Flashcards in DNA/RNA LO Deck (64)
what compound can increase the speed of deamination and where is it mostly found?
nitrous acid, cigarette smoke
what becomes sensitive to breakage after depurination?
what happens during depurination?
breaking off purine base from ribose and leaving a hydroxyl group
what can happen if you have a few depurinations right next to each other on DNA?
breakage of the phosphate backbone
what is usually created as a result of UV radiation in DNA?
how are thymine dimers usually repaired?
nucleotide excision repair
what type of agents are considered carcinogens?
alkylating agents (mustard gas, dimethylsulfate, dimethylnitrosamine, CISPLATIN (cancer drug))
through what process does actinomycin D work?
intercalation. Molecule intercalates into the DNA and then replication cannot continue
why can intercalation cause cancer cells to enter apoptosis?
causes kink in DNA and replication cannot occur, therefore cell recognizes that it is not functioning properly
what does topoisomerase do?
removes knots of DNA by removing supercoils
what is underwound DNA?
produces negative supercoils and decreased twist
what is overwound DNA?
produces positive supercoils and increased twist
what are the 4 methods of attacking DNA metabolism?
1. syntehsis of precursors (dNTP)
2. intercalation (getting in the middle)
3. covalently binding bps
4. disrupting topoisomerases
what are the 3 main types of RNA in a human cell?
what is the function of rRNA?
(ribosomal RNA) make up functional units of ribosomes and translate mRNA
what is the function of tRNA?
(transfer RNA) brings amino acid specified by codon to ribosome
what is the function of snRNA and siRNA?
(small nuclear RNA and small interfering RNA) function with in-cell modifications such as splicing
what is the function of miRNA and siRNA?
(micro RNA and small interfering RNA) downregulate gene expression
which is more easily hydrolyzed when comparing RNA and DNA?
why is RNA more easily hydrolyzed than DNA?
there can be a nucleophilic attack by 2' OH on the phosphodiester bond
what is the ease of hydrolyzing RNA important for?
changes in gene expression
what is the usually the final form of RNA in humans after it is produced?
single strand RNA
why can RNA produce many different conformations?
there is rotation around the bonds, not hindered by hydrogen bonds from another strand like in DNA
How does puromycin work?
nucleotide analogue that mimics tRNA acceptor region. therefore allows peptide transfer and termination of translation
where do most bacteria get their antibiotic resistance from?
environmental DNA such as plasmids
how does RNA form hairpin loops?
AU, GC, and GU base pairs
what does E site of ribosomes hold?
holds RNA that will exit
what does the P site of ribosomes hold?
holds tRNA with growing polypeptide attached
what does the A site of ribosomes hold?
holds the aminoacyl tRNA