Molecular Motors- Helicases

Beschreibung

Structural Basis for Biological Function (Molecular Motors) Quiz am Molecular Motors- Helicases, erstellt von gina_evans0312 am 15/12/2013.
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Quiz von gina_evans0312, aktualisiert more than 1 year ago
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Erstellt von gina_evans0312 vor fast 11 Jahre
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Zusammenfassung der Ressource

Frage 1

Frage
DNA helicase unwinds DNA into ssDNA for what processes?
Antworten
  • DNA repair
  • DNA replication
  • DNA recombination
  • DNA destruction

Frage 2

Frage
DNA helicase's process and translocate branched structures
Antworten
  • True
  • False

Frage 3

Frage
Name (a) branched DNA structure(s)
Antworten
  • Holliday junctions
  • D loops
  • Binary helix
  • T loops

Frage 4

Frage
RNA helicases cannot destabilize RNA secondary structures
Antworten
  • True
  • False

Frage 5

Frage
RNA helicases help in which of the following processes A- Promote ribosome assembly B- RNA translocation C-RNA splicing D- RNA editing and transport E-RNA degredation
Antworten
  • A, C & D
  • B, C & E
  • A only
  • E only
  • All of them

Frage 6

Frage
Some helicases can work on both RNA & DNA
Antworten
  • True
  • False

Frage 7

Frage
Which of the following unwind RNA-DNA hybrids
Antworten
  • RNA helicase, then DNA helicase
  • DNA helicase, then RNA helicase
  • RNA/DNA helicases

Frage 8

Frage
RNA/DNA helicases perform which of the following functions?
Antworten
  • Transcription termination
  • Regulation of DNA replication initiation
  • RNA degredation

Frage 9

Frage
All helicases use energy from NTP hydrolysis to translocate along polynucleotides
Antworten
  • True
  • False

Frage 10

Frage
Helicases are dependent on Fe2+
Antworten
  • True
  • False

Frage 11

Frage
Helicases can take which of the following forms (commonly)
Antworten
  • Hexamers
  • Monomers
  • Trimers
  • Dimers
  • Tetramers
  • Pentamers

Frage 12

Frage
Helicases can have an oligomeric structure
Antworten
  • True
  • False

Frage 13

Frage
Helicases can be
Antworten
  • Unidirectional
  • Bidirectional
  • Both
  • Bidirectional or unidirectional

Frage 14

Frage
What is the difference between translocases and helicases?
Antworten
  • Translocases -transcribe and separate DNA strands Helicases- transcribed DNA strands only
  • Helicases-transcribe and separate DNA strands Translocases- transcribed DNA strands only

Frage 15

Frage
Give an example of a DNA/RNA unwinding helicase/translocase
Antworten
  • PCRA
  • Type 1 restriction enzymes
  • Ruv B/Reg G
  • Mfd

Frage 16

Frage
Name a helicase/translocase that effects protein motion on DNA
Antworten
  • PCRA
  • Type 1 Restriction Enzyme
  • Ruv B/ Reg G
  • Mfd

Frage 17

Frage
Name a necleoprotein complex remodelling helicase
Antworten
  • Mfd
  • Ruv B/Reg G
  • PCRA
  • Type 1 Restriction Enzymes

Frage 18

Frage
Name a DNA/RNA remodelling helicase
Antworten
  • Ruv B/ Reg G
  • PCRA
  • Type 1 Restriction Enzymes
  • Mfd

Frage 19

Frage
Helicases are divided into seven superfamilies based on primary structure, and then 3 structural classes
Antworten
  • True
  • False

Frage 20

Frage
The two structural classes are monomers and dimers
Antworten
  • True
  • False

Frage 21

Frage
All helicases contain a Rec B fold
Antworten
  • True
  • False

Frage 22

Frage
EVERY helicase molecule contains which of the following?
Antworten
  • An ATP binding site
  • An NTP binding site
  • A separate polynucleotide binding site
  • A GTP binding site
  • A linked polynucleotide binding site

Frage 23

Frage
The _TP binding site and the nucleotide binding site on a helicase are allosterically linked
Antworten
  • True
  • False

Frage 24

Frage
Type A helicases (like PCRA) travel in which direction?
Antworten
  • 3' > 5'
  • 5' > 3'
  • Both ways

Frage 25

Frage
Rec D is a Type 2 helicase- in which direction does it travel?
Antworten
  • 5' > 3'
  • Both ways
  • 3' . 5'

