Zygote

Definition

A zygote is a single cell formed when two gametes, usually a sperm and an egg, fuse during fertilization. This initial cell is the first stage in the development of a new organism and marks the beginning of embryogenesis, leading to seed development in plants. The zygote contains a complete set of genetic material from both parents, setting the stage for growth and differentiation into various tissues and structures.

5 Must Know Facts For Your Next Test

1. The zygote undergoes rapid mitotic divisions known as cleavage shortly after fertilization, leading to the formation of an embryo.
2. In plants, the zygote typically develops within the ovule, eventually forming a seed that contains the potential for a new plant.
3. The zygote's genetic makeup is a mix from both parents, ensuring genetic diversity in the resulting offspring.
4. In angiosperms, double fertilization occurs, resulting in a zygote and a triploid endosperm that provides nourishment to the developing embryo.
5. Zygote formation is crucial for sexual reproduction, allowing for variation and adaptation in plant populations.

Review Questions

• How does the formation of a zygote initiate the process of embryogenesis in plants?
  • The formation of a zygote initiates embryogenesis by establishing the foundation for development. After fertilization, the zygote begins dividing through mitosis, leading to an increase in cell number and forming an embryo. As these cells continue to divide and differentiate, they will develop into various tissues and structures essential for the growing plant.
• Discuss the role of genetic diversity introduced by zygotes in plant populations.
  • Zygotes play a vital role in introducing genetic diversity within plant populations by combining genetic material from two distinct parents. This mixing of genes results in offspring with unique traits that can better adapt to changing environments or resist diseases. Genetic diversity is essential for the survival and evolution of species, ensuring resilience against environmental pressures.
• Evaluate the significance of double fertilization in angiosperms concerning zygote formation and seed development.
  • Double fertilization is significant in angiosperms as it leads to both zygote formation and the development of a triploid endosperm. The zygote develops into an embryo while the endosperm provides essential nutrients during seed development. This dual process enhances reproductive success by ensuring that the developing embryo has adequate resources for growth, ultimately increasing seed viability and enhancing survival rates in varying environments.

Related terms

Fertilization:

The process by which male and female gametes unite to form a zygote, initiating the development of a new organism.

Embryo: The early stage of development following the zygote, where cell division and differentiation begin to form distinct tissues and organs.

Seed:

A mature ovule containing the zygote's genetic material, surrounded by protective layers, which can develop into a new plant under suitable conditions.