Lecture 10: Muscular Tissue Part 2 Flashcards
muscles generate force by?
muscle contraction
3 types of proteins involved in muscle contraction?
contractile proteins, regulatory proteins, and structural proteins
Contractile proteins?
proteins that work to shorten the sarcomere.
- Myosin
- Actin
Myosin?
- motor protein
- each thick filament consists of 300 myosin proteins
- myosin heads extend from the end of thick filaments = contact thin filaments = pull thin filaments towards the m-line
myosin head?
each myosin has an atp binding site and an actin binding site
Actin?
- cytoskeleton protein
- long threads are twisted around one another to form helical thin filaments
- have myosin binding sites
Regulatory proteins?
proteins that associate with thick and thin filaments to control contraction
- troponin
- tropomyosin
troponin?
binds calcium and moves tropomyosin
tropomyosin?
blocks myosin binding sites on thin filaments
Structural proteins?
proteins that stabilize and connect the sarcomere and surrounding structures.
- titin
- dystrophin
titin?
large elastic protein that spans the m line to z discs
dystrophin?
connects thin filaments to integral membrane proteins in the sarcolemma
muscle contraction by sliding filament model?
the sarcomere shortens as the thin filaments slide over the thick filaments
what happens in the contraction cycle?
1) myosin binds and hydrolyzes ATP
2) myosin binds thin filaments to form a cross bridge
3) myosin pulls the thin filaments towards the M-line
4) myosin releases the thin filaments
5) requires binding of new ATP molecule to myosin so new cycle can begin
the conformational change when myosin pulls thin filaments towards the m line is called ?
power stroke
