3 carbon position of the ribose. This leaves them unreactive and prevents polymerization.
