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M2M Biochemistry and molecular biology > DNA/RNA LO > Flashcards

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

what happens at the active site of a ribosome?

location where polypeptide chain is formed