Fertilised egg. Image 1 of 4. Light micrograph of a fertilised human egg cell, or zygote. This is the product of the joining of a female egg cell (ovum) and a single male sperm cell. The zygote is preparing to divide. This cell is the precursor of every cell in the new embryo. At this stage, the zygote travels down the woman's fallopian tube to the uterus. It will divide several more times before it implants in the uterine wall. For a sequence showing this embryo developing, see images P680/512-515. Magnification unknown.