Video Transcript
The diagram shows a basic outline
of the process of fertilization. How many chromosomes will be in the
nucleus of the sperm cell? (A) 46 chromosomes, (B) 12
chromosomes, (C) 23 chromosomes, (D) 48 chromosomes, (E) two chromosomes.
This question is asking us to
identify how many chromosomes will be in the nucleus of a sperm cell. In order to answer this question
correctly, we will review the process of fertilization, focusing on how the number
of chromosomes from a gamete or sex cell are determined.
Most cells in the human body are
called somatic cells, and they make up most every organ and tissue. Somatic cells are diploid. The prefix diplo- in the word
“diploid” comes from Greek and means double. This refers to the two copies of
each chromosome in somatic cells. This means in diploid cells there
are 46 chromosomes.
In contrast to somatic cells, sex
cells, which are also known as gametes, are only found in the gonads. Gametes are haploid cells. The prefix haplo- in the word
“haploid” comes from the Greek word for single and refers to the single copy of each
chromosome found in haploid cells. This means in haploid cells there
are half as many chromosomes found in diploid cells. So there are only 23 chromosomes
within haploid cells.
In human females, the gametes are
called ova or egg cells, while in human males, the gametes are called sperm
cells. In human fertilization, the sperm
and the egg fuse together to form a zygote. Since both the sperm and egg cells
are haploid cells, they each contain 23 chromosomes. This means when they fuse together
to form a zygote, the zygote will contain 46 chromosomes, which is the number of
chromosomes found in somatic cells. So, in order to create a zygote
with 46 chromosomes, the sperm must contain 23 chromosomes.
Now that we’ve discussed how many
chromosomes each gamete should contain, we’re able to answer our question
correctly. So the number of chromosomes that
will be in the nucleus of a sperm cell is 23 chromosomes.
