Video Transcript
Chromosomes are arranged in homologous pairs in the nucleus of eukaryotic cells. What is meant by the term homologous pairs? Pairs of chromosomes that are of a similar length and that have a similar gene
positioning. Pairs of chromosomes that contain the same alleles. Pairs of chromosomes that code for the same characteristics in different
organisms. Or pairs of chromosomes that are inherited from one parent.
This question is asking us to recall the relationship between chromosomes and
homologous pairs. To answer this question, we’ll review key facts about genetic material. DNA is the genetic material found in all living organisms. DNA is found in the nucleus of human cells. Since DNA carries all of the genetic instructions for life, it is a very long
molecule. And depending on the complexity of the organism, more than one DNA molecule may be
needed to carry all of the information.
To fit all of the long DNA molecules into the smaller-sized nucleus, DNA is packaged
into structures called chromosomes. One chromosome is one DNA molecule. Each species is characterized by a specific number of chromosomes. Chromosomes are usually found in pairs, so the 46 individual chromosomes in humans
are organized into 23 pairs. The 23 pairs of chromosomes are inherited from our biological parents. We get one set of chromosomes from our biological mothers and another set of
chromosomes from our biological fathers.
Despite the difference in their origin, the chromosomes in each pair share several
structural similarities. The chromosomes in the pair are the same size, same shape, and have the same
centromere positioning. Most importantly, they have the same genes in the same locations. Since these chromosomes have the same size, same shape, and the same genes in the
same locations, they are called homologous. The word homologous means same structure. The prefix homo- is often used in biology and comes from the Greek word for same or
similar.
Using the knowledge we now have, let’s look at our answer options and select the
correct one. The term homologous pairs means pairs of chromosomes that are of a similar length and
that have a similar gene positioning.
