It only takes about three to four days for the blastocyst (post-zygote stage) to attach itself to the uterin wall. Until then, most of the energy comes from the sperm, which is almost completely made up of carbohydrates.

Remember that during this initial division state, the cells only divide…they really don’t start growing until the placenta is formed.

What kyle said goes for humans. Do you need info only on that or in the living world in general?

What about the egg.. Doesn’t the egg give any energy too? the sperm cell can’t just do it all by hisself can it?

Eggs are formed at the birth of the mother. And since it is propelled though the female’s reproductive tract, it doesn’t need very much energy other than to exist. It doesn’t move, it doesn’t do much of anything, so it doesn’t have need to produce energy.

Contrast this to chicken eggs which receive no nutrition from the mother and are therefore packaged with much nutrition for the baby.

Actually the blatocyst does not attach for 9-10 days–soon after the placenta is formed to give nutrients–before this the embryo is sustained with estrogen and progesterone–

What is your source, abharris? Mine said 3-4 days.

Also, I do find it difficult to understand how messenger chemicals and metabolism regulating chemicals…hormones…are able to supply energy.

Last I checked, Adrenaline makes your body create energy more quickly…not give it to you directly.

During a normal, healthy pregnancy the newly formed zygote that exists after fertilization lodges itself into the wall of the uterus. The woman’s uterus begins immediately to supply the zygote with blood. This is what gives the zygote energy to begin dividing itself via the process of mitosis. The original cell that was created from fertilization will divide to create two cells, which will then divide to create four cells, and so on for months. At the end of the process a newborn baby will be birthed by the mother, comprised of millions of cells that all sprung forth from the simple zygote that was created during fertilization.

Read more: Where Does Fertilization Take Place? | eHow.com http://www.ehow.com/how-does_4586310_do … z1RsLXJowG