It permits calcium to leave the sarcoplasmic reticulum and enter the cytosol. During muscle contraction, the binding of acetylcholine initiates an excitatory impulse, which is transmitted to the deep of the muscle via T tubules. T tubules are the invaginations of cell membranes of muscle cells (sarcolemma). When the action potential travel down the t-tubules, they change shape and allow the calcium ions to enter into the sarcoplasm from the sarcoplasmic reticulum.
Tissues is the most basic organismal level, <span>which are groups of similar cells that act as a functional unit. </span>
An area where soil has eroded experience loss of nutrients. The topmost layer of soil is called the topsoil and is the most fertile. Soil erosion results in the loss of soil fertility and makes the land barren
The main cause of soil erosion is the removal of vegetation, which exposes the topsoil to water and wind. Wind and water are the main agents of soil erosion.
Water erosion can be sheet erosion, rill erosion, gully erosion or riparian erosion.
Answer:
The correct option is B: 2
Explanation:
Before meiosis takes place, the entire genetic material within the cell is replicated, this results in 2 copies of the 2n DNA. Since the person is heterozygous for the mutated allele, there is one copy of it present within one 2n set of chromosomes. Two of the 2n chromosomal sets means there would be two copies of it present in total and when the segregation event happens to create haploid cells, two of the cells will inherit the mutated copy.
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