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nucleic acids > quiz and iclicker > Flashcards

quiz and iclicker Flashcards

1
Q

hydrolysis of the nucleoside triphosphate B-Y phosphate bond provides sufficient free energy to drive the polymerisation or synthesis of DNA/RNA.

true or false?

A

false

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2
Q

A-DNA forms a left handed double helix.

true or false

A

false

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3
Q

B-DNA is stabilized by a water-spine in the minor groove.

true or false?

A

true`

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4
Q

piRNA is a functional RNA in pre-mRNA processing.

true or false

A

false

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5
Q

what amino acid change occurs in the mutation; R323Q?

A

arg at position 323 replaced by gln

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6
Q

how many carbon atoms are in isopentene?

A

5

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7
Q

how many base pairs are unwound in a standard transcription bubble?

A

14

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8
Q

SN2 nucleophilic displacement reactions require the presence of…?

A

a leaving group

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9
Q

what best describes the products of alkaline hydrolysis of RNA?

A

equimolar amounts of 2’ and 3’ nucleoside monophosphates

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10
Q

what type of enzyme is RNA polymerase?

A

DNA directed RNA polymerase

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11
Q

how many domains does the major bacterial sigma factor have?

A

4

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12
Q

what feature of the RNAP2 complex determines whether the correct NTP is in place?

A

trigger loop

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13
Q

the formation of alternative base pairs always leads to misincorporation.

true or false?

A

false

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14
Q

why does abortive initiation occur?

A

the RNA exit channel is blocked by amino acids

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15
Q

during DNA or RNA synthesis, template translocation is the final step of one round or the first of the next round.

true or false?

A

true

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16
Q

after the first 4 nucleotides hhave been incorporated into an RNA chain its composition will be;

pppNpNpNppNOH

true or false?

A

false

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17
Q

after the first 4 nucleotides hhave been incorporated into an RNA chain its composition will be;

pppNpNpNpNp

true or false?

A

false

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18
Q

polynucleotide phosphoryalse, the enzyme isolated by Marianne GM and Severo Ochoa can synthesize RNA even if just 1 NDP is provided.

true or false?

A

true

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19
Q

in the presence of 30 uM ADP and 10 uM CDP, polynucleotide phosphorylase could synthesize a polymer with the sequence;

AACCAAACACAAAAAAAACAAACA

true or false?

A

true

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20
Q

why was heparin added to the experiment at t=1 min?

A

bind any free RNAP2

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21
Q

what structural motif is commonly found in bacterial DNA-binding proteins?

A

helix-trun-helix

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22
Q

the first line shows the lac promoter sequence and the second line shows a change. will the change make it stronger or weaker?

TTTACA – 18 – TATGTT
TTTACA – 17 - TATGTT

A

stronger

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23
Q

the first line shows the lac promoter sequence and the second line shows a change. will the change make it stronger or weaker?

TTTACA – 18 – TATGTT
TTGACA – 18 – TATGTT

A

stronger

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24
Q

which RNAP is least sensitive to alpha amanitin?

A

RNAP1

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25
Q

which one of the 5 central subunits of RNAP2 is modified during promoter clearance?

A

Rpb1

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26
Q

what is the consensus sequence of the TATA box?

A

TATAWAW

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27
Q

which general transcription factor has an extended linker that blocks the RNA exit channel of RNA polymerase?

A

TFIIF

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28
Q

TFIIB contains a subunit that recognizes the TATA box.

true or false?

A

false

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29
Q

TFIIE brings RNAP2 into the pre-initiation compplex.

true or false?

A

false

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30
Q

when RNAP2 leaves the promoter, only general transcription factor TFIID is left behind.

true or false?

A

false

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31
Q

what do nuclear cell extracts contain?

A

splicing factors
DNAP
RNAP

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32
Q

in a typical electrophoretic mobility shaft assay, which component is visualized?

A

DNA fragment

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33
Q

TFIIA was originally thought to be essential for transcription by RNAP2.

true or false?

A

true

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34
Q

defects in subunits of TFIIH can lead to …?

A

trichothiodystrophy

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35
Q

what amino acid is phosphorylated by TFIIH during the process of promoter clearance in eukaryotic mRNA transcription?

A

serine

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36
Q

what enzyme is responsible for modification of yhe amino acid repeats in Rpb1 during the early stages of mRNA synthesis in eukaryotes?

A

kinase

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37
Q

what is the order in which enzymes are required for mRNA capping?

A

1 - RNAP2
2 - RNA 5’ triphosphatase
3 - guanylyl transferase
4 - guanine 7-methyl transferase

38
Q

a string of 8 uracil nucleotides is required for an effective transcription intrinsic terminator in bacteria

true or false?

39
Q

the bacterial operon contains one promoter, 2 terminators and 3 genes. if 100 units of the 1st gene are expressed, how much of the 3rd gene are expressed?

A

it depends, terminators are not 100% effective

40
Q

attenuation is a form of transcription ____

A

termination

41
Q

in some cases, transcription termination in bacteria requires the action if the ___ protein.

42
Q

what is cDNA?

A

complementary DNA

43
Q

which of the following enzymes are used in preparing cDNA?

A

reverse transcriptase

44
Q

which one of the following snRNPs recognizes the 5’ splice junction sequence?

