Video Transcript
True or False: The genome of a
eukaryotic organism is the same in a cardiac cell and a liver cell within one
individual.
To answer this question, let’s
first review the key term “genome.”
The genome is all the genetic
material of an organism; it’s complete DNA. You likely already know that
prokaryotes, such as the bacterium drawn here, are single celled. This means that all the DNA in a
prokaryotic genome comes from just one cell. For example, bacterial DNA can be
found in two locations within the cell: on a single closed chromosome and on small
circular structures called plasmids. So, a bacterium’s genome would
include all the nucleotide sequences from both of these locations.
Eukaryotic organisms can be single
or multicellular and include fungi, plants, and animals. Like a prokaryotic genome, the
genome of a single-celled eukaryote, such as the yeast cell drawn here, contains all
the DNA found in that cell. But what about the genome of a
multicellular eukaryote? Does each cell have a unique
genome? Or does the genome just differ
between types of cells, like the cardiac and liver cells in our question? Well, all the cells within a given
eukaryotic organism contain the same DNA. As a result, the genome of a
multicellular eukaryote contains all the DNA found in any one of its cells.
Numerous types of cells can arise
from the same genome because cells undergo different levels of transcription and
translation of each gene. This is called the level of gene
expression. The level of gene expression in
each undifferentiated cell determines whether it will develop into a sperm cell, a
neuron, a red blood cell, or any of the other cell types in the organism.
We now have enough information to
answer our question. The statement “The genome of a
eukaryotic organism is the same in a cardiac cell and a liver cell within one
individual” is true.
