Flashcards in Kandpal- Replication and Telomeres Deck (44):
what is the difference in number of replication origins between bacteria and mamallian cells?
bacteria have a single origin of replication and mammalian cells have multiple origins of replication
which ploymerase is has primase activity?
which polymerase has repair activity?
which polymerase is used for mitochondrial replication?
which polymersae is needed for nuclear replication?
delta polymerase and gamma polymerase
are okazaki fragments bigger in mammalian cells than they are in bacteria cells?
no. they are smaller (0.1-0.2 Kb) and bacteria are bigger (1.0-2.0 Kb)
what is RNaseH needed for?
to degrade the RNA part of the RNA-DNA hybrid
what is the shape of a bacteria (e.Coli) genome and the shape of a mammalian genome?
bacteria is circular and mammalian is linear
at the end of replication, what happens after the RNA primer is removed from the 5' end?
it is not filled up, because there is no polymerase availabe with 3'--> 5' activity
what eventually happens to the 5' end?
they will continue to shorten after each replication cycle which can lead to consequences like eventual coding loss
what do chromosome replication and stable propagation require?
origins of replication
what helps to attach chromosomes to the nuclear envelope?
why is it important that telomeres help to seal the ends of chromosomes?
to avoid undesirable fusion an avoid aberrant recombination
what kind of repeats do telomeres have and how are they synthesized?
hexameric repeats that are synthesized by telomerase
what makes up a telomerase?
what subunit of telomerase is responsible for reverse transcriptase activity?
which subunit of the telomerase helps to serve as a template?
RNA (150 nucleotide long)
what does C-A strand degradation in telomeres lead too?
generation of G-tail
what is the proposed model that describes how telomeres protect chromosome ends?
G-quadruplex or G-Quartet Structure.
4 G bases on the same strand stack-up by base pairing
what type of cells in humans are known to have telomerase activity?
germ cells, isolated fibroblasts (mainly in elderly individuals)
telomeres are referred to as the mitotic clock. why?
because the shorter they become in length, the more likely replicative senescense or apoptosis will occur
how does telomerase activity relate to human cancer?
normal tissues will not have telomerase (except germ cell) but tumors have telomerase activity
what would a scientist target in order to intervene in antitumor activity?
telomerase activity and telomere structure
what is the function of the telomerase inhibitor GRN163L (oligonucleotide)?
it is a competitive inhibitor that binds to the active site of the enzyme (13-mer oligonucleotide)
what are the effects of the G-qudruplex stabilizing agent RHPS4 (G-quadruplex ligand)?
stabilizes G-quadruplex and prevents attachment of telomerase.
what is pentacylic acridinium methosulfate?
RHPS4 (G-quadruplex ligand)
what is considered to be an obligatory intracellular parasite?
virus (completely dependent on host)
what is the name for an inert virus and what is the outer protective layer called?
virion. the nucleic acid is wrapped in a capsid
can viruses have envelopes?
technically yes, if they acquire them from the host cell membrane
is virus DNA single or double stranded?
is virus RNA single of double stranded?
how are viral nucleic acids replicated?
only replicated in host cells using host cell machinery
how does a viral genome replicate?
requires reverse transcriptase so that RNA can be converted to DNA for replication
why do viruses require integrase enzyme?
in order for cDNA to be integrated into the host genome
how does reverse transcription work during HIV replication?
utilizes lysyl tRNA as a template
what would be a target to inhibit HIV replication?
replication integrase protease
what is targeted to prevent HIV infection?
fusion, reverse transcriptase, pretease and integrase
what is a common nucleotide analogue drug that is used for treatment of HIV?
zidovudine (ZDV, AZT) which is an analouge of deoxythymidine
how does zidovudine work?
prevents DNA chain elongation by reverse transcriptase (absence of 3' OH)
antibiotics use inhibitors of what enzyme to prevent DNA replication?
inhibitors of bacterial gyrase
chemotherapy uses inhibitors of what enzyme to prevent DNA replication?
inhibitor of human topoisomerases
what 4 things would you want to inhibit the synthesis of in order to limit the supply of substrates?
dATP, dCTP, dGTP, dTTP
what is the role of 5-Fluorouracil in cancer chemotherapy?
inhibits DNA synthesis by inhibiting thymidylate synthase (an enzyme for TMP synthesis)