Sperm fertilising an egg. Cutaway artwork of a human sperm cell (spermatozoon) penetrating an egg cell's (ovum) thick outer layer (zona pellucida). The egg cell's membrane is at top right. Once inside the ovum,the sperm cell will release the genetic material (deoxyribonucleic acid,DNA) in its head (acrosome) to mix with the DNA in the ovum. The diagram here shows: mitochondria (at base of tail,blue),the protein K81 (base of head,light blue),DNA-containing chromosomes with centromeres (blue with green spheres),m-RNA (messenger ribonucleic acid,yellow),and the proteins lzumo (red) and PLC-zeta (pink) |