Video Transcript
Which of the following statements
is correct about the sex chromosomes contained in the sperm and ova? (A) Ova only carry X chromosomes,
whereas sperm can carry either X or Y chromosomes. (B) Ova only carry Y chromosomes,
whereas sperm can carry either X or Y chromosomes. (C) Sperm only carry X chromosomes,
whereas ova can carry either X or Y chromosomes. (D) Sperm only carry Y chromosomes,
whereas ova only carry X chromosomes.
This question asks us about the sex
chromosomes contained in the sperm and ova. Sperm and ova are gametes and are
haploid, meaning they contain half the number of chromosomes compared to body
cells. In humans, we have 46 chromosomes
in total in our body cells but 23 in our gametes. During fertilization, the ova and
sperm cell combine their chromosomes to give 46 chromosomes in the zygote. Each gamete contains 23
chromosomes. Chromosomes one to 22 are called
autosomes, and chromosome 23 is called the sex chromosome because it determines our
biological sex.
The sex chromosome can be either X
or Y. If two X chromosomes are inherited,
then a biological female results, and if an X and Y chromosome are inherited, then
the result is a biological male. Since gametes contain half the
chromosomes, this female can then go on to produce gametes that contain either the
first X chromosome or the second X chromosome, while the male will produce sperm
that contains either the X chromosome or the Y chromosome.
Therefore, the correct answer is
(A). Ova only carry X chromosomes,
whereas sperm can carry either X or Y chromosomes.