45
Q

which one of the following pairs is critical to the spliceosome’s catalytic activity?

46
Q

what is the conserved sequence elements in the major class of spliceosomal introns?

A

GU ——- A —–Y15 —— AG

47
Q

what is the leaving group during the first step of group 1 self splicing?

48
Q

what is the leaving group during the first step of spliceosomal splicing

A

exon 1 (upstream)

49
Q

what is the conserved sequence found at the 5’ end of a spliceosomal intron/

50
Q

how is apoB48 generated in intestinal cells?

A

deamination of cytosine base

51
Q

what enzyme interacts with deamination of cytidine?

A

APOBEC enzyme

52
Q

what enzyme interacts with guanosine?

A

class 1 intron

53
Q

what enzyme interacts with 5’-5’ triphosphate ?

A

guanylyl transferase

54
Q

what enzyme interacts with the repeated addition of 3’ nucleotides?

A

poly(A) polymerase

55
Q

waht enzyme interacts with U2-U6?

A

nucleophilic adenosine

56
Q

the eukaryotic ribosome consists of a 30S small unti and a 50S large unit.

true or false?

57
Q

which aare found in bacterial and eukaryotic ribosomes?

28S
23S
18S
5.8S
16S

A

eukaryotic
bacterial
eukaryotic
eukaryotic
bacterial

58
Q

which part of the tRNA loop plays a role in proper alignement of the codon?

A

hypermodified purine on the 3’ end close to anticodon

59
Q

whydo aminoscyl-tRNA synthetases need ATP?

A

to add the 3’A onto the tRNA (leaving group)

60
Q

large non-cognate amino acids are kept out of the aminoacylation site of an aaRS by the property of;

A

size exclusion

61
Q

transamidases convert Glu-tRNA^Glu to Gln-tRNA^Glu.

true or false

62
Q

transformylase must distinguish between tRNA^fmet and tRNA^met.

true or false?

63
Q

isoleucine cannot be added to tRNA by ValRS.

true or false?

64
Q

valien cannot be added to tRNA by IleRS.

true or false?

65
Q

val is removed from tRNA by proof-reading site of IleRS.

true or false?

66
Q

Ile is removed from tRNA by the proof-reading site of ValRS

true or false?

A

false - wont even be added

67
Q

what identity element is used by AlaRS for tRNA^ala?

68
Q

what delivers actiavted tRNAs to the ribosome?

A

eEF1A and EFTu

69
Q

eRF3 escorts eRF1 to the ribosome during the termination phase of translation. Which bacterial translation factor does eRF3 functionally resemble?

70
Q

Which translation factor recognizes the stop codon?

71
Q

All Class I Release Factors in bacteria and eukaryotes have the same tripeptide sequence that is needed for hydrolysis of the synthesized protein from the final tRNA. What is that tripeptide?

72
Q

What is a GAP protein?

A

One that activates the GTPase activity of another

73
Q

Name a translation factor that acts as a GAP protein

74
Q

Name a translation factor that acts as a GTPase

75
Q

Match the translation initiation factor to its stage in initiation

Prepare the mRNA for translation

Assist binding of the large subunit

Scan mRNA for the start codon

Prepare the small subunit for translation

A

eIF4G
eIF5B
eIF4A
eIF1

76
Q

Met-tRNAiMet is brought to the P site by eIF2

true or false

77
Q

fMet-tRNAiMet is brought to the P site by IF2

true or false

A

false - bacteria

78
Q

what best resembles a Shine-Dalgarno sequence?

79
Q

To what RNA is the Shine-Dalgarno sequence complementary?

80
Q

What does the Kozak sequence interact with?

81
Q

What term describes the circumstance when a stop codon is misread by a tRNA with a mutated anticodon?

A

nonsense suppression

82
Q

Which one of the following anticodon mutations would allow its tRNA to recognise a stop codon?

5’-GUA-3’ –> 5’-CUA-3’

5’-UUA-3’ –> 5’-GUA-3’

5’-CUA-3’ –> 5’-CAA-3’

5’-UAA-3’ –> 5’-UAG-3’

83
Q

Which virus used programmed stop codon readthrough to regulate synthesis of its GagPol polyprotein?

A

Murine Leukemia Virus

84
Q

Other than RSV and MuLV, what is another well-studied virus that expresses a GagPol polyprotein?

85
Q

What is unique about the amino acids selenocysteine and pyrrolysine?

A

Stop codons are used to direct their incorporation into proteins

86
Q

Which of the following statements is true?

A regular tRNALys is charged with pyrrolysine by PylRS

A special tRNAPyl is charged with Pyrrolysine by PylRS

A special tRNALys is charged with Lysine by PylRS

A special tRNAPyl is charged with Pyrrolysine by LysRS

87
Q

Which term has been used to describe the pyrrolysine tRNA synthesise-tRNA pair?

A

promiscuous

88
Q

Which enzyme is required to convert Serine to Selenocysteine?

A

Selenocysteine synthase

89
Q

How many stop codons are recognised by RF2?

90
Q

Which of the following proteins stimulates eRF1-mediated peptide hydrolysis?

91
Q

In bacteria, the special RNA that participates in solving the problem of stalled ribosomes has properties of which one of the following?

nucleic acids (21 decks)

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