the muscle fiber

the actin filament

the myosin filament

columnar protein columns alongside the muscle fiber

kk

Actin, when polymerized into filaments, forms the "ladder" along which the myosin filaments "climb" to generate motion.

kk

jj

k

o

myosin is a contractile filament

titin and nebulin are structural proteins

contractile protein , Actin
-consists of 2 alpha helical strands of g-actin molecules bonded in series
-each g-actin has a binding site where the s1 fragment of the myosin cross-bridge complex binds during muscle contraction

-contractile protein, myosin
-consists of two heavy (form tail region and two cross-bridges that bind with actin to produce force) and four light chains (that influence cross-bridge cycling kinetics and therefore sarcomere contraction velocity

-contractile protein
-consists of two heavy (form tail region and two cross-bridges that bind with actin to produce force) and four light chains (that influence cross-bridge cycling kinetics and therefore sarcomere contraction velocity

Muscle contractile protein
Heart and muscle contractile fibres consist of bundles of actin polymers that slide alongside each other by the activity of the motor protein myosin and associated contractile proteins such as troponin and titin

Muscle contractile protein
Heart and muscle contractile fibres consist of bundles of actin polymers that slide alongside each other by the activity of the motor protein myosin and associated contractile proteins such as troponin and titin

regulatory proteins
proteins that help turn the muscle contraction process on and off

contractile proteins
proteins that produce force during muscle contraction

structural proteins
proteins that connect the outer layer of myofibrils to the sarcolemma, keep the actin and myosin filaments in proper alignment, and give the myofibrils their elasticity and extensibility

tropomyosin
-two per actin filament
-when muscle is relaxed, covers the myosin-head binding sites on the actin filament

troponin
-binds to both actin and tropomyosin
-has binding site for Ca+2 needed for muscle contraction
-located at the junction of each successive pair of tropomyosin molecules

titin
-stabilizes the alignment of the thick filaments by connecting each myosin filament to both the z line and the m line
-the titin that extends from the z line to the beginning of the myosin filament is believed to help keep the myosin filaments centered between the z lines
-helps the sarcomere return to its resting length after the muscle has contracted or been stretched, contributing to the myofibril's elasticity and extensibility

nebulin
-extends the length of each actin filament
-believed to anchor the actin filament to the z-line and help regulate the length of the actin filament

actin
-contractile protein
-consists of 2 alpha helical strands of g-actin molecules bonded in series
-each g-actin has a binding site where the s1 fragment of the myosin cross-bridge complex binds during muscle contraction

myosin
-contractile protein
-consists of two heavy (form tail region and two cross-bridges that bind with actin to produce force) and four light chains (that influence cross-bridge cycling kinetics and therefore sarcomere contraction velocity

proteins that help turn the muscle contraction process on and off

proteins that regulate bodily systems and are used in homeostasis

-is a contractile protein

-consists of two heavy (form tail region and two cross-bridges that bind with actin to produce force) and four light chains (that influence cross-bridge cycling kinetics and therefore sarcomere contraction velocity

is a myofilament , a filament of a myofibril

All of these are true

proteins that produce force during muscle contraction

proteins that bind with troponin

are centered with the M-line

proteins that build muscle

There are two per actin filament.
Tropomyosin, when muscle is relaxed, covers the myosin-head binding sites on the actin filament.

is a myofilament

has a calcium ion attached to it

is located in the neuromuscular junction