BIO304H5 Lecture : #21 Muscle

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emeralddog909

16 Dec 2011

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Myosin and actin filaments two main parts of the banding parten of the sarcomere. Attachment on the z disk and makes an association with the actin filament. Green line in the middle is called m line. One end of a myosin filament to another yosin filament with actin inside the range and the z disk right in the middle of it. One binds one actin, and the other a-actin binds to another actin and they are binded together. Cap z: caps the actin to stop it from getting longer, stopping it at that region within the z-disk. M-protein provides a structural link from one myosin to another myosin, keeping them the right distance apart. Addition of shortened sarcomere (each sarcomere contraction is very little. Contraction :higher degree of overlap between thin and thick filaments. Z disk distance shorter when contracted (the blue lines) Titin plays an important role in the structure.

Related Questions

interactions between actin and myosin filaments of the sarcomere are responsible for

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If a myofibril were pulled so that the sarcomeres increased in length by approximately 50 percent, what effect would you expect this to have on the contractile ability of the myofibril? Why? What effects would this have on the H, A, and I bands?

Myosin II action (Figure 9.61) differs from that of kinesin (Figure 9.15) in that one of the kinesin heads is always in contact with a microtubule, whereas both myosin heads become completely detached from the actin filament. How are these differences correlated with the two types of motor activities in which these proteins engage?

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1)Describe the directions in which the two motor proteins, kinesin and dynein, travel along a microtubule. Which of the two proteins moves materials towards the Golgi and which moves materials away from the Golgi? Lastly, what is the speed of kinesin dependent on?

2)What are microfilaments crucial for? How do they self-assemble? Which end do they prefer to elongate from?

3)Describe what types of filaments are in each of the bands of the sarcomere. As a muscle fiber is shortened, describe what happens to each of the bands in the sarcomere as the Z lines move inwards.

4)Describe the role of calcium ions in muscle contraction.

5)List the various types of actin-binding proteins

6) A. What are 3 functions of the cytoskeleton?

B.What are the three filaments that compose the cytoskeleton, and what are they composed?

7)How do they see the internal structures of cells in the microscope? What do proteins get labeled with?

8)Myosin II action (Figure 9.61) differs from that of kinesin (Figure 9.15) in that one of the kinesin heads is always in contact with a microtubule, whereas both myosin heads become completely detached from the actin filament. How are these differences correlated with the two types of motor activities in which these proteins engage?

9)If a myofibril were pulled so that the sarcomeres increased in length by approximately 50 percent, what effect would you expect this to have on the contractile ability of the myofibril? Why? What effects would this have on the H, A, and I bands?

10)Because cytoplasmic vesicles are seen to move in both directions within an axon, can you conclude that some microtubules are oriented with their plus end facing the axon terminus and others oriented with the opposite polarity? Why or why not?

BIO304H5 Lecture : #21 Muscle

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