sperm cells

The result of this process is sperm cells ready to fuse with an egg.

In the course of a man's life, most of his sperm cells are ejaculated under conditions that offer no chance for a fertilization.

Amphibian sperm cells have yet to be cryogenically preserved; they too will need careful management.

However, in recent years it has become possible to extract sperm cells from the unexcited male sex organs by special medical procedures.

Italian scientists similarly found changes in mice testes (PDF), including damaged young sperm cells.

In the experiment, researchers "silenced" a gene called zpg needed for males to produce healthy sperm cells.

But undeveloped male sperm cells, called spermatogonia , do fine in a freezer.

Sperm cells begin as bundles of interconnected cells, shown here as masses of flowing green strands.

In seed plants it is the generative cell in the pollen grain, which divides in the pollen tube to produce two sperm cells.

One secondary spermatocyte divides and eventually grows into two sperm cells.

Not all bacterium have flagella and no human cells have them besides sperm cells.

The ovaries of the female produce egg cells, and the testes of the male produce sperm cells.

Egg cell and sperm cells. Schematic drawing showing their relative sizes.

Compatible pollen tubes reach the ovule where they burst and release the sperm cells.

Sperm cells must be produced for men to reproduce.

There' s millions of sperm cells, but only one will fertilize the egg.

Sperm cells are produced in the male gonads or sex glands ( testicles ).

The locomotion of sperm cells from pollen grain into the tube was examined by using the above technique.

Number of sperm cells produced ?

at puberty they are stimulated by hormones to develop into fertile sperm cells.

Once boys hit puberty, their sperm cells divide every 16 days.

"By the time a man is 40, his sperm cells have undergone 660 cell divisions, and 800 cell divisions by age 50, " he says.

It takes about 175, 000 sperm cells to weigh as much as a single egg cell.

what is known is that as men age , their ability to repair faulty dna in sperm cells decreases.

the vacuole-like structure in sperm cells could be the carrier of some genetic substances during fertilization;