Transitional B cells bound for a follicular fate undergo positive and negative selection in the spleen.

TLS Online TPP Program

#Id: 8397

#XL - Q Biochemistry

Z disk 

Thin actin filaments are assembled with their (+) ends embedded in a densely staining structure

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#Id: 8396

#XL - Q Biochemistry

Each sarcomere contains two major types of filaments: 

Thick filaments (myosin II)

Thin filaments (actin and associated proteins)

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#Id: 8395

#XL - Q Biochemistry

Sarcomere

Within each skeletal muscle cell are many myofibrils consisting of a repeating array of a specialized structure

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#Id: 8394

#XL - Q Biochemistry

When the Ca2+ levels drop:

Myosin LC is dephosphorylated by MLC phosphatase, causing muscle relaxation.

TLS Online TPP Program

#Id: 8393

#XL - Q Biochemistry

Phosphorylation of MLC 

unfolds the myosin II, active and can assemble into bipolar filaments for contraction

TLS Online TPP Program

#Id: 8392

#XL - Q Biochemistry

The CaM*-Ca2+ complex binds and activates MLC kinase, phosphorylates the myosin LC.