Molecular Motors- Helicases

Descripción

(Molecular Motors) Structural Basis for Biological Function Test sobre Molecular Motors- Helicases, creado por gina_evans0312 el 15/12/2013.
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Test por gina_evans0312, actualizado hace más de 1 año
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3

Resumen del Recurso

Pregunta 1

Pregunta
DNA helicase unwinds DNA into ssDNA for what processes?
Respuesta
  • DNA repair
  • DNA replication
  • DNA recombination
  • DNA destruction

Pregunta 2

Pregunta
DNA helicase's process and translocate branched structures
Respuesta
  • True
  • False

Pregunta 3

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

Pregunta 4

Pregunta
RNA helicases cannot destabilize RNA secondary structures
Respuesta
  • True
  • False

Pregunta 5

Pregunta
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
Respuesta
  • A, C & D
  • B, C & E
  • A only
  • E only
  • All of them

Pregunta 6

Pregunta
Some helicases can work on both RNA & DNA
Respuesta
  • True
  • False

Pregunta 7

Pregunta
Which of the following unwind RNA-DNA hybrids
Respuesta
  • RNA helicase, then DNA helicase
  • DNA helicase, then RNA helicase
  • RNA/DNA helicases

Pregunta 8

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

Pregunta 9

Pregunta
All helicases use energy from NTP hydrolysis to translocate along polynucleotides
Respuesta
  • True
  • False

Pregunta 10

Pregunta
Helicases are dependent on Fe2+
Respuesta
  • True
  • False

Pregunta 11

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

Pregunta 12

Pregunta
Helicases can have an oligomeric structure
Respuesta
  • True
  • False

Pregunta 13

Pregunta
Helicases can be
Respuesta
  • Unidirectional
  • Bidirectional
  • Both
  • Bidirectional or unidirectional

Pregunta 14

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

Pregunta 15

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

Pregunta 16

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

Pregunta 17

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

Pregunta 18

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

Pregunta 19

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

Pregunta 20

Pregunta
The two structural classes are monomers and dimers
Respuesta
  • True
  • False

Pregunta 21

Pregunta
All helicases contain a Rec B fold
Respuesta
  • True
  • False

Pregunta 22

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

Pregunta 23

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

Pregunta 24

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

Pregunta 25

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

Pregunta 26

Pregunta
Rec BCD is a bipolar helicase
Respuesta
  • True
  • False

Pregunta 27

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

Pregunta 28

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

Pregunta 29

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

Pregunta 30

Pregunta
Rate of helicase movement is dramatically dependent on protein partners
Respuesta
  • True
  • False

Pregunta 31

Pregunta
The fastest known helicase moves around 4000 bp/sec
Respuesta
  • True
  • False

Pregunta 32

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

Pregunta 33

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

Pregunta 34

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

Pregunta 35

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

Pregunta 36

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

Pregunta 37

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

Pregunta 38

Pregunta
What is this image showing?
Respuesta
  • The 'Inchworm' helicase movement model
  • The 'active rolling model'

Pregunta 39

Pregunta
Which of the following is believed to be the unwinding mechanism used by helicases?
Respuesta
  • 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

Pregunta 40

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

Pregunta 41

Pregunta
PCRA activity is dependent on its protein partners
Respuesta
  • True
  • False

Pregunta 42

Pregunta
PCRA is an ATPase with...
Respuesta
  • 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

Pregunta 43

Pregunta
The conserved Helicase motifs of PCRA are in the accessory domains
Respuesta
  • True
  • False

Pregunta 44

Pregunta
Aromatic stacking occurs between the inserted aa and bp
Respuesta
  • True
  • False

Pregunta 45

Pregunta
Which of the following will bind to the DNA
Respuesta
  • Tryptophan
  • Phenylalanine
  • Tyrosine
  • Histidine

Pregunta 46

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

Pregunta 47

Pregunta
Duplex distortion in the PCRA substrate complex suggests a Passive unwinding system
Respuesta
  • True
  • False

Pregunta 48

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

Pregunta 49

Pregunta
Hexameric helicases can be part of the replisome
Respuesta
  • True
  • False

Pregunta 50

Pregunta
Hexameric helicases have a toroidal strcture to confer high processivity
Respuesta
  • True
  • False

Pregunta 51

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

Pregunta 52

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

Pregunta 53

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

Pregunta 54

Pregunta
ATP binding correlates with loop hight in the central channel
Respuesta
  • True
  • False
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