The cross bridge cycle is a series of molecular events that occur after excitation of the sarcolemma. what is a cross bridge?

The cross-bridge cycle is part of the process of muscle fiber contraction analysis of a set of steps:

1) Excitation of skeletal muscle fiber - involving the unleash the potential for action and its spread throughout the Sarcolemma.

2) Excitation/contraction coupling, which includes the processes of excitation transduction in contractile vegetation.

3) Cross bridges cycle, responsible for cyclic formation and rupture complexes of action and the generation of force and mechanical work.

4) Muscle Relaxation - A contraction of muscle fiber in response to a single action potential.

In the Cross Bridges Cycle, actin and myosin myofilaments do not change in length during contraction of the skeletal muscle. Instead, the myofilaments actin and myosin glide along with each other in a way that takes shortening of the sarcomere. During contraction, bridges are formed between the actin molecules and the heads of the myosin molecules. As bridges form, move, break free and reform in a way similar to paddling a boat. The voluntary movement of the bridges makes actin myofilaments at each end of the sarcomere slide to beyond myosin myofilaments towards the H-zone. Bands I and zones H become narrower, but bands A keep a constant length. Zone H may disappear when Actin myofilaments overlap in the center of the sarcomere. When actin myofilaments slide over the myosin myofilaments, the lines Z approach and the sarcomere shortens.

kelp are large brown algae that live in cool, relatively shallow waters close to the shore. they grow in dense groupings much like a forest on land. these underwater towers of kelp provide food and shelter for thousands of fish, invertebrates, and marine mammal species.

e) all of the above

it has to be understood that the sea water contains a huge amount of sodium and chlorine ions and if they enter the cell of the atlantic cod fish, the cell will shrivel and the fish will die. to avoid such a condition, the fish uses active transport for the purpose of removing the ions against the gradient.

explanation:

the atlantic cod is not a maritime osmoconformer. its native application of salts is less than that of the seawater it lives in. it is continually falling water from the gills to the ocean via osmosis.

countering that, the fish is going to be swallowing seawater. but since its internal collection of salts is lower than seawater, the fish will want to go free of excess salt, and since that's going upon a gradient, then active transport, requiring energy, must be used to pump out the salt. much marine fish use the organs to filter out the salt and these fish discharge very straight urine.