Biology question

[wildchild]

I have a question i would like to ask about making babies if you hav any experiance please read on - this is really for my own interest nothing else.

Can more than one sperm penetrate an egg at once? if so what happens if its sperm from 2 different men. I know sperm from 2 different men can penetrate 2 seperate eggs in a women ( if the women produces 2 at once ) but can 2 sperm inseminate one egg is this possible?

 

[check_mate_kid_uk]

no they cant, although there may have been some freak cases where it has, but you would have to google that to find out.

as for women haveing 2 eggs at once, again i think that would be freak cases thats not a normal or lightly tihng to happen, i didnt even know that it can happen.

 

[California Love]

I don't think it can happen. If it would, what you would get is a triploidy offspring (which does happen in nature), meaning they have three of each chromosome instead of a pair.


1) The child would be sterile, because they cannot undergo meiosis to form gametes.

2) There would also be sex-chromosome disorders.

-Klinefelters syndrome (XXY). Basically, u have a really feminine male with small sex organs and an androgynous body.

-Trisomy (XXX). These are females. They have no problem whatsoever, because onely one X chromosome is active in females. Any other become what are called "barr bodies" which are inactive. Think mummies versus live people.

 

[check_mate_kid_uk]

i forgot all my biolgy, havent done it for over half a year but that is a dam good point, although the egg could just choose the dominant sperms chromosones to do meosis with.

 

[wildchild]

I know for a fact that 2 different mens sperm can penetrate 2 eggs from the same women at the same time and make the twins children of 2 seperate fathers, as far as i know identicle twins are made for 1 egg that splits in 2 and non identicle twins are made from 2 sperm and 2 eggs from the same father. Theres a name for 2 eggs and 2 different guys sperm making 2 seperate kids at the same time i think it begins with the letter "F" like children in the past have been born with a twin brother that is a different race from them because of this.

 

[check_mate_kid_uk]

Originally posted by wildchild
I know for a fact that 2 different mens sperm can penetrate 2 eggs from the same women at the same time and make the twins children of 2 seperate fathers, as far as i know identicle twins are made for 1 egg that splits in 2 and non identicle twins are made from 2 sperm and 2 eggs from the same father. Theres a name for 2 eggs and 2 different guys sperm making 2 seperate kids at the same time i think it begins with the letter "F" like children in the past have been born with a twin brother that is a different race from them because of this.

that is BS the reason twincs can be non identicle is because diffent chromosomes can be given from each parent. There are not 2 eggs.

 

[California Love]

Originally posted by check_mate_kid_uk
that is BS the reason twincs can be non identicle is because diffent chromosomes can be given from each parent. There are not 2 eggs.

Sorry to burst your bubble bro. She's correct.

Identical twins - split egg

Fraternal twins - 2 eggs, 2 sperm

 

[check_mate_kid_uk]

Originally posted by California Love
Sorry to burst your bubble bro. She's correct.

Identical twins - split egg

Fraternal twins - 2 eggs, 2 sperm

just googled it, yeah its correct, well ill be damned

 

[wildchild]

why did you call me a she? and yes its correct

 

[Road Demon]

No only one sperm per egg, here are the events associated with the block to polyspermy ( ie more than one sperm fertilizing an egg).

Binding of sperm to the zona pellucida is the easy part of fertilization. The sperm then faces the daunting task of penetrating the zona pellucida to get to the oocyte. Evolution's response to this challenge is the acrosome - a huge modified lysosome that is packed with zona-digesting enzymes and located around the anterior part of the sperm's head - just where it is needed.

The acrosome reaction provides the sperm with an enzymatic drill to get throught the zona pellucida.

Upon binding of a sperm, the egg rapidly undergoes a number of metabolic and physical changes that collectively are called egg activation. Prominent effects include a rise in the intracellular concentration of calcium, completion of the second meiotic division and the so-called cortical reaction.

The cortical reaction refers to a massive exocytosis of cortical granules seen shortly after sperm-oocyte fusion.

Cortical granules contain a mixture of enzymes, including several proteases, which diffuse into the zona pellucida following exocytosis from the egg. These proteases alter the structure of the zona pellucida, inducing what is known as the zona reaction. Components of cortical granules may also interact with the oocyte plasma membrane.

The zona reaction refers to an alteration in the structure of the zona pellucida catalyzed by proteases from cortical granules. The critical importance of the zona reaction is that it represents the major block to polyspermy in most mammals.

This effect is the result of two measurable changes induced in the zona pellucida:


The zona pellucida hardens. Crudely put, this is analogous to the setting of concrete. Runner-up sperm that have not finished traversing the zona pellucida by the time the hardening occurs are stopped in their tracks.


Sperm receptors in the zona pellucida are destroyed. Therefore, any sperm that have not yet bound to the zona pellucida will no longer be able to bind, let alone fertilize the egg.

 

[wildchild]

wouldnt there be a freak chance that more than one sperm could attack an egg at the same time? Also I have one more question about sperm - i heard that you get sperm to fertilize eggs but also other types of sperm that just fight off other mens sperm ( these spearm are oddly shaped and not ment to fertilize and egg) what would happen if one of these sperm by accident fertilized an egg?

thanks for all the answers people

 

[Road Demon]

Possible mechanisms of sperm competition, i.e. the kamikaze sperm hypothesis. This hypothesis states that sperm from different males interact to incapacitate each other in a variety of ways.


In many species, females mate with males in such quick succession that sperm from various depositors find themselves vying for the same prize. As a result, chimps, for example, have evolved larger testicles to churn out more sperm; some insects scrape out enemy sperm before depositing their own; and fruit flies poison competitors' spermatozoa.

Based on an increased clumping together--which makes sperm less mobile--and a higher mortality rate in mixed sperm samples, reproductive biologist Robin Baker, formerly of the University of Manchester, proposed a decade ago that some mammals, including humans, manufacture "killer" sperm whose only function is to attack foreign spermatozoa, destroying themselves in the process.

According to the so-called kamikaze sperm hypothesis, sperm from different
males sabotage each other in the run for the same egg. ...

Not sure if this happens in humans, mixed evidence for the support of the kamikaze sperm hypothesis...

 

[wildchild]

i found out if alot of sperm attack an egg and try to get in at the same time it can kill the egg because of chemicals realised by the sperm. Does anyone know the answer to the question about if a sperm not ment for inseminating the egg accidently gets into the egg?