Video Transcript
Which of the following correctly
compares the size of sperm and egg cells in humans? (A) The sperm cells are much larger
than the egg cells. (B) The egg cells are much larger
than the sperm cells. (C) The sperm and egg cells are
equal in size.
To answer this question, we must
recall what we know about the size of the sperm cell and egg cell in humans. Let’s start by reviewing what we
know about the egg cell. A mature egg cell is a spherical
cell measuring about 0.1 to 0.2 millimeters in diameter, which is roughly the same
size as a single grain of table salt. This means the egg cell is one of
the largest human cells. The large size of the egg cell is
because several structures of the egg cell are used to store nutrients that support
the maturation of the egg cell and its development after fertilization.
Now let’s review what we know about
the sperm cell. When measured from tip to tail, the
sperm cell is approximately 55 micrometers long, which is roughly the same size as a
pollen grain. This means, in contrast to the egg
cell, the sperm cell is one of the smallest cells of the human body. The small size of the sperm cell is
because its major function is to swim to the egg cell. So, the sperm cell has much less
cytoplasm than the egg cell, reducing its size and streamlining it for swimming.
So, if you were to compare the
diameter of the egg cell to the length of the sperm cell, the sperm cell is about
three to four times smaller than the egg cell. However, the difference in volume
between the egg cell and the sperm cell is much more drastic. The volume of the egg cell is about
10 million times that of the sperm cell, which is due to their differences in
cytoplasm. From this review, we now recall
that the sperm cell is much smaller than the egg cell.
With this information, we are now
ready to answer the question. Therefore, the egg cells are much
larger than the sperm cells.
