Related topics: eggs · fertilizer · genes · infertility · females

Scientists mail freeze-dried mouse sperm on a postcard

Scientists no longer have to worry about their bottles of mouse sperm breaking in transit. Researchers in Japan have developed a way to freeze dry sperm on a plastic sheet in weighing paper so that samples can withstand being ...

Evolution of the Y chromosome in great apes deciphered

New analysis of the DNA sequence of the male-specific Y chromosomes from all living species of the great ape family helps to clarify our understanding of how this enigmatic chromosome evolved. A clearer picture of the evolution ...

The limits of ocean heavyweights: Prey curb whales' gigantic size

At 100 feet long and weighing more than 100 tons, blue whales are the largest creatures to have evolved on the planet. Other whales, like killer whales, are larger than most terrestrial animals but pale in comparison to the ...

Female flies respond to sensation of sex, not just sperm

Female fruit flies can feel when a sexual partner is a good fit. Scientists have long known that proteins in a male fly's ejaculate make female flies temporarily lose interest in other partners. It's a trick male flies use ...

Rice plants that grow as clones from seed

Plant biologists at the University of California, Davis have discovered a way to make crop plants replicate through seeds as clones. The discovery, long sought by plant breeders and geneticists, could make it easier to propagate ...

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Sperm

The term sperm is derived from the Greek word (σπέρμα) sperma (meaning "seed") and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell. The human sperm cell is haploid, so that its 23 chromosomes can join the 23 chromosomes of the female egg to form a diploid cell. A uniflagellar sperm cell that is motile is referred to as a spermatozoon, whereas a non-motile sperm cell is referred to as a spermatium. Sperm cells cannot divide and have a limited life span, but after fusion with egg cells during fertilization, a totipotent zygote is formed with the potential to develop into a new organism.

The spermatozoa of animals are produced through spermatogenesis inside the male gonads (testicles) via meiotic division. They are carried out of the male body in a fluid known as semen. Mammalian sperm cells can live for up to 3 days inside the female reproductive system.[citation needed]

Sperm cells in algal and many plant gametophytes are produced in male gametangia (antheridia) via mitotic division. In flowering plants, sperm nuclei are produced inside pollen.

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