BIOL 4100 Exam 4 Review
Actin binds Correct Answers ATP
Actin filaments
a. are polar
b. are non-polar
c. could be either polar or non polar Correct Answers a. are
polar
Antiparallel bundles... Correct Answers support molecular
motors
Consider formation of actin filaments.
Fn+G⟷Fn+1
For the plus end, the kon (i.e. association rate constant) = 10
µM-1s-1 and koff (i.e. dissociation rate constant) = 1 s-1.
Calculate KD of actin polymerization at the plus end of the
filament. Provide numerical answer in micromoles. Correct
Answers 0.1
Consider formation of actin filaments.
Fn+G⟷Fn+1
You have discovered a novel kind of actin. For the plus end and
T form:
kon (i.e. association rate constant) = 20 µM-1s-1
koff (i.e. dissociation rate constant) = 1 s-1.
For the minus end and D form
kon (i.e. association rate constant) = 5 µM-1s-1
koff (i.e. dissociation rate constant) = 0.5 s-1.
, Calculate treadmilling range for the novel actin. Provide
numerical answer in micromoles. Do not enter units into answer
boxes. Correct Answers lower boundary = 0.05
upper boundary = 0.1
Cytoskeletal component of filopodia is
a. parallel bundles
b. antiparallel bundles
c. microtubules
d. bundles of axonemal microtubules
e. stress bundles Correct Answers a. parallel bundles
Describe mechanism of chromosome mobility in Anaphase A
Correct Answers Kinesins depolymerize and shorten tubules
which causes chromosomes to move toward the spindle poles
along the kinetochore microtubules.
Describe mechanism of chromosome mobility is Anaphase B
Correct Answers The interpolar microtubules elongate and
push the spindle poles apart. The kinesins cross link with these
interpolar microbules and move towards the plus end causes
them to move in opposite directions.
Describe mechanochemical cycle of the myosin.
1. Name each stage of the cycle.
2. Describe what happens at each stage. Correct Answers 1.
Attached - the myosin is attached to the actin filament since
there is no nucleotide available
2. Released - ATP binds which causes a change in the
conformation of myosin which releases it from the actin
Actin binds Correct Answers ATP
Actin filaments
a. are polar
b. are non-polar
c. could be either polar or non polar Correct Answers a. are
polar
Antiparallel bundles... Correct Answers support molecular
motors
Consider formation of actin filaments.
Fn+G⟷Fn+1
For the plus end, the kon (i.e. association rate constant) = 10
µM-1s-1 and koff (i.e. dissociation rate constant) = 1 s-1.
Calculate KD of actin polymerization at the plus end of the
filament. Provide numerical answer in micromoles. Correct
Answers 0.1
Consider formation of actin filaments.
Fn+G⟷Fn+1
You have discovered a novel kind of actin. For the plus end and
T form:
kon (i.e. association rate constant) = 20 µM-1s-1
koff (i.e. dissociation rate constant) = 1 s-1.
For the minus end and D form
kon (i.e. association rate constant) = 5 µM-1s-1
koff (i.e. dissociation rate constant) = 0.5 s-1.
, Calculate treadmilling range for the novel actin. Provide
numerical answer in micromoles. Do not enter units into answer
boxes. Correct Answers lower boundary = 0.05
upper boundary = 0.1
Cytoskeletal component of filopodia is
a. parallel bundles
b. antiparallel bundles
c. microtubules
d. bundles of axonemal microtubules
e. stress bundles Correct Answers a. parallel bundles
Describe mechanism of chromosome mobility in Anaphase A
Correct Answers Kinesins depolymerize and shorten tubules
which causes chromosomes to move toward the spindle poles
along the kinetochore microtubules.
Describe mechanism of chromosome mobility is Anaphase B
Correct Answers The interpolar microtubules elongate and
push the spindle poles apart. The kinesins cross link with these
interpolar microbules and move towards the plus end causes
them to move in opposite directions.
Describe mechanochemical cycle of the myosin.
1. Name each stage of the cycle.
2. Describe what happens at each stage. Correct Answers 1.
Attached - the myosin is attached to the actin filament since
there is no nucleotide available
2. Released - ATP binds which causes a change in the
conformation of myosin which releases it from the actin
