Gametes and zygotes are key players in the reproductive system. While the two bear strong associations, they are far from being interchangeable.
Summary Table
| Gamete | Zygote |
| Developed by the process of meiosis | Formed by the fusion of two gametes |
| A haploid cell that contains 23 chromosomes | A diploid cell that contains 46 chromosomes |
| Carries only 1 sex chromosome (Y or X) and 1 copy of autosomes | Carries 2 sex chromosomes (XY or XX) and 2 copies of autosomes |
| Develops either in the testes (for males) or ovaries (for females) | Develops in the fallopian tube |
| A male gamete is motile while a female gamete is non-motile | Non-motile |
| A male gamete has a tadpole-like structure while a female gamete is large and spherical | Large and spherical |
Definitions
Getty Images/Science Photo Library/ANDRZEJ WOJCICKI
A gamete is a reproductive cell that plays a critical role in the process of fertilization. Produced by organisms that sexually reproduce, a male gamete (also called a sperm cell) fuses with a female gamete (also called ovum or egg cell) to develop a zygote.
Getty Images/Science Photo Library/ANDRZEJ WOJCICKI
A zygote, on the other hand, is a eukaryotic cell formed by the unity of a male and a female gamete. A product of fertilization, a zygote matures into a fetus during the late stages of reproduction.
Gamete vs Zygote
Even though both are important in the process of fertilization, there is a big difference between a gamete and a zygote.
Development
A male gamete and a female gamete are developed by the process of meiosis – a type of cellular division where a parent cell splits into four daughter cells. Each daughter cell carries half the number of chromosomes of the parent cell. A zygote, by comparison, is the product of the fusion of two gametes. A male gamete (sperm cell) travels towards the female gamete (egg cell) during fertilization. A fertilized egg is known as a zygote, which later develops into an embryo and then into a fetus.
Genetic Composition
A gamete is a haploid cell that contains 23 chromosomes, which is half of the chromosomes necessary to develop a new organism. Because of its composition, it is only able to carry half of the genetic materials necessary to create and sustain life. A zygote, by contrast, is a diploid cell that has 46 chromosomes. It is the carrier of the complete set of genetic materials necessary for fetal development.
Chromosome Composition
Chromosomes are thread-like, circular structures made up of hereditary units called genes. There are two major types of chromosomes: autosomes and sex chromosomes. As the name implies, sex chromosomes are integral for identifying sex. Females carry identical sex chromosomes (XX), while males have two different chromosomes (XY). Autosomes, on the contrary, have no sex-determining ability. A gamete has only 1 sex chromosome (Y or X) and 1 copy of autosomes. After two gametes successfully unite, the chromosomes of each gamete combine, which explains why a zygote carries 2 sex chromosomes (XY or XX) and 2 copies of autosomes.
Site
Gametes exist in two types: a male gamete and a female gamete. While the male gamete is located in the testis, the female gamete is developed in the ovary. A zygote, on the other hand, is only found in the female reproductive system. To be specific, a zygote is initially developed in the fallopian tube.
Motility
There are major differences between a gamete and a zygote in terms of mobility. A male gamete (or a sperm cell) is motile in nature, and it can travel and reach the fallopian tube within 45 minutes. However, only a few can survive the hostile environment in the woman’s reproductive system. Unlike a male gamete, a female gamete (egg cell) and a zygote are both non-motile.
Shape
A female gamete and a zygote bear close resemblance as they are both large and spherical, while a male gamete is a tadpole-like structure that has the ability to swim towards the fallopian tube.