Video Transcript
Fill in the blanks. When a male and a female gamete
fuse together during fertilization, they form a single cell called blank. This blank then undergoes growth
and development through mitotic divisions. (A) An embryo, embryo; (B) a fetus,
fetus; (C) a blastocyst, blastocyst; or (D) a zygote, zygote.
This question asks us to select the
correct terms that complete the sentence about the cell produced following
fertilization. Fertilization occurs when the male
gamete, a sperm cell, fuses with the female gamete, an egg cell. When the sperm cell and egg cell
fuse, they produce a single cell that contains all the genetic information needed to
develop into a baby. But what cell forms following the
process of fertilization? This question asks us to correctly
name the cell produced when the sperm and egg cell have joined.
Let’s have a look at our answer
options to work out which would fill in the blanks correctly. Option (A) refers to an embryo. An embryo is the early
developmental stage of an organism, formed when a zygote undergoes several cellular
divisions. This answer cannot be correct, as
we are looking for a term which refers to a single cell, and an embryo is formed
following several divisions. We can therefore eliminate answer
choice (A).
Answer choice (B) gives us the term
fetus. A fetus develops about eight weeks
after fertilization and contains almost all the major organ systems. This cannot be our correct answer,
as we are looking for a term to describe a single cell. A human fetus, for example, is
recognizable as developing into a baby and contains many cells. We can also eliminate answer choice
(B).
Answer choice (C) refers to a
blastocyst. A blastocyst is formed during the
early stages of the development of the embryo, around five to seven days after
fertilization. As the diagram shows, the
blastocyst is made up of more than one cell and, in fact, contains different cell
types. So, this cannot be our correct
answer, as we are looking for a term describing a single cell. We can therefore eliminate answer
choice (C).
We are left with our correct
answer. A zygote is formed by the fusion of
male and female gametes in sexual reproduction. The zygote grows and develops to
become a new offspring. A zygote is a single cell. It is formed once the male and
female gametes fuse during fertilization. So, the correct answer is given in
answer choice (D). When a male and a female gamete
fuse together during fertilization, they form a single cell called a zygote. This zygote then undergoes growth
and development through mitotic divisions.
