Thick and thin myofilaments have different compositions. For each descriptive phrase, indicate whether the filament is, a. thick or b. thin.  _____ (1) contains actin  _____ (2) contains ATPases  _____ (3) attaches to the Z disc  _____ (4) contains myosin  _____ (5) contains troponin  _____ (6) does not lie in the I band

Video transcript

Everyone. Let's take a look at this question together which of the following statements about muscle contraction is true. Is it answer choice. A myosin filaments slide along acting filaments during muscle contraction. Answer choice batp is produced during muscle contraction. Inter choice C, Troponin and Tropomyosin are components of the myosin filament or answer choice D the I band remains the same length during muscle contraction. Let's work this problem out together to try to figure out which of the following statements about muscle contraction is true. So, in order to determine which of the following statements is true, we have to recall what we've learned about what occurs during muscle contraction. And we note that in muscle contraction, the myosin filaments slide past the acting filaments which results in the sarcomere shortening. Thus, the entire muscle fiber shortens. And we also know that in muscle contraction A TP is required. However, it is not produced. We know that the thin filaments contain troponin, an Tropomyosin. And lastly, the I band which contains only act in shortens. However, the A band which contains both acting and Myosin remains the same length. So now that we've recalled what we've learned about muscle contraction, we can determine which of the following statements is true. Since we know that A TP is required but not produced, we can eliminate answer choice B we note that Troponin and Tropomyosin are components of the thin filaments which are the acting filaments and not the myosin filaments. So answer choice C can be eliminated. And lastly, we note that the I band is the band that shortens whereas the A band remains the same length. So answer choice D can be eliminated, leaving us with the correct answer, which is answer choice. A the myosin filaments slide along the acting filaments during Mussa contraction, which is a true statement. So it is the correct answer since answer choice A describes the process known as the sliding filament theory of muscle contraction. And it is the only true statement. I hope you found this video to be helpful. Thank you and goodbye.