Myosin

1. Skeletal muscle used ATP to contract. Then, ATP is broken down into ADP and P, which release energy. 2. A) The sarcoplasmic reticulum is the organelle that stores calcium in muscles cells. B) In order for calcium to be released from this organelle some events must occur. First, an action potential needs to reach the synaptic terminal. Then acetylcholine needs to be released into the sarcoplasm. After that, ACH molecules will land on receptors that are on the motor end plate. Then, an action…

Figure 1 Myosin and actin work together to generate motion within skeletal muscles, however, a vital means of communication, uniting motor neurons and muscles, must be present prior to movement. Tropomyosin and troponin maintain control over the contractions produced by myosin and actin and provide an essential outlet for dictating instructions. Tropomyosin, a two-stranded, alpha-helical coil protein, is positioned laterally along actin filaments and is responsible for “blocking” myosin heads…

body parts, manipulation of external objects, support for our skeleton (Sherwood, 2010, p257). Skeletal muscles have a striated structures of alternating light and dark bands (Sherwood, 2010, p258). A bands, which are dark and primarily composed of myosin, and I bands, that are light are primarily composed of actin filaments (Sherwood, 2010, p258). The interaction of these bands is responsible for muscle contraction. Muscle cells,…

1. The resting membrane potential is the potential difference across the cell membrane of excitable cells such as nerve and muscle cells. The 3 major factors that establish a resting membrane potential are as follows: (1) Non-diffusible anions: The resting membrane potential is influenced by the presence of large non-diffusible anions (proteins, nucleic acids and organic phosphates) inside a cell. The presence of large non-diffusible anions inside a cell attracts a large number of cations and…

resistance and act as a transcription factor to promote ‘slow’ genes. Slow twitch muscle fibers also have slow Calcium ATPase and lower activity myosin ATPase, which both work to cause longer contractions. Fast twitch, type II, fibers are the opposite of slow twitch fibers and involve more anaerobic activity. They have fast Calcium ATPase and High activity Myosin ATPase causing shorter, faster contractions. These muscles have three types; IIa, IIb, and IIx/d. Type IIb fibers are fast and…

contraction. Myofibrils are protein bundles containing actin and myosin. Actin (thin) and myosin (thick) make up a unit of skeletal muscle cell called a sarcomere, the main unit of contraction in skeletal muscle cells. The patterns of sarcomeres make up the striations or the stripe like feature of the cell. The actin and myosin in the sarcomere use what is known as the sliding filament theory as means of causing the contractions of muscle. Myosin slides along actin filaments to contract a…

body recruits different muscle fibers for different activities. The first muscle fiber to be recruited are slow twitch fibers, are also known as Type I. “Slow twitch muscle fibers are the smallest in diameter, contain the least amount of actin and myosin, and allow…

independent units because there are few, if any, gap junctions (Hill et. al 2016). This would be used to describe a large artery or vein (Hill et. al 2016). Like skeletal muscles, smooth muscles use the contractile proteins actin (thin filament) and myosin (thick filament); however, these proteins are not arranged into sarcomeres, so the cells do not appear striated. These thin and thick filaments interact with each other in the presence of calcium (Ca²⁺) in order to form cross bridges. The…

calcium ions can easily bind to the protein troponin located on an actin filament, which causes a shift in the thread-like protein tropomyosin. This ultimately exposes the active sites on the actin filament, allowing the contractile filaments actin and myosin to form a…

while warmer conditions accelerated the rate at which a muscle fatigues, which agreed with my hypothesis. Maximal contractile forces within a skeletal muscle are regulated by the force-length relationship, and the optimal overlap of actin and myosin filaments that produce the greatest force within the muscle. A muscle produces its greatest force when it is at its optimal or resting length, and its lowest force when the fibers are stretched or shortened. Contractile forces are regulated by…