Video Transcript

Chromosomes are formed from the
nucleic acid DNA. What is the primary function of
these chromosomes? To keep the contents of the nucleus
and the cytoplasm separate. To act as the site of cellular
respiration. To provide essential nutrition for
the cell. Or to carry genetic information and
allow it to be passed from parent to offspring.

Let’s start by deciphering the
information in the question and what we already know about the structure and
function of chromosomes. Each chromosome is a large unit
used by cells to organize and store their DNA. You can see a chromosome on the
diagram here. Chromosomes can be made up of one
or two chromatids. In this case, it consists of two
chromatids. If this chromosome was to unravel
and if we had a very sophisticated microscope so we could zoom in really close on
it, we might be able to see the DNA like it’s shown in the side of the diagram
here.

DNA is the molecule that carries
the genetic instructions for life. It can be passed on from a parent
to their offspring. DNA takes the shape of a double
helix. DNA is found in the form of these
chromosomes in the nucleus of almost all eukaryotic cells. This nucleus is surrounded by a
membrane called the nuclear envelope, which controls what can enter and leave the
nucleus. As the nuclear envelope is a
membrane, it also acts to separate the nucleus and its contents from that of the
cytoplasm. Now that we know a little bit more
about chromosomes and their function, let’s try to work out the correct option using
the process of elimination.

When a question asks for the
primary function of something, several of the answers may seemingly be correct. We are looking for the option which
defines the function of chromosomes best. So all answers must be carefully
scrutinized. One of our options refers to
keeping the contents of the nucleus and the cytoplasm separate. This is a role of a membrane, and
in this specific case, it is referring to the nuclear envelope. Chromosomes, however, are not
membranes, and therefore this option can be eliminated.

Another of our options refers to
the site of cellular respiration. Cellular respiration does not occur
in the nucleus of eukaryotic cells but in a different organelle called a
mitochondrion, which is pictured here. This is, therefore, not a function
of a chromosome. The next option refers to another
key life process other than respiration, which is obtaining nutrition. Some eukaryotic organisms can
obtain nutrition from structures within their own cells, such as plants, which have
chloroplasts in their cells, like the one pictured here.

Plants carry out a process called
photosynthesis, using light energy to synthesize glucose in these chloroplasts. Not all eukaryotes have
chloroplasts, so not all of them can obtain nutrition within their own cells,
however. This cannot therefore be a role of
a structure common to all eukaryotic organisms, such as the chromosome, so this
option is also incorrect.

This leaves us with the option that
defines the two main aspects required when defining the function of chromosomes that
they hold genetic information in the form of DNA and that this genetic information
is heritable. So it could be passed from a parent
onto their offspring. So, the primary function of
chromosomes is to carry genetic information and allow it to be passed from a parent
to offspring.

You are watching: Question Video: Defining the Function of Chromosomes. Info created by GBee English Center selection and synthesis along with other related topics.