Answer:
The myosin filament or more precisely the myosin head can now bind to the actin forming the cross bridges followed by a power stroke during which actin slides over myosin.
Explanation:
The muscle contraction can be explained by sliding filament theory bu Huxley and Huxley. The two muscle proteins which take part in muscle contraction are myosin and actin.
Myosin: It is a hexameric protein. Each monomer is called meromyosin. Each meromyosin has two important parts, a globular head with a short arm and a tail. The head forms cross bridges with the actin filament. Myosin head acts as ATPase enzyme. When ATP binds, head acts as enzyme hydrolyzing the ATP to produce energy. The head also has the site for binding of actin.
Actin filament: It contains three proteins, filamentous actin, tropomyosin and troponin. Filamentous actin contains active site for myosin binding but at rest, tropmyosin covers the myosin binding site. This prevents the cross bridge formation. Tropomyosin are held in place by troponin molecules.
When calcium is available, the binding of calcium to a TpC sub-unit of troponin causes the shifting of tropomyosin-troponin complex. Now actin can attach to myosin head and slide over myosin.
The actin filaments slide over the myosin filament by the the formation of cross bridges and during this process the I-band gets reduced whereas the A band remain the same. The lengths of actin and myosin filaments remain unchanged.
Answer:
species are the least closely related?
Number of Amino Acid Differences between Species
Species 1 Species 2 Species 3 Species 4
74
The taiga biome is the largest terrestrial biome and extends across Europe, North America, and Asia. It is located right below the tundra biome. The taiga biome is also known as coniferous forest or boreal forest. This biome typically has short, wet summers and long, cold winters. Precipitation is moderate in the taiga. It gets plenty of snow during the winter and plenty of rainfall during the summer.<span>Interesting Taiga Biome Facts:Fires are very common in the taiga biome. These fires are necessary to help rid the area of old and sick trees.There is not much variety in plants. Majority of the plants are conifer trees which is why the taiga is referred to as the coniferous forest.The conifer trees in the taiga biome are referred to as evergreen. This means they remain green all year round and never drop their leaves.<span>Because evergreen trees do not drop leaves, there is nothing to keep the soil in the taiga full of nutrients. This is the reason why there is not much variety in the vegetation. </span>Softwood timber is used to make paper. Majority of softwood timber comes from the taiga biome.<span>Although two major cities, Toronto and Moscow, are located in the taiga biome, most of this biome is uninhabited by people. </span>The taiga biome is very cold during the winter. Temperatures can reach as low as -60° F.For six months out of the year, the temperature in the taiga biome is below freezing.Plants can only grow during the summer when temperatures are favorable. This growing season only lasts about three months.Many animals of the taiga biome have to migrate to warmer areas or hibernate during the long, cold winters.Animals of the taiga have many specialized adaptions including lots of thick fur or feathers and the ability to change colors during different seasons.Scientists believe that the taiga biome was completely covered by glaciers many years ago.The taiga forests are endangered due to logging and mining by humans. When trees are cut down in the taiga, it takes a very long time to restore itself because of the very short growing season.Although there are not many animals in the taiga biome, it inhabits millions of insects. Birds migrate there to feed off these insects every year.<span>The temperature change in the taiga is extreme. It is either summer (hot) or winter (cold). The spring and fall are too short to notice.</span></span>
Answer:
It is the region of open sea beyond the edge of the continental shelf and includes 65% of the ocean's completely open water. The oceanic zone has a wide array of undersea terrain, including crevices that are often deeper than Mt. Everest, as well as deep-sea volcanoes and ocean basins.
Explanation:
