Flashcards in DNA/RNA LO Deck (64)
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31
what compound can increase the speed of deamination and where is it mostly found?
nitrous acid, cigarette smoke
32
what becomes sensitive to breakage after depurination?
phosphate backbone
33
what happens during depurination?
breaking off purine base from ribose and leaving a hydroxyl group
34
what can happen if you have a few depurinations right next to each other on DNA?
breakage of the phosphate backbone
35
what is usually created as a result of UV radiation in DNA?
thymine dimers
36
how are thymine dimers usually repaired?
nucleotide excision repair
37
what type of agents are considered carcinogens?
alkylating agents (mustard gas, dimethylsulfate, dimethylnitrosamine, CISPLATIN (cancer drug))
38
through what process does actinomycin D work?
intercalation. Molecule intercalates into the DNA and then replication cannot continue
39
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
40
what does topoisomerase do?
removes knots of DNA by removing supercoils
41
what is underwound DNA?
produces negative supercoils and decreased twist
42
what is overwound DNA?
produces positive supercoils and increased twist
43
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
44
what are the 3 main types of RNA in a human cell?
1. structural
2. regulatory
3. information-containing
45
what is the function of rRNA?
(ribosomal RNA) make up functional units of ribosomes and translate mRNA
46
what is the function of tRNA?
(transfer RNA) brings amino acid specified by codon to ribosome
47
what is the function of snRNA and siRNA?
(small nuclear RNA and small interfering RNA) function with in-cell modifications such as splicing
48
what is the function of miRNA and siRNA?
(micro RNA and small interfering RNA) downregulate gene expression
49
which is more easily hydrolyzed when comparing RNA and DNA?
RNA
50
why is RNA more easily hydrolyzed than DNA?
there can be a nucleophilic attack by 2' OH on the phosphodiester bond
51
what is the ease of hydrolyzing RNA important for?
changes in gene expression
52
what is the usually the final form of RNA in humans after it is produced?
single strand RNA
53
why can RNA produce many different conformations?
there is rotation around the bonds, not hindered by hydrogen bonds from another strand like in DNA
54
How does puromycin work?
nucleotide analogue that mimics tRNA acceptor region. therefore allows peptide transfer and termination of translation
55
where do most bacteria get their antibiotic resistance from?
environmental DNA such as plasmids
56
how does RNA form hairpin loops?
AU, GC, and GU base pairs
57
what does E site of ribosomes hold?
holds RNA that will exit
58
what does the P site of ribosomes hold?
holds tRNA with growing polypeptide attached
59
what does the A site of ribosomes hold?
holds the aminoacyl tRNA
60
