Striated muscles contain repeating sarcomeres of overlapping arrays of long, thin actin and thicker myosin filaments. Myosin filaments contains the myosin heads, which are enzymes that can bind to actin, split and make use of the energy from ATP. When muscle contraction starts, myosin heads bind to actin, change their configuration on actin, liberating the products of ATP hydrolysis and causing slide of the actin and myosin filaments. The action of the proteins troponin and tropomyosin on the actin filaments regulates vertebrae striated muscle contraction. The release of calcium ions from the sarcoplasmic reticulum is triggered by the nervous stimulation which causes depolarization of muscle membrane. Calcium ions bind to troponin and thus cause or allow the tropomyosin strands on the actin filament to move so that the part of the actin surface where myosin heads need to bind is uncovered. Contraction then occurs and only stops when the sarcoplasmic reticulum pumps calcium out of the muscle interior.
So basically, what triggers the uncovering of the myosin binding site on actin is the calcium ions binding to troponin and changing configuration.
Generally people would say that the result are published in journals, and it is true that Journals are often the first opportunity for many people to read about those results.
However, it takes a long time to publish in a journal, and people often present their results to a smaller audience at a conference before the journal is ready.
<u>Answer:
</u>
The day one starts with the first day of your periods when the blood and tissue lining the uterus (womb) break down and leave the body is considered to be the '1st day' of the 'female reproductive system'.
<u>Explanation:
</u>
- The periods, that is the 'first day of female reproductive system' starts during puberty and stops 'permanently at menopause'.
- The menstrual cycle starts with the 'first day of bleeding', which is counted as 'day one'.
- The menstrual cycle stops just before the "next menstrual period". Menstrual cycle normally ranges from 25 to 36 days.
- The periods may last anywhere from '3 to 8 days', but '5 days' is average.
The level of organization that describes an anchovy school is community.
<h3>What is a community?</h3>
Communities can be defined as sets of populations, that is, a community is formed by organisms that live in a given area in a given period of time. Thus, the community differs from the population for being constituted by groups of organisms of more than one species.
With this information, we can conclude that the level of organization that describes an anchovy school is community.
Learn more about anchovy school in brainly.com/question/1079705referrer=searchResults
#SPJ4