Frage 26

Frage
Rec BCD is a bipolar helicase
Antworten
  • True
  • False

Frage 27

Frage
In a bacterial Holliday Junction with a stalled replication fork, what is required to allow replication to continue?
Antworten
  • RuvB
  • ATP
  • PRCA
  • GTP

Frage 28

Frage
If Holliday Junctions cannot be repaired, they lead to a cruciform structure
Antworten
  • True
  • False

Frage 29

Frage
What is the slowest rate of movement of a helicase?
Antworten
  • 10 bp/sec
  • 8 bp/sec
  • 12 bp/sec

Frage 30

Frage
Rate of helicase movement is dramatically dependent on protein partners
Antworten
  • True
  • False

Frage 31

Frage
The fastest known helicase moves around 4000 bp/sec
Antworten
  • True
  • False

Frage 32

Frage
Define Helicase Processivity
Antworten
  • How fast it moves along the DNA/RNA
  • How far it can move before it falls off
  • How far it moves per substrate hydrolysis

Frage 33

Frage
Helicases can move around 10-30,000 base pairs before falling off depending on the helicase (and it's protein partners)
Antworten
  • True
  • False

Frage 34

Frage
Step size is a theoretical limit due to the entropy of NTP hydrolysis
Antworten
  • True
  • False

Frage 35

Frage
Step size is the theoretical avg no of bp unwound per NTP hydrolysis cycle
Antworten
  • True
  • False

Frage 36

Frage
The limit on step size = Energy required to melt the bp x step size
Antworten
  • True
  • False

Frage 37

Frage
What is the experimental limit of step size?
Antworten
  • 0.3-3 bp
  • 0.5- 5bp
  • 0.7- 7 bp

Frage 38

Frage
What is this image showing?
Antworten
  • The 'Inchworm' helicase movement model
  • The 'active rolling model'

Frage 39

Frage
Which of the following is believed to be the unwinding mechanism used by helicases?
Antworten
  • Passive- DNA is frayed by heat and the translocation occurs in the presence of ATP
  • Active- ATP activates molecules that bind to and actively distort DNA before ATP dependent translocation can occur

Frage 40

Frage
PCRA is made of how many domains?
Antworten
  • 4 - 1A/B & 2A/B
  • 2 - 1A & 2A
  • 6 1A/B, 2A/B & 3A/B

Frage 41

Frage
PCRA activity is dependent on its protein partners
Antworten
  • True
  • False

Frage 42

Frage
PCRA is an ATPase with...
Antworten
  • A 3' > 5' polarity
  • A 5' > 3' polarity
  • A low rate of 30 bp/sec
  • A high rate of 300 bp/sec
  • A low processivity of 10 bp/sec
  • A high processivity of 100 bp/sec
  • A step size of 16 bp/ATP
  • A step size of 6 bp/ATP

Frage 43

Frage
The conserved Helicase motifs of PCRA are in the accessory domains
Antworten
  • True
  • False

Frage 44

Frage
Aromatic stacking occurs between the inserted aa and bp
Antworten
  • True
  • False

Frage 45

Frage
Which of the following will bind to the DNA
Antworten
  • Tryptophan
  • Phenylalanine
  • Tyrosine
  • Histidine

Frage 46

Frage
The complex of PCRA-DNA remains the same during ATP binding and ATP hydrolysis
Antworten
  • True
  • False

Frage 47

Frage
Duplex distortion in the PCRA substrate complex suggests a Passive unwinding system
Antworten
  • True
  • False

Frage 48

Frage
Partner proteins are required by PCRA for which processes?
Antworten
  • Loading
  • Unwinding
  • Activation
  • Catalytic modification

Frage 49

Frage
Hexameric helicases can be part of the replisome
Antworten
  • True
  • False

Frage 50

Frage
Hexameric helicases have a toroidal strcture to confer high processivity
Antworten
  • True
  • False

Frage 51

Frage
ATP binds where on hexameric helicases?
Antworten
  • To the pockets present in each monomer
  • To the pocket made by the interaction of all 6 monomers

Frage 52

Frage
ssDNA is bound in the central channel to a 'spiral staircase' of bining loops
Antworten
  • True
  • False

Frage 53

Frage
ATP binding pocket changes _ around the ring
Antworten
  • Sequentially- one at a time
  • At the same time
  • Sequentially- two at a time

Frage 54

Frage
ATP binding correlates with loop hight in the central channel
Antworten
  • True
  • False
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