<Li> a thin cell membrane covering the axoneme </Li> <Li> mitochondria arranged spirally around it the axoneme, </Li> <P> Back and forth movement of the tail results from a rhythmical longitudinal sliding motion between the anterior and posterior tubules that make up the axoneme . The energy for this process is supplied by ATP produced by mitochondria . The velocity of a sperm in fluid medium is usually 1--4 mm / min . This allows the sperm to move towards an ovum in order to fertilize it . </P> <P> In mammals, spermatozoa mature functionally through a process which is known as capacitation . When spermatozoa reach the isthmic oviduct, their motility has been reported to be reduced as they attach to epithelium . Near the time of ovulation, hyperactivation occurs . During this process, the flagella move with high curvature and long wavelength . Hyperactivation is initiated by extracellular calcium; however, the factors that regulate calcium level is unknown . </P>

Where do sperms get the energy required to keep the flagella moving