Dictionary » O » Ovum



noun, plural: ova

(1) Female gamete; female sex cell; female reproductive cell.

(2) Egg cell.


In humans, the ovum is the largest cell visible to the naked eye. It is about 0.1 mm in size in humans. It is produced in the ovary and eventually released into the fallopian tube during ovulation. It consists of protoplasm (with some yolk) surrounded by a think cell wall (vitelline membrane). It may also have a noncellular covering (zona pellucida). Within the cell is a large nucleus (germinal vesicle), with a nucleolus (germinal spot). The cell is haploid so that when a sperm cell fertilizes it, it forms a diploid zygote.


Compare: sperm cell

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Human Gamete Compatibility Going Backwards

... more detail and less generic. If you could take human sperm back, say, 500 years and "test" it for compatibility with every female ovum you would find general compatibility. In other words, if a modern male and a female from the 1,500's had sex, a normal offspring would be likely. ...

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by BiologicalRush
Tue Jun 24, 2014 9:01 pm
Forum: Evolution
Topic: Human Gamete Compatibility Going Backwards
Replies: 9
Views: 8775

Why must we avert the genome of Eden?

... bacteria, but primeval stem cells in which the course of evolution was encoded, just like the process of ontogenesis is determined in a fertilized ovum. To back up this radical conclusion, let's see some of the evidence which I've found compelling. 1. Ernst Walter Mayr's prediction In 1963 Ernst ...

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by Hunor
Mon Sep 23, 2013 12:08 am
Forum: Evolution
Topic: Why must we avert the genome of Eden?
Replies: 6
Views: 14528

Human Reproduction

I read a line in my text stating "after 14 days of ovulation , if ovum is not fertilized , the lining of uterus degenerates and menstruation begins." Why does the endometrium degenerates ? Please Help!! :?

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by madromanoff
Thu Jan 17, 2013 4:26 pm
Forum: Human Biology
Topic: Human Reproduction
Replies: 1
Views: 1791

Sperm and White blood cells

Hi Guys, I have been trying to research about the type of Leukocyte present in 'attacking' the sperm cells during its journey towards the ovum. So far I have had no luck. Now, I would really appreciate it if someone could further explain this process in more detail or give me a resource that ...

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by dzel
Fri Oct 12, 2012 9:40 pm
Forum: Cell Biology
Topic: Sperm and White blood cells
Replies: 0
Views: 1740

How does seeds formed after pollination?

I guess fertilization can occur many times within one plant. Some flowers might have several ovules. Each ovule contains one ovum. When pollen grains land on the stigma, more than one pollen tubes can be formed and each carries a male gamete to one ovule.

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by AndyYip
Sat Sep 29, 2012 4:20 pm
Forum: Botany Discussion
Topic: How does seeds formed after pollination?
Replies: 1
Views: 5607
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