Answer:
The source of Calcium (Ca⁺⁺) for the skeletal muscle cells is the sarcoplasmic reticulum, the main store of intracellular Ca⁺⁺.
Explanation:
Calcium (Ca⁺⁺) is an ion that plays an important role in muscle contraction, a process that requires high cytoplasmic concentrations of this ion to promote myofibrillary activity.
The sarcoplasmic reticulum (SR) -equivalent to the endoplasmic smooth reticulum- is an organelle that regulates the contractile activity of skeletal muscle. The two terminal cisterns of the SR attach to the T-tube, forming a triad, which surrounds the myofibrilla.
Once the muscle cell receives the signal to contract, the Ca⁺⁺ channels are opened and allow Ca⁺⁺ to enter the cell, promoting the exit of this cation from the SR and increased its cytoplasmic levels. This stimulates muscle contraction.
Transparent means all light can shine through. Common substances that are transparent are clear glass, clean water, and cellophane. Translucent means only some light can filter through the substance. Common translucent substances are tissue paper, the skin of your hand, and lamp shades. Opaque means little to no light passes through the substance. Common opaque substances are denim, cardboard, and leather.
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Answer: Option (a) is the correct answer.
Explanation:
It is known that weight is equal to mass times acceleration due to gravity.
Mathematically, Weight = mass × acceleration due to gravity
Since, it is given that weight is 34 N and it is known value of g is 9.8 m/s.
Therefore, calculate mass of the box as follows.
Weight = mass × acceleration due to gravity
34 N = mass × 9.8 m/s
mass = 3.47 kg
Hence, we can conclude that mass of the box is 3.47 kg.
