add radiolabeled actin subunits to a mixture of actin filaments in which conditions are favorable for polymerization.
Considering that Amoeba sp., among other animal cells, possesses the capacity of dynamic surface extensions containing actin filaments. These filaments produce pseudopodia-stubby distensions of the actin cortex-with which they walked over surfaces. Therefore if there is an interest in slowing down the movement we would have to be interested in fibroblast cells that regularly extend a thin, sheetlike process known as lamellipodium, which contains a dense meshwork of actin filaments. Moreover, actin filaments can form the so-called microspikes, which are about 0.1 um wide and 5 to 10 um long and contain a loose bundle of about 20 actin filaments oriented with their plus ends pointing outward. In conclusion, it will be a good idea to look at the actin protein in order to make a research in amoeba's locomotion processes.
Under high magnification, you would observe the distinct bands of a sarcomere including the dark A band (containing thick filaments), the light I band (containing thin filaments), the Z line in the center of the I band, and the H zone in the middle of the A band. This level of magnification would also reveal the arrangement of actin and myosin filaments within the sarcomere.
The cytoskeleton is the scaffolding of a cell. It is composed of microtubules, actin filaments, spectrin tetramers, and intermediate filaments. Without this framework, the cell would collapse.
Without ATP, the myosin heads would remain bound to actin filaments as they lack the energy to detach, preventing further cross-bridge cycling. As a result, muscle contraction would be halted in the shortened state, leading to muscular rigidity or cramping.
If one were examine any type of muscle cell at the molecular level, what one would find is some kind of structured array of very thin (nano-scale) chains of protein called myofilaments.These are the smallest contractile elements in muscle tissue. There are two kinds of myofilaments: the thin actin filaments (~7 nm diameter), and the thicker myosin filaments (~16 nm diameter).In the case of skeletal and cardiac muscle these filaments alternate many times in parallel to the axis of muscle contraction.During muscle shortening, the job of myosin is to latch on to points along the actin filaments and pull them closer toward each other. During relaxation and muscle lengthening the gap between adjacent actin filaments increases.The muscle cells that are responsible for contracting sphinctors, blood vessels, bronchioli, the iris, and providing gut motility are a bit different. These are called smooth muscle cells. Instead of having a regular array of filaments parallel to axis of force-generation, they are arranged irregularly in a sort of criss-cross fashion that 'squishes' the cell as it contracts.
The cytoskeleton, particularly actin and the more stable intermediate filaments, are what mainly determines the shape of the cell, along with hydrostatic pressure from the water-containing cytoplasm.
A drug that interferes with cross-bridge formation would prevent the myosin heads from binding to actin filaments, impairing the sliding filament mechanism essential for muscle contraction. This would result in a decrease in muscle force generation and overall muscle contraction efficiency.
We would die. Just die. Cause muscles wouldn't function without actin. I think. So yeah. Spoken as a high school biology student
The area of the sarcomere containing the thick filaments is known as the A band. It appears dark under a microscope due to the overlapping thick filaments. The A band also includes some thin filaments at its edges where they overlap with the thick filaments.
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Acetylcholine release is necessary for skeletal muscle contraction, because it serves as the first step in the process, enabling the subsequent cross-bridge formation. A muscle's ability to contract depends on the formation of cross-bridges between myosin & actin filaments. A drug that blocks acetylcholine release would interfere with this cross-bridge formation and prevent muscle contraction
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