What is the function of calcium ions during muscle contraction

The calcium ions play a major role in providing muscle contraction. The calcium ions are released by sarcoplasmic reticulum in the phenomenon of muscle contraction. For allowing a muscle to contract, the calcium ions binds to the troponin, which is a complex of protein. As a result of this binding, the active binding sites of the actin microfilaments gets exposed. Gaps are formed, which are readily filled by the myosin. As a result, cross- bridges is formed which allows the muscle to contract.

both male and female gametes are produced by meiosis of the germ cells. therefore, both male and female gametes are haploid. one male and one female gamete unite during the fertilization to form the diploid zygote. in seed bearing plants, pollen grain is the male gametophyte, which produces sperm cells.