Exam 6: Cellular Movement and Muscles

Mollusc catch muscles are able to generate tension for long periods of time without consuming much energy.We do not understand everything about how this is accomplished,but there are unique proteins,such as __________,that seem to play a role.

In smooth muscle,bundles of filaments attach to the plasma membrane at points referred to as __________.

Microtubule growth will stop if

Which of the following pumps is specifically used to return Ca²⁺ to the sarcoplasmic reticulum?

When Ca²⁺ is present at high levels in the sarcoplasm of striated muscles,then

Compare smooth and striated muscles in terms of thick and thin filaments,calcium trigger,sarcoplasmic reticulum,regulation of contraction,and rate of contraction.

Insect flight muscles contract at frequencies much higher than the stimulation rates they receive from the nerves that innervate them.For this reason,they are termed __________ flight muscles.

Which of the following types of movement may NOT require use of a motor protein?

The sarcomere,or contractile unit of striated muscle,extends from one __________ to the next.

Muscle fiber types can be changed in response to

Contraction of striated muscle is regulated by

Microtubules are organized in cells with the ends near the nucleus in a region known as the __________,or MTOC for short.

An __________ contraction is one in which the length of the muscle does not change significantly.

The __________ explains how the myosin head moves down the actin polymer,generating movement.

Vertebrate striated muscles composed of twitch fibers are able to produce a graded contraction by

Skeletal muscle may be used in a __________ contraction.

Asynchronous flight muscles in insects are able to achieve contractions in the range of 250-1000 Hz because

Smooth muscle,like striated muscle,utilizes Ca²⁺ as a signal molecule that can allow contraction to occur.However,smooth muscle does not have troponin.Therefore,Ca²⁺ must interact with other proteins.Describe these relationships and then comment on how this alternate control system affects the rate and duration of smooth muscle contraction.

During which phase of an excitation-contraction cycle does depolarization occur?

In striated muscle,Ca²⁺ regulates contraction by interacting with troponin and tropomyosin.Explain how Ca²⁺ is able to regulate the timing of contraction as well as affecting the kinetics of contraction.