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MCB 150 EXAM 3 UIUC 2026
QUESTIONS AND ANSWERS| ACE
YOUR GRADES.
Actin networks - correct answer -provide structural stability, but
are more flexible than bundles, actin network is dynamic
Actin filaments promote movement in a cell, but movement
requires a motor protein which is what? - correct answer -myosin
Myosin - correct answer -molecular motor that converts chemical
energy (ATP) into mechanical energy generating force and
movement
What can action and myosin do? - correct answer -responsible for
cell division, cell crawling, some vesicle movement, and muscle
contraction
Filament sliding process - correct answer -1. Myosin head group
has a nucleotide sequence binding site for ATP
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2. ATP binds to myosin head site
3. Myosin lets go of actin
4. ATP gets hydrolyzed to ADP and phosphate (both of these
pieces are still in nucleotide binding site of myosin head group)
5. Head group of myosin is linked up with different monomer in
actin
6. Relative to where we began we are a little closer to barbed end
on actin
7. ADP myosin has a small affinity for actin and will eventually
make contact with next G actin monomer and when it does it
grabs on weakly
8 .this rejects the phosphate group
9. Triggers powerstroke and ADP is ejected out and you are back
to where you started (rigor)
Cell crawling - correct answer -movement of cells along its
substratum by myosin and actin
Cell crawling process - correct answer -1. Begins by pushing out
leading edge of cell through polymerization of actin network
2. Attachment of extended leading edge to substratum done by
attachment molecules
3. Move entire cell body forward
4. Myosin grabs onto actin filaments and starts contracting
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5. When myosins move relative to the actin, they will essentially
pull everything else in the cell forward
6. Retraction of the trailing edge, so cell doesn't keep spreading
thinner and thinner
7. Detach from point of attachment in back and cytoplasm will
rejoin the rest of the cell, snapping right into place
Unconvential myosin - correct answer -not attached to action,
cannot form thick filaments, still barbed end directed myosin
Most, but not all myosin is directed which way? - correct answer -
barbed end directed
Light band is same as - correct answer -I band
Z disc - correct answer -dark line through middle of I band
Thin filament - correct answer -f actin
MCB 150 EXAM 3 UIUC 2026
QUESTIONS AND ANSWERS| ACE
YOUR GRADES.
Actin networks - correct answer -provide structural stability, but
are more flexible than bundles, actin network is dynamic
Actin filaments promote movement in a cell, but movement
requires a motor protein which is what? - correct answer -myosin
Myosin - correct answer -molecular motor that converts chemical
energy (ATP) into mechanical energy generating force and
movement
What can action and myosin do? - correct answer -responsible for
cell division, cell crawling, some vesicle movement, and muscle
contraction
Filament sliding process - correct answer -1. Myosin head group
has a nucleotide sequence binding site for ATP
, Page | 2
2. ATP binds to myosin head site
3. Myosin lets go of actin
4. ATP gets hydrolyzed to ADP and phosphate (both of these
pieces are still in nucleotide binding site of myosin head group)
5. Head group of myosin is linked up with different monomer in
actin
6. Relative to where we began we are a little closer to barbed end
on actin
7. ADP myosin has a small affinity for actin and will eventually
make contact with next G actin monomer and when it does it
grabs on weakly
8 .this rejects the phosphate group
9. Triggers powerstroke and ADP is ejected out and you are back
to where you started (rigor)
Cell crawling - correct answer -movement of cells along its
substratum by myosin and actin
Cell crawling process - correct answer -1. Begins by pushing out
leading edge of cell through polymerization of actin network
2. Attachment of extended leading edge to substratum done by
attachment molecules
3. Move entire cell body forward
4. Myosin grabs onto actin filaments and starts contracting
, Page | 3
5. When myosins move relative to the actin, they will essentially
pull everything else in the cell forward
6. Retraction of the trailing edge, so cell doesn't keep spreading
thinner and thinner
7. Detach from point of attachment in back and cytoplasm will
rejoin the rest of the cell, snapping right into place
Unconvential myosin - correct answer -not attached to action,
cannot form thick filaments, still barbed end directed myosin
Most, but not all myosin is directed which way? - correct answer -
barbed end directed
Light band is same as - correct answer -I band
Z disc - correct answer -dark line through middle of I band
Thin filament - correct answer -f actin
