Spring 2018 6. Cytochalasin B strongly inhibits certain forms of cell motility.
ID: 204466 • Letter: S
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Spring 2018 6. Cytochalasin B strongly inhibits certain forms of cell motility. In classic experiments that defined its mechanism, short lengths of actin microfilamentsminus were decorated with myosin heads and then mixed with actin subunits above the critical concentration in the presence (+) or absence () of cytochalasin B. Assembly of actin microfilaments was assayed by examining samples by electron microscopy. The figure to the right shows results describing the appearance of actin microfilaments formed in the presence and absence of cytochalasin B. The decorated actin microfilaments (gray circles + lines) present before the addition of actin monomers are shown at the top of each set of three. Microfilaments present after increasing times of incubation with actin monomers (red circles) are shown in the next two rows. ochalasin 8 phus A. (3pts) Please propose a molecular mechanism for how cytochalasin B affects the dynamics of actin microfilaments that is consistent with the EM 9 data. B. (2pts) Why was it informative to decorate the actin microfilaments with myosin heads before adding mixing with actin subunits? 0 7. (4pts) Many transport vesicles carry both kinesins and dyneins. Please provide a reason why this might be the case. 9Explanation / Answer
In the diagram this idea is given that cytochalasin B inhibits the polymerization of actin protein at positive end as well as negative end.
when we add cytochalasin B in the system then we observe that polymerization of actin is reduced.
actin protein and myosin protein is responsible for muscle contraction by interaction with each other.
when actin polymerises at particular level then it interacts with myosine protein and allows muscle contraction or movement.
Hence polymerization of actin is necessary.
a. cytochalasin B binds at the positive end and nnegative end of the growing actn chain and inhibits the binding of monomeric globular actin.
When monomeric globular actin not binds with the actin chain than polymerization of actin inhibited.
Actin is not completely synthesized than not able to interact with myosin.
b.
As we know that actin protein interacts wiwith myosin and then do interaction for muscular movement.
7. Kinesin and dynine are motor protein which allows the movement of vesicle from one part of cell to another part of the cell.
Vesicles walk on the microtubules track by the help of kinesin and dynine.
I answered the questions according to chegg guidelines for more you have to upload Each question separately.
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