Difference Between Sperm and Ovum

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The two important cells of the human reproductive system are sperm and ovum, the former being male reproductive cell and the latter being a female reproductive cell. Both of these cells are responsible to undergo fertilization through fusion and formation of zygote. However, you will learn about the difference between ovum and sperm related to certain characteristics, structure and functionalities in this article. 


What is Sperm?

It is the male gamete or reproductive cell that plays a major role in the reproduction process in humans and other animals. A motile sperm with a tail also called flagellum is produced by animals and it is known with the name spermatozoa whereas algae and fungi are known to produce non-motile sperm cells called spermatia. Talking about the plants, the flowering group contains non-motile sperm inside the pollen and some plants such as fern and gymnosperms consist of motile sperm.

Human sperm cell is haploid and consists of 23 chromosomes which join with the 23 chromosomes of the female egg or ovum to form a diploid cell. Sperm is stored in the epididymis  and during ejaculation, it is released from the penis along with a fluid called semen.


Sperm Structure

Talking about the anatomy of a sperm cell, it can be divided into head and tail. The head contains nucleus with densely coiled chromatin fibers and is anteriorly surrounded by a thin and flattened sac known as acrosome. Acrosome contains enzymes that help in the penetration into the female egg or ovum. The head portion of a sperm also contains vacuoles. On the other hand, the tail which is also known as flagellum is the longest part of a sperm and goes into a wave-like motion that helps the sperm to swim and penetrate the egg. The four parts of the tail include the connecting piece, principal piece, midpiece and the end piece. 

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What is Ovum?

Also called the egg cell or ova in plural, it is the female gamete or reproductive cell present in humans and most of the animals. Ovum is non-motile and when the egg or ovum fuse with sperm during fertilization, a zygote or a diploid cell is formed that can grow further into a new organism. Sometimes, the young ovum of an animal is termed as ovule. Mammals have numerous ova at birth and these mature through oogenesis. In all the mammals including humans, the ovum is fertilized inside the female body. It is one of the largest cells in the human body and is visible even to the naked eye without the help of a microscope. It measures approximately 0.1 mm in diameter in humans. Ovum is called oosphere in algae.


Ovum Structure

Ovum has a cell substance at its center called the yolk or ooplasm. Ooplasm contains a nucleus named the germinal vesicle and also nucleolus called the germinal spot. Ooplasm has formative yolk and nutritive yolk, the formative yolk is the cytoplasm of an ordinary animal cell and the nutritive yolk (deutoplasm) is made of rounded granules composed of fatty and albuminoidal substances in the cytoplasm. The latter helps in nourishing the embryo in the early stages of developmental phase in mammals. On the other hand, birds contain egg nutritive yolk which is enough to supply its chick enough nutrients throughout the period of incubation.

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We will highlight the differences between sperm and ovum in a tabular chart as follows.

Difference Between Ovum and Sperm

Differences

Sperm

Ovum

Definition

It is the male gamete or male reproductive cell.

It is a female gamete or female reproductive cell.

Motility 

It is a motile cell having flagella that helps in its movement and penetration into ovum.

It is non-motile and doesn’t possess any flagella.

Size of cell

It is the smallest cell in the human body.

It is one of the largest cells in the human body.

Location of mitochondria

Mitochondria is centrally located in this cell.

Mitochondria is scattered in the cytoplasm of the cell.

Amount of Cytoplasm

Cytoplasm is present in very small amounts in sperm cells.

Cytoplasm is present in large amounts in the egg cell or the ovum.

Nucleoplasm present/absent

Nucleoplasm is absent in the cell.

Nucleoplasm or the germinal vesicle is present in the egg cell.

Type of Chromosomes

Sperm cells contain X or Y chromosomes. 

Egg cells contain only X chromosomes.

Centrioles present/absent

Centrioles are present in the sperm cell.

Centrioles are absent in the sperm cell.

Where are they produced?

Sperms are produced in the testes, male reproductive organ.

Ovum is produced in the ovary which is a female reproductive organ.

Segmentation

A sperm is segmented into head, neck and tail.

Ovum has no such segmentation or similar structure.

Formation

One spermatogonium results in the formation of four sperms.

One oogonium results in the production of only one ovum.

Surrounding

A sperm cell is surrounded by a plasma membrane.

An ovum cell is surrounded by egg envelopes.

FAQ (Frequently Asked Questions)

1. What is the Difference Between Sperm and Egg Cells?

Sperm are male reproductive cells or male gametes produced in the male reproductive organs known as the testes whereas egg cells are ovum (ova), female gametes produced in the female reproductive organs called ovaries. Both of them differ in their structure, however, these come together to fuse and form a zygote that results into a new organism.

2. What is Fertilisation?

It is the fusion of two gametes, one from male and another from female in humans that lead to the development of a new individual offspring or organism. In humans, sexual reproduction is the process where the cycle of fertilization and development of new offspring takes place. Other terms used for fertilization in different organisms include insemination, pollination, syngamy, impregnation and generative fertilization. 

3. What is a Diploid Cell?

A diploid cell is formed when the nucleus of both the sperm (haploid) and an egg (haploid) fuse. A diploid cell is also called zygote.

4. What is Artificial Insemination?

It is the artificially done fertilization process where introduction of sperm into female’s uterine cavity or female’s cervix is performed deliberately to achieve pregnancy. It is also in vivo fertilisation which is an alternative to achieve a new offspring other than sexual intercourse.