Video Transcript
What is a zygote? (A) A fertilized egg cell. (B) A fertilized sperm cell. (C) A developed embryo. (D) An adult sperm cell. Or (E) an undeveloped egg cell.
A zygote is the earliest
developmental stage of a multicellular organism. It is a part of sexual
reproduction. During sexual reproduction, two
haploid gametes, typically a sperm cell and an egg cell, fuse to form one diploid
cell. The gametes are said to be haploid
because they only have half the typical number of chromosomes or half the genetic
information of an organism.
The two gametes fuse so that the
offspring inherits genetic information from both parents. For example, human cells possess 23
pairs of chromosomes or 46 in total. When humans reproduce, the
offspring inherits 23 chromosomes from one parent and 23 from the other, adding up
to a total of 46. When gametes fuse together, the
process is called fertilization.
In humans, the female parent
produces an egg cell, and the male parent produces the sperm cell. The egg is many times larger than
the sperm and contains the organelles and cellular mechanisms needed for growth and
development. The sperm has the more simple job
of delivering the genetic information from the male parent to the egg.
The nucleus of the sperm is
absorbed by the egg, and the egg is said to be fertilized. The fertilized diploid cell is
called the zygote. The zygote will begin to divide and
eventually develop into an embryo and then a fetus and finally a baby human. Now, we’re ready to choose the
correct answer. What is a zygote? A zygote is a fertilized egg
cell.
