Sperm
hideThe 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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News tagged with sperm
Molecular Decay of Enamel-Specific Gene in Toothless Mammals Supports Theory of Evolution
Sep 04, 2009 |
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(PhysOrg.com) -- Biologists at the University of California, Riverside report new evidence for evolutionary change recorded in both the fossil record and the genomes (or genetic blueprints) of living organisms, ...
Unlocking the key to human fertility
Aug 03, 2009 |
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Scientists at Leeds and Bradford have discovered a unique 'DNA signature' in human sperm, which may act as a key that unlocks an egg's fertility and triggers new life.
Human sperm created from embryonic stem cells (Update)
Jul 08, 2009 |
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(PhysOrg.com) -- Human sperm have been created using embryonic stem cells for the first time in a scientific development which will lead researchers to a better understanding of the causes of infertility.
Analysis knocks down theory on origin of cell structure
Apr 22, 2009 |
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(PhysOrg.com) -- Understanding how living cells originated and evolved into their present forms remains a fundamental research area in biology, one boosted in recent years by the introduction of new tools ...
Stem cells battle for space
Dec 04, 2009 |
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The body is a battle zone. Cells constantly compete with one another for space and dominance. Though the manner in which some cells win this competition is well known to be the survival of the fittest, how stem cells duke ...
Sperm may play leading role in spreading HIV
Medicine & Health / HIV & AIDS
Oct 26, 2009 |
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Sperm, and not just the fluid it bathes in, can transmit HIV to macrophages, T cells, and dendritic cells (DCs), report a team led by Ana Ceballos at the University of Buenos Aires in Argentina. By infecting ...
Sperm donor passed on sudden death heart defect
Oct 20, 2009 |
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(AP) -- A sperm donor passed on a potentially deadly genetic heart condition to nine of his 24 children, including one who died at age 2 from heart failure, according to a medical journal report.
Putting the squeeze on sperm DNA
Sep 30, 2009 |
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(PhysOrg.com) -- In the quest for speed, olympic swimmers shave themselves or squeeze into high-tech super-suits. In the body, sperm are the only cells that swim and, as speed is crucial to fertility, have ...
Study Positively Identifies Giant Squid Presence in Gulf of Mexico
Sep 21, 2009 |
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(PhysOrg.com) -- During a recent research cruise, a rare giant squid was captured in the Gulf of Mexico.
Possible genetic factor for male infertility identified
Sep 15, 2009 |
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Virginia Commonwealth University School of Medicine researchers have discovered a gene involved with the production of sperm that may contribute to male infertility and lead to new approaches to male contraception.
Mother knows best: Females control sperm storage to pick the best father
Sep 08, 2009 |
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(PhysOrg.com) -- Scientists have found new evidence to explain how female insects can influence the father of their offspring, even after mating with up to ten males. A team from the University of Exeter has ...
Tunisian woman expecting 12 babies: reports
Aug 18, 2009 |
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A Tunisian woman is due to give birth to 12 babies, which could be a world record, press reports said Tuesday, quoting doctors.
Journal retracts claim of sperm made of stem cells
Jul 31, 2009 |
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(AP) -- A scientific journal has retracted a controversial paper claiming to have created the first human sperm from embryonic stem cells.
Mutation causing one type of male infertility found
Jul 21, 2009 |
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(PhysOrg.com) -- A genetic mutation that lies behind one type of male infertility has been discovered by researchers at Oxford University, Ghent University in Belgium, and the University of Massachusetts, ...
Sea lampreys jettison one-fifth of their genome
Jul 20, 2009 |
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(PhysOrg.com) -- Researchers have discovered that the sea lamprey, which emerged from jawless fish first appearing 500 million years ago, dramatically remodels its genome. Shortly after a fertilized lamprey ...
