I know sperm can live for 2-3 days, but how long for an egg to become completely fertilized?

Question

I read the other post about sperm living in the womans body for 3-5 days after ejaculation, that's not what I want to know. I want to know once a sperm has penetrated the egg, how long does that process take to turn into an embryo.

Answer 1

This site says
http://www.visembryo.com/baby/index.html

"Fertilization begins when a sperm penetrates an oocyte (an egg) and it ends with the creation of the zygote. The fertilization process takes about 24 hours.

A sperm can survive for up to 48 hours. It takes about ten hours to navigate the female productive track, moving up the vaginal canal, through the cervix, and into the fallopian tube where fertilization begins. Though 300 million sperm may enter the upper part of the vagina, only 1%, 3 million, enter the uterus. The next step is the penetration of the zona pellucida, a tough membrane surrounding the oocyte. Only one sperm needs to bind with the protein receptors in the zona pellucida to trigger an enzyme reaction allowing the zona to be pierced. Penetration of the zona pellucida takes about twenty minutes."

This site says
http://www.azrtl.org/human/human.htm

"Within 30 hours of insemination the first cell division takes place."

I think these quotes should answer both of your questions.
It takes about 10-24 hours before an egg is fertilized (including the sperm's traveling time) and within the first 30 hours it would actually be considered an embryo.

Answer 2

Once the sperm penetrates the egg, you can't get more fertilized than that. The cells will begin to divide right away, but it will take a couple days for the zygote to travel down the tube and implant into the uterine wall.

Answer 3

Since the definition of embryo is:

An organism in its early stages of development, especially before it has reached a distinctively recognizable form.
An organism at any time before full development, birth, or hatching.

I would say immediatly.

If you want to know how long it takes for the sperm to reach the egg after ejaculation, I have heard 90 seconds as an average. I am sure other people would say a different number.
HTH