Fertilization begins the development of a new organism by bringing together the genetic material of an egg and a sperm. This lesson explains how the gametes unite and how the egg prevents more than one sperm from entering.
Fertilization is the process in which an egg and a sperm fuse to form a zygote. Each gamete contains one set of chromosomes, making each haploid. When their genetic material combines, it forms the zygote’s diploid genome, with a complete set of chromosomes.
All flashcards
What is a zygote?
The cell formed when the genetic material of an egg and sperm unite; it is the first cell of a developing organism.
What is the zona pellucida?
A glycoprotein-rich extracellular matrix surrounding a mammalian egg.
What do acrosomal reactions help sperm do?
Pass through the egg’s protective matrix and reach the egg membrane.
What is polyspermy?
The entry of more than one sperm into an egg, usually producing an abnormal chromosome complement.
What is the inner cell mass in a mammalian blastocyst?
The cell population that forms the embryo.
Quiz questions
During cleavage, what happens to the embryo’s overall mass as its cell number increases?Answer: Its overall mass remains approximately unchanged.
What structure characterizes a typical blastula?Answer: A cell layer surrounding a fluid- or yolk-filled cavity.
How does holoblastic cleavage differ from meroblastic cleavage?Answer: Holoblastic cleavage passes through the whole egg; meroblastic cleavage is partial.
Which statement correctly describes the trophoblast in a mammalian blastocyst?Answer: It is the outer cell layer and contributes to the placenta.
What is the central developmental result of gastrulation?Answer: Cell rearrangement establishes the germ layers and foundations of the body plan.
Based on Biology 2e by Mary Ann Clark, Matthew Douglas, Jung Choi (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.