Video Transcript
Regarding the genetic material of
prokaryotes and eukaryotes, which of these statements is true? (A) Both eukaryotic DNA and
prokaryotic DNA are circular. (B) Plasmids are found mostly in
eukaryotes. (C) Prokaryotes cannot survive
without plasmids. (D) None of the statements are
correct.
This question is asking us to
compare the DNA in prokaryotes and eukaryotes, which are two of the major domains of
life. Here’s a diagram that illustrates a
prokaryotic and eukaryotic cell. Let’s go through some of the
differences that we find in their DNA.
Probably the best known difference
is that a eukaryotic cell contains a nucleus to house its chromosomal DNA, while the
prokaryotic cell does not. In the prokaryote, there’s actually
a nuclear region where the DNA is concentrated that’s called the nucleoid.
Another difference is that
prokaryotes usually have a single circular chromosome compared to eukaryotes, which
generally have multiple linear chromosomes. Because prokaryotes generally have
a single chromosome, they are often haploid, while eukaryotes typically contain two
or more copies of their chromosomes. So they’re generally diploid or
higher.
In terms of compacting DNA,
prokaryotes generally don’t use histones to compact their DNA, whereas eukaryotes
do. Prokaryotes tend to have additional
DNA apart from the chromosomal DNA that are called plasmids. These plasmids can contain extra
genes that can help prokaryotes adapt to their environment. Eukaryotes generally don’t have
plasmids, although there are some exceptions.
Now that we’ve gone through some of
the differences between prokaryotic and eukaryotic DNA, let’s look at our answer
choices to see which one is true.
Answer choice (A) is false since
eukaryotic DNA is generally linear and not circular like prokaryotic DNA. Answer choice (B) is also incorrect
since plasmids are mostly found in prokaryotes and not in eukaryotes. Answer choice (C) is also
incorrect. Plasmids help prokaryotes adapt to
their environment with additional genes. And in some cases, these genes are
necessary for survival. But generally, the chromosomal DNA
is what is required for the prokaryote to survive.
Therefore, the correct option is
given by answer choice (D). None of these statements are
correct.
